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See also: assay, reaction, reagent, scale, stain.
See also: assay, reaction, reagent, scale, stain.
testAssay Medtalk The quantitative or qualitative measurement of a substance or process. See Acid loading test, Acid hemolysis test, Acid perfusion test, Agar-diffusion test, Agglutination test, AIDS test, Anterior drawer test, Antimicrobial sensitivity test, Anti-DNase B test, Antiglobulin test, Anti-glomerular basement membrane test, Apprehension test, Arginine test, Arterial blood gas test, Ascorbate-cyanide test, Aspergillosis precipitin test, Aspergillus antigen skin test, Autohemolysis test, Back bleeding test, Bar-reading test, Barium burger test, BarOn test, Baseline test, Bedside test, Bentiromide test, Benton VFT test, Bethanechol sensivity test, Bile solubility test, Billable test, Biomedical test, Bleeding time test, Block sorting test, Breath test, But for test, C-peptide suppression test, Calcitonin suppression test, Caloric test, Cancer screening test, Capillary fragility test, Carbon dioxide challenge test, Carrier test, Chi squared test, Chromogenic (enzyme) substrate test, Cis-trans test, Citric acid urine test, Clinical laboratory test, Clomiphene stimulation test, Clonidine suppression test, Cochran-Mantel-Haenzel test, Colorimetric test, Combined anterior pituitary test, Commodity test, Complement fixation test, Complex test, Contraction stress test, Coombs' test, Copper sulfate test, Cover test, CRH stimulation test, Definitive test, Denver developmental screening test, Deoxyuridine suppression test, Developmental screening test, Dexamethasone suppression test, Diagnostic test, Differential renal function test, D-dimer screening test, Direct antiglobulin test, Doerfler-Stewart test, Donsbach's nutrient deficiency test, Durham test, Draw-a-person test, d-xylose absorption test, EDAC test, ELM test, Esoteric test, Exercise test, F test, F-max test, Fagan test, Farr test, Fecal occult blood test, Feminist test, Filippi test, Finger-to-nose test, Fisher's exact test, 40 millimeter test, Free PSA test, Full-Range Picture-Vocabulary test, Function-way-result test, Functional test, Functional gene test, Functional intact fibrinogen test, Fungal test, Germ tube test, Glucose tolerance test, GnRH stimulation test, Goldstein-Scheerer test, Goodenough-Harris Drawing test, Ham test, Heel-to-knee-to-shin test, HER-2/neu test, Highly complex test, HIV test, Hollander test, Home test, Hormone receptor test, House-tree-person test, HRV test, Hybrid Capture® CMV DNA test, Hyperemia test, Illinois Test of Psycholinguistic Abilities, Indican test, Indirect antiglobulin (Coombs) test, Indole spot test, Irresistible impulse test, Kahn Test of Symbol Arrangement, Kappa-lambda test, Kiss of death test, Kleihauer-Betke test, Kveim test, Lab test, Labyrinthine test, Lachman test, 2H-lactose test, Lactose intolerance test, Latex agglutination test, Laxity test, Leishmanin skin test, Leprominin skin test, Leukocyte bactericidal test, Level 1 test, Level 2 test, Liebermann-Burchard test, Limulus amebocyte lysate test, Liver function test, Load & shift test, Lombard (voice-reflex) test, Lupus band test, Lysine decarboxylase test, Malonate test, Management test, Mann-Whitney U test, Mantoux (tuberculin skin) test, Marshmallow test, Match test, Mercaptoethanol agglutination inhibition test, Methyl red test, Milk ring test, Mills' test, Mini-mental test, Mirror test, M'Naughten test, Moderately complex test, Monospot test, Morton's test, Motility test, Mouse footpad test, Mucin clot test, Multiple puncture test, Multiple sleep latency test, Mumps skin test, Myoglobin cardiac diagnostic test, Nafarelin test, Naffziger's test, NAP test, Navarro urine test, NBT test, Neostigmine test, Neuraminidase inhibition test, Neutralization test, Neutrophil hypersegmentation test, Niacin test, Ninhydrin test, Nitrate reduction test, Nonparametric test, Nonstress test, Occult bood test, O-F test, One-tail test, Optochin (disk) test, Ordered test test, Orientation test, Ornithine decarboxylase test, Osmotic fragility test, Oxidase test, Oxygen test, Oxytocin stress test, Pancreolauryl test, Panel test, Parametric test of significance test, Parathyroid squeeze test, Patrick's test, Paul-Bunnell-Davidsohn test, Penile stress test, Pentagastrin test, Performance test, Personality test, Perthes' test, Phenolphthalein test, Phenolsulfonphthalein test, Phentolamine test, Physician test, Pituitary function test, Plantar ischemia test, Platelet adhesion test, Postage stamp test, PPD test, Prausnitz-Küstner test, Predictive gene test, Pregnancy test, Prenatal test, Prick test, PRIST test, Projective test, Potein-bound iodine test, PROVERBS test, Provocative test, Psychologic test, Psychomotor test, Pulmonary function test, Pulp vitality test, Q-tip test, Quellung test, QuickScreen™ at-home drug test, Rabbit ileal loop test, Radiosensitivity test, Radioimmunosorbent test, Radiosensitivity test, RAST test, Reinsch's test, Reverse CAMP test, Rey test, RF-rheumatoid factor test, Rickettsia antibody test, Rinne test, Romberg test, Rose-Waaler test, Rothera's (nitroprusside) test, RPR test, Rubin test, Sabin-Feldman dye test, Saccharin test, Scheffé's test, Schick test, Schiller's test, Schilling test, Schirmer's test, Schwabach's test, Scotchtape™ test, Screening test, Seashore test, Secretin injection test, Seleny test, Seliwanoff's test, Sentinel™ urine HIV-1 test, Serial sevens test, Serologic test, Serologic test for syphilis, Serum neutralization test, Sherlock Holmes test, Sickle cell test, Simple test, Sims-Huhner test, Sink-or-float test, SISI test, Skin test, 'Sort of' test, Special test, Spot test, Standard acid reflux test, Standard of care test, Statistical test, Stenger test, Stimulation test, Stratified log-rank test, Stress test, String test, Stroop test, Student's 't' test, Substantial capacity test, Substantial factor test, Sucrose hemolysis test, Super stress test, Suppression test, Sweat test, Swinging flashlight test, Tensilon test, Thallium stress test, Thematic apperception–See TAT test, Thenar weakness test, Thörmahlen test, Three glass test, Thrombin time test, Thromboplastin generation test, Thyroid suppression test, Thyroid function test, Tilt test, Time manual performance test, Tolerance test, Tone decay test, Total catecholamine test, Tourniquet test, Trail-making test, TRAx CD4 test, Treponema pallidum hemagglutination test, Treponema pallidum immobilization test, TRH stimulation test, Triple test, TRUE test, Trypan blue dye exclusion test, Tryptophan loading test, TSH stimulation test, Tubeless test, Tuberculin skin test, Tuberculosis test, Tukey test, Turing test, Turbidity test, TWEAK test, Twin-to-twin transfusion test, Two-tailed test, Tzanck test, Uni-Gold HIV test, Urea breath test, Urease test, Urecholine supersensitivity test, Urine concentration test, Urecholine sensitivity test, Van der Bergh test, VDRL test, Vestibular test, Viral load test, Vitamin K test, Vocabulary test, Voges-Proskauer test, Volhard's test, Wada test, Waived test, Washout test, Wassermann test, Water deprivation test, Watson-Schwartz test, Weber test, Wechsler test, Weil-Felix test, Whiff test, Whiskey test, Widal's test, Wilcoxon's rank-sum test, Wipe test, Wisconsin Card-Sorting test, Wonderlic Personnel test, Word association test, WRAT test, Xylose absorption test, 14C-Xylose test, Y chromosome test. Vox populi The process of putting a product through exercises that simulate its anticipated use, to identify differences between its actual and expected behavior. See Beta testing.
testtrial/experiment assisting diagnosis
Allen's test test of arterial occlusion in the foot, i.e. leg elevation (until plantar skin blanches and Doppler sound at dorsalis pedis [DP] pulse is lost) followed by compression of DP pulse (by clinician's thumb) and lowering of leg to dependency; if posterior tibial artery flow is adequate the foot rapidly resumes its normal colour; test is repeated at posterior tibial pulse, to test patency of DP
anterior drawer test; ADT; Lachman's test test of stability/integrity of lateral collateral ligaments of ankle joint, i.e. flex knee to >45° (to relax posterior muscle group), stabilize lower tibia (with one hand) whilst grasping posterior aspect of patient's heel (with the other); calcaneum is pulled forward as a simultaneous retrograde force is applied to lower tibia; positive ADT = > 4mm anterior displacement of foot relative to tibia together with positive ‘suction sign’
Buerger's test test of arterial status of lower limb, i.e. patient reclines supine on couch; leg is elevated (from hip) for 1 minute (whilst patient alternately dorsi- and plantarflexes ankle joint, to drain venous circulation); limb is lowered to dependency or patient stands up (foot shows brief hyperaemia before returning to normal skin colour); time (in seconds) for normal colour return is noted; >20 seconds = inadequate arterial supply; >40 seconds = severe limb ischaemia; note: clinician should note whether cyanosis (rather than brief hyperaemia) occurs on dependency, and duration of cyanosis; persistent dusky red/purple coloration in dependent limb that appears to resolve to normal skin tone on raising limb to horizontal indicates severe arterial compromise
Clarke's test diagnostic test of chondromalcia patellae; with the patient supine and the affected knee fully extended, the clinician applies gentle pressure to the patella whilst the patient attempts to contract the quadriceps muscle group; the test is positive if severe patellar pain occurs
Coombs test test to predict donor and receiver blood compatibility, i.e. assay for presence/absence of specific antibodies on donor erythrocytes
coordination tests tests of cerebellar coordination of lower-limb motor function, i.e. heel–shin test; fingertip test
fingertip test test of cerebellar function, i.e. patient repeatedly attempts to place his/her fingertip on tip of assessor's moving finger; alternatively, patient attempts to put tip of his/her index finger alternately on his/her nose then on assessor's moving finger
glass test test for meningitis, i.e. test is positive when there is no blanching of a pruritic rash when it is pressed with a glass
glucose tolerance test; GTT diagnostic test of diabetes mellitus, and assessment of patients with fasting blood glucose levels just above normal range (i.e. 5.6–6.7 mmol/L), i.e. 75mg glucose is given (as a drink) after starving for 12–14 hours; its rate of blood clearance is monitored over the next 3 hours; in normal patients, there is an immediate and sharp rise in blood glucose which falls during subsequent 2 hours to normal glycaemic levels (i.e. 2.9–5.9 mmol/L); in diabetes/insulin resistance cases, blood glucose levels rise initially to a higher level and do not return to normal range within 2 hours
Heaf test test of immunity to tubercle bacillus (tuberculosis [TB]), i.e. subdermal injection of attenuated tuberculin toxin
heel–shin test test of cerebellar function, i.e. patient repeatedly places one heel on anterior aspect of other shin and slides heel down to dorsum of foot; inability to perform this test indicates cerebellar dysfunction and other conditions characterized by loss of motor coordination
interdigital test reduced blunt/sharp discrimination, paraesthesia, hyper-/hypoaesthesia of interdigital skin at toe cleft affected by neuritis/Morton's neuroma
Jack's test passive dorsiflexion of hallux at first metatarsophalangeal joint in weight-bearing foot
Kelikian push-up test intraoperative check of adequate surgical correction of lesser-toe deformity, i.e. elevation of head of relevant metatarsal with thumb pressure
Mantoux test, tuberculin test screening test for exposure to tuberculosis (TB); administration of an intradermal dose of tuberculosis antigen (tuberculin) to the skin of the forearm; a localised, small, firm inflammatory skin reaction developing within 2 days shows positive exposure to tuberculosis
Mulder's test diagnostic test for Morton's neuroma, i.e. simultaneous lateral compression across metatarsal heads + thumb pressure at affected plantar web space in a foot with symptoms of plantar digital neuritis (Morton's neuroma); positive result (i.e. induction of characteristic symptoms of a nerve entrapment pain, and examiner's awareness of a fluid thrill [or click] within the palpated tissue) indicates neuritis or neuroma
Nobel's test test for iliotibial band (ITB) syndrome, i.e. palpation of lateral tibial condyle causes ITB pain
Ober's test test for iliotibial band (ITB) syndrome, i.e. excessive tightness/tension on palpation of the ITB
patch test; skin test test of hypersensitivity, i.e. application of a range of potential sensitizing agents to skin (e.g. back, ulnar aspect of arm); degree of inflammatory reaction (provoked by test agents) is compared with a control (innocuous substance) and ‘read’/assessed after 48–96 hours
pole test test to estimate foot systolic pressures in limbs with arterial calcification, i.e. with patient supine, leg is elevated until Doppler foot pulses cease, and elevation height (in cm) from apex of hallux to bench is noted and multiplied by 7.35
Romberg's test test comparing amount of body sway of an erect patient with eyes closed and eyes open; test is positive if patient shows loss of balance/increased tendency to sway when standing with eyes closed
screening test any test that categorizes by predetermined characteristic/property
single-leg raise test; tiptoe test test of tendo Achilles (TA), tibialis posterior and peroneal integrity/function, i.e. patient stands on one leg and weight-bears on tiptoe; patient with TA damage will not be able to rise normally to tiptoe on affected side; with TA rupture, patient will not be able to rise up on to tiptoe on the affected limb at all; heel pain during single-leg raise is indicative of Sever's disease see sever's
talar tilt test test of integrity of lateral collateral ligament of the ankle, calcaneofibular ligament and tibialis posterior tendon, i.e. with the ankle joint at neutral (0° dorsiflexion) the calcaneum is passively inverted by the examiner; if the lateral collateral ligament is damaged (e.g. anterior talofibular ligament rupture) excessive talar excursion occurs; tissue dimpling inferior to the lateral malleolus indicates rupture of the calcaneofibular ligament; greater than expected talar eversion and flattening of the medial longitudinal arch indicate tibialis dysfunction
Thompson's test test of Achilles tendon function, i.e. with the patient lying prone, the posterior calf muscle group is squeezed, causing ankle joint plantarflexion; the foot does not plantarflex in total Achilles tendon rupture
thumb roll test test for ‘runner's knee’, i.e. the knee is flexed by 30–40° and the examiner's thumb rolled across the medial aspect of the patella, causing a painful ‘snap’ or ‘click’, and detection of a fibrous ridge/‘shelf’ at anterior knee compartment
Trendelenburg's test test of the quality of venous filling time, and quality of venous drainage in the leg, i.e. carried out as Buerger's test, but the time (in seconds) taken for the dorsal foot veins to refill and the direction of blood flow into the dorsal foot veins is noted; refill from proximal to distal indicates venous backflow and vein valve incompetence
Tuberculin test see Mantoux test
urea breath test test to detect Helicobacter pylori gastritis, or confirm its eradication, i.e. by analysis of exhaled breath
Valsalva's test test to detect autonomic neuropathy, i.e. the patient exhales into an empty plastic syringe (the other end of which is connected to a manometer to be maintained at 40mmHg) for 10 seconds, and changes in heart rate are noted (i.e. maximum expiratory heart rate and minimum heart rate after test cessation), and compared as a ratio; ratio of <1:10 indicates autonomic neuropathy (normal = >1:21)
vertical stress test test of plantar plate rupture, i.e. application of vertical stress to metatarsal head; translocation (i.e. > 2mm dorsal elevation) of base of toe in relation to dorsum of metatarsal head indicates plantar plate rupture
vibration test test of peripheral sensory function (assessing pacinian corpuscle function), i.e. application of vibration stimuli (from activated 128Hz tuning fork or neuraesthesiometer) to bony prominences (e.g. medial aspect of first metatarsophalangeal joint, lateral aspect of fifth metatarsal styloid process, medial and lateral malleoli, tibial tuberosity); vibrational awareness is reduced in the elderly and may be lost in diabetic distal sensory neuropathy, correlating with reduced pain awareness
Salmonella bacteria, and the rate of mutations is noted so as to determine the carcinogenicity of the substance.
anterior compression test, ilial compression test, or
ilial rocking test.
2., test used to discern the bilateral extension of the sacrum from bilateral flexion.
after-image test A subjective test used to determine the presence or absence of abnormal retinal correspondence (ARC). The subject is instructed to fixate the centre of a vertical light filament for some 15 s with one eye and then the centre of a horizontal light filament for some 15 s with the other eye. Looking at the after-images of the two filaments on a uniform surface (e.g. a wall) the subject sees either a cross, which indicates normal retinal correspondence or two separated filaments, indicating ARC. Syn. Hering's after-image test. See after-image; abnormal retinal correspondence.
after-image transfer test Test aimed at detecting and measuring the angle of eccentric fixation in an amblyopic eye in a patient with normal retinal correspondence. The normal eye fixates an illuminated vertical line and is then occluded, while the amblyopic eye fixates a dot. If the after-image and the fixation point coincide the amblyopic eye has no eccentric fixation, otherwise the relative position of one to the other indicates the angle of eccentric fixation. Syn. Brock's after-image test. See eccentric fixation; retinal corresponding points.
alternate cover test See cover test.
Ammann's test See neutral density filter test.
Arden grating test A clinical test for contrast sensitivity. It consists of photographic plates, each with a sinusoidal grating of constant spatial frequency but of increasing contrast from top to bottom. There are seven plates, one being for demonstration. The other six, each with a different spatial frequency, are used for testing. The spatial frequencies are: 0.2, 0.4, 0.8, 1.6, 3.2 and 6.4 cycles per degree when viewed at a distance of 50 cm. Contrast levels are numbered from 1 to 20 on a vertical scale on the side of the plate. The testing procedure consists of slowly removing each plate from its folder until the grating becomes visible to the patient, at which point the contrast level is noted. The testing is carried out monocularly with optical correction, if any. The procedure is repeated for each plate and all the contrast levels are added to arrive at a score, which is compared with normal values provided in the instructions. Syn. Arden gratings; Arden plates. See contrast sensitivity chart; contrast sensitivity function; Vistech.
Bagolini's lens t . A test to detect binocular sensory and motor anomalies such as abnormal retinal correspondence and suppression. Two Bagolini lenses, one in front of each eye with their striations oriented 90º apart (typically 135º for one eye, 45º for the other) are used. The patient fixates a punctate light source at distance and near. Each eye sees a diagonal line perpendicular to that seen by the fellow eye. For example, if one line, or part of one line, is missing there is suppression. If the two diagonal lines cross at the source the patient is orthophoric or if strabismic, as indicated by the cover test, the patient has harmonious abnormal retinal correspondence (Fig. T3). Syn. Bagolini's striated lens test. See Bagolini's glass.
balancing test A test designed to obtain equal focusing or equal accommodative states in the two eyes. This is accomplished either objectively (by retinoscopy) or, more commonly, subjectively using either the duochrome test, or comparing the visual acuity in the two eyes simultaneously or successively, or using prisms to present two images of a chart and ask the patient to compare these images, or using a binocular refraction technique (e.g. Turville infinity balance test). Syn. equalization test. See binocular balance; Humphriss method; vectogram.
bar reading test A test for determining the presence of binocular vision and also used in the management of amblyopia in which a narrow bar (or a pencil) is held vertically between the reader's eyes and a page of print. The bar occludes a vertical strip of print but the strip is different for the two eyes and if binocular vision is present the subject will experience no difficulty reading the text. Syn. Welland's test.
basic secretion test Measurement of the basal tear secretion independently of reflex tear secretion. A filter paper strip (e.g. Whatman No. 41) is placed in the anaesthetized lower fornix, and after five minutes the strip is removed and the amount of wetting measured from the folded end. See tear secretion; Schirmer's test.
Bielschowsky's head tilt test A test to determine which of the inferior or superior extraocular muscles and of which eye is paretic. The test is based on the following fact: if the head is tilted to the right, the right intorters of the right eye (superior oblique and superior rectus muscles) contract as well as the extorters of the left eye (inferior oblique and inferior rectus muscles). If the head is tilted to the left, the inferior oblique and inferior rectus muscles of the right eye contract to cause extorsion while the superior oblique and superior rectus of the eye contract to cause intorsion. Thus, tilting the head towards one side will indicate the palsied muscle. For example, in the right superior rectus muscle palsy, when the head is tilted to the left there will be no change in the vertical deviation, since contraction of the right superior rectus muscle is not involved. However, when the head is tilted to the right there will be an increase in downward movement. This test is not reliable in an adult with congenital ocular palsy. See forced duction test; three-step test.
Bielchowsky's phenomenon t . A test used to differentiate between dissociated vertical deviation (DVD) and alternating hypertropia. After the occlusion of one eye (which elevates behind the cover) a wedge of increasing density is placed in front of the fixating eye; if the patient has DVD the eye behind the cover will perform a gradual downward movement with increasing filter density and a gradual upward movement if the wedge is moved in the opposite direction. Syn dark wedge test. See dissociated vertical deviation; Bielchowsky's phenomenon.
blind test See single-blind study; double-blind study.
blue field entoptoscope test See blue field entoptoscope.
blur back test See plus 1.00 D blur test.
break-up time test (BUT) A test for assessing the precorneal tear film. Fluorescein is applied to the bulbar conjunctiva and the patient is asked to blink once or twice and then to refrain from blinking. The tear film is scanned through the slit-lamp using a cobalt blue filter with a wide beam, while the examiner counts or records the time between the last blink and the appearance of the first dry black spot which indicates that the tear film is breaking up. In normal subjects, break-up times vary between 15 and 35 s (in Caucasians). A BUT of 10 s or less is abnormal and may be due to mucin deficiency, and is often considered to be a negative factor for success in contact lens wear, especially soft lenses. However, this test has been shown to be flawed, because fluorescein can disrupt the tear film. See precorneal film; cobalt lens; mucin; non-invasive break-up time test.
broad H test A test to evaluate the integrity of the extraocular muscles and their innervation. The patient is asked to fixate a penlight while keeping the head still. The penlight is moved slowly horizontally to one side of the straight ahead position, then moved vertically, back down to the horizontal line, then below it and back up again to the horizontal line. The penlight is now moved along the horizontal line to the other side of the straight-ahead position and the same procedure is repeated thus completing the shape of the letter with a wide horizontal dimension. Overaction or underaction of one eye and the patient's report of diplopia in any position of gaze are recorded to identify the paretic muscle/s. See motility test.
Brock's after-image test See after-image transfer test.
Brock's string test See Brock's string.
Bruckner's test See Bruckner's method.
Cardiff acuity test A test for measuring the visual acuity of young children. It is composed of a series of cards, each with a different picture (either a car, a dog, a duck, a fish, a house or a train) drawn with a white band, which is surrounded by a black line half the width of the white, on a neutral grey background. Thus the average luminance of the target is equal to that of the grey background. The picture is situated either in the top or bottom half of the card. The pictures remain of the same overall size on each card; only the width of the black and white bands decreases in size. There are 11 acuity levels ranging from 6/60 (20/200) to 6/6 (20/20) at a viewing distance of 1 metre, in 0.1 log steps. The acuity is given by the narrowest white band for which the picture is still recognizable, but the child's eye movements are also noted to confirm or establish recognition. This test is best used with toddlers and children with intellectual impairment (Fig. T4). See preferential looking method.
City University colour vision test A set of 10 pseudoisochromatic plates, each consisting of a central coloured spot surrounded by four differently coloured spots. The subject is asked to choose the spot that most closely matches the colour of the central spot in each plate viewed at a normal reading distance. For each plate there is a normal response and a response corresponding to each of the colour defects, deutan, protan and tritan. See Farnsworth test.
test chart See test chart.
colour vision test See Edridge-Green lantern; pseudoisochromatic plates; City University colour vision test; Farnsworth test; lantern test; wool test.
confrontation test A rough method of determining the approximate extent of the visual field. The patient, with one eye occluded, faces the examiner at a distance of about 60 cm and fixates the opposite eye of the examiner. The test object is moved in a plane midway between the examiner and the patient, starting far in the periphery and moving it towards the patient and in various meridians until it is seen.
contrast sensitivity test See contrast sensitivity chart; contrast sensitivity function; contrast sensitivity; Arden grating test; Vistech.
corneal reflex test See Hirschberg's method; Javal's method; Krimsky's method.
cortical vision screening t . (CORVIST) A test designed to detect visuoperceptual impairments caused by a cerebral disease (e.g. Alzheimer, stroke) or injury, in individuals who have normal or near-normal vision (with or without correction). It consists of an A4-size bound book containing a sequence of ten cards, each one assessing a different aspect of visual processing by cortical centres, and prefaced by a description of its aim, instructions and significance. The test includes symbol acuity, shape discrimination, size discrimination, shape detection, hue discrimination, scattered dot counting, fragmented numbers, word reading, crowding and face perception.
cotton thread test See phenol red cotton thread test.
cover t . (CT) A test for determining the presence and the type of heterophoria or strabismus. The subject fixates a small letter or any fine detail at a given distance. Strabismus is usually tested first. The opaque cover or occluder is placed over one eye and then removed, while the examiner observes the other eye and then the same operation is repeated on the other eye (this is called the unilateral cover test). If neither uncovered eye moves, the subject does not have strabismus. If the unoccluded eye moves when a cover is placed in front of the other, strabismus is present. In esotropia the unoccluded eye will move temporally to take up fixation, while in exotropia the unoccluded eye will move nasally, and an upward or downward movement indicates hypotropia or hypertropia, respectively. In alternating squint, in which either eye can take up fixation, the eye behind the cover will appear deviated when uncovered and will move as the cover is shifted to the other eye.The type of heterophoria can be detected by observing the eye behind the cover. If there is no movement of the eye behind the cover, the subject is orthophoric. If the eye behind the cover moves inward, and outward when the cover is removed, the subject has esophoria. If the eye behind the cover moves outward, and inward when the cover is removed, the subject has exophoria. A similar procedure is used for hyperphoria and hypophoria. As it is difficult to view the eye behind the cover without allowing sufficient peripheral fusion to stop the eyes going to the phoria position, the observer usually watches for the recovery movement as the occluder is removed. By placing prisms of increasing power in front of one of the eyes until no movement is evoked, one can evaluate the approximate amount of the phoria. The cover test is the only objective method of measuring heterophoria. The determination of the magnitude of the deviation of the strabismus or heterophoria can also be done with the alternate (alternating) cover test (ACT). The subject fixates a target and the cover is successively placed in front of one eye and then the other while watching the eye that has just been uncovered to see the direction of the deviation. The amount of deviation can be estimated by using prisms of appropriate strength and base direction until the movement of the eye is neutralized when the cover is alternated from one eye to the other (prism cover test).Although these tests are objective, they are sometimes used subjectively, i.e. the patient indicates the apparent movement of the fixation object. The alternate cover test is the most appropriate test for subjective testing. An apparent movement of the fixation object in the same direction as the cover indicates exophoria, while an apparent movement of the fixation object in the opposite direction to the cover indicates esophoria. An apparent downward movement of the fixation indicates hyperphoria of the eye from which the occluder is moved. Again prisms can be placed in front of the eyes until the apparent movement disappears, thus giving a measure of the heterophoria. This subjective perception of a movement of a stationary fixation object in people with heterophoria or strabismus is a particular example of the phi phenomenon. Syn. occlusion test; screen test.
cross-cylinder test for astigmatism A subjective test for measuring the axis and the amount of astigmatism using a cross-cylinder lens. Having obtained the best visual acuity with a spherical lens, the cross-cylinder lens is placed before the eye being tested with its axes at 45º to the cylinder axis determined by retinoscopy. The patient looks at a single circular target, often a letter (O or C or Verhoeff's circles), the cross-cylinder lens is then flipped and if one position provides a clearer image of the target, the axis of the correcting (minus) cylinder should be turned towards the minus axis of the cross-cylinder lens until vision is equally blurred in both positions of the cross-cylinder lens. That point indicates the correct axis of the correcting cylinder. The determination of the power of the correcting cylinder is carried out by placing the cross-cylinder lens with one of its axes parallel to the axis of the correcting cylinder. The cross-cylinder lens is flipped and the position that provides the clearer vision indicates whether to increase the cylinder power (when the minus axis of the cross-cylinder is parallel) or decrease cylinder power (when the plus axis is parallel). The proper amount of cylinder correction is obtained when the vision is equally blurred in both positions of the cross-cylinder lens. Syn. cross-cylinder method; cross-cylinder test; Jackson crossed cylinder test.
cross-cylinder test at near A subjective test to determine the addition for near vision. It is performed (monocularly or binocularly) at a distance of usually 40 cm with the patient wearing his or her subjectively determined lenses and cross-cylinder lenses with axes horizontal and vertical and viewing a test chart composed of parallel, horizontal and vertical black lines. Beginning with sufficient fogging lens power, the plus lens power is reduced until the patient reports that the vertical and horizontal lines are equally distinct. See addition; fogging method.
dark filter test See neutral density filter test.
dark room test See provocative test.
dark wedge test See Bielchowsky's phenomenon test.
Denver Developmental Screening test See developmental and perceptual screening test.
development and perceptual screening test A test used to assess children's perceptual and processing skills, such as gross motor coordination, directionality, laterality, visual form perception, visual memory and visualization, visual-motor integration and auditory and language development. There are many such tests, each evaluating one or several of the above skills. The most common ones are: (1) The Denver Developmental Screening Test (DDST), which is used for children up to about six years of age. It is easy to administer and covers a wide range of skills, which fall into four sectors: personal-social, fine motor-adaptive, language and gross motor. Treatment and/or referral will depend on the type of skills found to be abnormal. (2) The Test of Visual Analysis Skills (TVAS) assesses the child's visual perceptual skills. It consists of 18 squares containing dots and lines, each forming a different pattern. The child is given a pencil and a special test form on which to reproduce the visual stimuli. The test comes with an expected score for each grade up to grade 3 and failure to reach that score may indicate that the child has a perceptual skills disorder. (3) The Gardner Reversal-Frequency Test in which the child is asked to mark those letters and numbers which are printed backward. This test assesses the directionality skill.
developmental eye movement test (DEM) An indirect test for saccadic eye movements in which the subject reads numbers placed in four vertical columns (total of 80 numbers) and 16 horizontal rows (total of 80 numbers). The lengths of time taken to perform the horizontal and the vertical subtests are measured independently and assessed as a ratio, as well as the number of errors (omissions, additions, transpositions, or substitutions). All results are compared to test norms for the age of the subject. The vertical array mainly gives an indication of visual-verbal number skills (automaticity), whereas the horizontal array provides additional information on oculomotor function.
differential intraocular pressure test A test for differentiating between a muscle paresis and a mechanical restriction of the eye. The intraocular pressure is measured in the primary position and then again with the patient turning his or her eyes in the direction of action of the suspected paretic muscle. An increase in intraocular pressure of 6 mmHg or more indicates a mechanical restriction (e.g. a fracture of the orbital floor), whereas no change in pressure suggests a muscle paresis. This test produces less discomfort to the patient than the forced duction test. See forced duction test.
diplopia test 1. A test for measuring heterophoria in which the fusion reflex is prevented by displacing the retinal image of one eye with a prism as in the von Graefe's test in which the magnitude of the phoria is estimated by the amount of prism necessary to align the two images. To measure lateral phorias the images are displaced vertically and aligned one above the other, whereas to measure vertical phorias the images are displaced horizontally and realigned horizontally (if a phoria is present). Syn. displacement test; prism dissociation test. 2. A test to investigate the integrity of the extraocular muscles in strabismus, in which the patient is required to view a light source in the dark with a red filter in front of one eye and a green filter in front of the other, to produce diplopia (prisms are sometimes necessary). The direction and extent of diplopia are evaluated relative to the size and direction of the angle measured with the cover test at the same distance. See dissociation; red-glass test.
displacement test See diplopia test.
dissociating test Any test for measuring heterophoria in which fusion is dissociated. See dissociation; Maddox rod; diplopia test.
distortion test A test for measuring heterophoria, in which the images presented to the two eyes are so unlike that they cannot be fused. The most common such test is the Maddox rod test.
doll's head test See doll's head phenomenon.
Dolman's test See hole in the card test.
double-blind test See double-blind study.
double prism test A test for determining the presence of cyclophoria, in which a double prism (a pair of prisms set base to base) with the base line horizontal is placed before one eye. The patient is requested to fixate a horizontal line (or row of letters), which through the double prism appears as two lines (or two rows) vertically separated. On uncovering the other eye, the patient sees three lines (or rows). If there is no cyclophoria, all three lines (or rows) will appear parallel, but lack of parallelism indicates cyclophoria. The double prism used in this test consists of two weak prisms (about 4 or 5 Χ): this clinical type of double prism is commonly called a Mad dox double prism (Fig. T5). See Fresnel's bi-prism; Maddox rod test.
Dunlop test A test for determining motor ocular dominance. It consists in having the eyes fusing two slightly different targets in, for example, a synoptophore, and diverging the targets until diplopia appears. Just beforehand, fixation disparity occurs in one eye. That eye is called the non-dominant or non-reference eye. The other eye is the dominant or reference eye.
duochrome test A subjective refraction test in which the subject compares the sharpness of black targets (e.g. Landolt rings) of similar sizes, on a red background on one side and on a green background on the other side (blue is sometimes used) of a chart. In undercorrected myopia or overcorrected hyperopia, the letters on the red background will appear more distinct, while in overcorrected myopia or undercorrected hyperopia the letters on the green background will appear more distinct, and in emmetropia or corrected ametropia the letters should appear equally distinct on both sides. The test makes use of the chromatic aberration of the eye and assumes that when the eye is looking at distant objects it is focused on the yellow part of the visible spectrum. Syn. bichrome test; duochrome method. See cobalt lens; Verhoeff's circles.
dye dilution test A test for detecting a blockage in the lacrimal (or drainage) system. It consists of instilling a few drops of fluorescein (or a mixture of rose bengal and fluorescein) into the conjunctival sac and observing how long it takes before it dilutes which is shown by the change in colour. No change in colour indicates a blockage or a lack of tear production. See lacrimal apparatus; fluorescein staining; Jones 1 test.
'E' test See 'E' game; illiterate E chart.
equalization test See balancing test.
Esterman test A method of quantifying visual field disability. It consists of a grid made up of rectangles of different sizes placed across the field, being smaller centrally, inferiorly and along the horizontal meridian than at other locations, as these areas are considered to be most important functionally. Each rectangle contains a dot in the centre. There is a grid for the monocular field with 100 rectangles and a grid for the binocular field with 120 rectangles. The grid is placed on top of the results of the field chart. A percentage score is calculated on the basis of the number of spots seen by the patient. The grids are incorporated into most automated perimeters.
fan and block test A test for determining the axis and the amount of astigmatism of the eye. It consists of an astigmatic fan chart with an inner rotating central disc on which are printed an arrowhead forming an acute angle of typically 60º and two sets of mutually perpendicular lines or 'blocks'. The test follows the subjective determination of the best vision sphere that places the circle of least confusion on the retina. A positive spherical lens, of a power equal to half the estimated amount of astigmatism, is placed in front of the eye to create simple myopic astigmatism. The patient is asked to indicate the clearest line(s) on the chart and the arrowhead is rotated until its two sides appear equally blurred. The axis of the correcting negative cylindrical lens is then read on the fan chart. The amount of astigmatism is found when that cylindrical lens is of a power such that the two blocks appear equally clear. Syn. fan and block method. See astigmatic fan chart; fogging method.
Farnsworth test A colour vision test consisting of 85 small discs made up of Munsell colours of approximately equal chroma and value, but of different hue for normal observers. The examinee must place the discs so that they appear in a continuous and smooth series. Errors are scored and a diagnosis of the type and severity of the colour defect can be made. A smaller version of the Farnsworth test called the Farnsworth D-15 exists (Figs. T6 and T7). It consists of only 15 small discs and the procedure is the same, but it is a more rapid test, which does not give as much information as the large version. However, it has been found to be very valuable for detecting severe colour vision defects, including tritanopia. There exist also some versions of this test in which the colour samples are less saturated than the standard ones: (1) The Lanthony desaturated D-15 test in which the colour samples are less saturated by 2 units of Munsell chroma but also lighter by 3 units of Munsell value than the standard D-15 test, and (2) the Adams desaturated D-15 test in which only the saturation (or chroma) has been reduced by 2 units. These desaturated D-15 tests are more effective in detecting mild colour vision deficiencies than the standard D-15 test. Syn. Farnsworth-Munsell 100 Hue test (or FM 100 Hue test). See defective colour vision; Macbeth lamp; Munsell colour system; City University colour vision test.
Farnsworth-Munsell 100 Hue test See Farnsworth test.
fluorescein test 1. A test to assess the fit of hard contact lenses. Fluorescein is instilled between the cornea and the contact lens and under ultraviolet illumination areas where the lens touches the cornea appear purple or blue, whereas areas where there is a space between the lens and the cornea appear yellowish green. This appearance is often referred to as fluorescein pattern. 2. Test using fluorescein and ultraviolet illumination to detect abrasions or other corneal epithelial defects, which stain yellowish green. See apical bearing; Burton lamp; rose bengal; staining; Jones 1 test; Jones 1 test.
fogging test See fogging method.
forced duction test A test for differentiating between a muscle paresis and a mechanical restriction of the eye. The eye in which the conjunctiva is anaesthetized is grasped with toothless forceps and passively rotated in the direction of action of the suspected paretic muscle. If the eye cannot be rotated further than the point where the patient can voluntarily rotate it, a mechanical restriction exists (e.g. a fracture of the orbital floor): if the examiner can passively rotate the eye to its full extent, the muscle is paretic. Syn. traction test. See paralysis of the third nerve; strabismus fixus; Brown's superior oblique tendon sheath syndrome; Bielschowsky's head tilt test; three-step test.
four dot test See Worth's four dot test.
four prism dioptre base-out test A test for the detection of microstrabismus (microtropia) and for the assessment of the suppression area. A 4 Χ BO is placed momentarily in front of the fixating eye (or the eye with the best acuity) and if the other eye moves outward but does not refixate inward it indicates suppression in that eye and a small angle strabismus. Microstrabismus is also indicated if, when the prism is placed BO in front of the eye that showed suppression, there is no movement of either eye. The extent of the suppression area can be assessed by momentarily placing prisms, of various powers and in various directions, in front of the affected eye until diplopia is noticed. The observation of the patient's eye movements is difficult because of the small angle of deviation and because of the variation in size of the suppression area. Syn. Irvine's prism displacement test. See microtropia.
FRIEND test A subjective test for simultaneous binocular vision in which the word FRIEND printed with the letters FIN in green and RED in red is viewed through red and green filters, one before each eye. People with simultaneous binocular vision see all the letters, whereas those with suppression see only some of the letters. See Worth's four dot test.
Frisby stereo t . See Frisby stereotest.
Gardner Reversal-Frequency test See test, developmental and perceptual screening.
gradient test See AC/A ratio.
von Graefe's test See diplopia test.
Hering after-image test See after-image test.
Hess-Lancaster test A test for measuring and classifying strabismus using the Hess screen.
Hirschberg's test See Hirschberg's method.
hole in the card test A test for determining which eye is dominant. It consists of a card with a hole in it, through which the patient views a spotlight (or a letter) on a distant test chart while holding the card with both hands. The eye that the patient uses to view the letter is the dominant eye. This is easily detected by having the patient occlude each eye in turn and when the dominant eye is covered the spotlight can no longer be seen through the hole. Syn. Dolman's test. See ocular dominance; manoptoscope.
hole in the hand test A test for binocular vision in which a distant object is viewed through a tube with one eye while a hand is placed against the tube at a distance of some 20-30 cm before the other eye. Subjects who see the object through an apparent hole in the hand have binocular vision, whereas seeing either the object through the tube only or the hand only indicates an absence of binocular vision. Syn. hole in the hand illusion.
Holmgren's test See wool test.
Howard-Dolman test A test for measuring stereoscopic visual acuity consisting of two black vertical rods on a white background, viewed through an aperture from a distance of 6 m. By means of a double cord pulley arrangement, the subject manipulates one of the rods until it appears in the same plane as the fixed rod. The distance between the two rods is then measured, and calculations must be made to arrive at the acuity. See three-needle test; two-dimensional test.
Humphriss immediate contrast test See Humphriss method.
infinity balance test See Turville infinity balance test.
Irvine's prism displacement test See four-prism dioptre base-out test.
Ishihara test See pseudoiso-chromatic plates.
Jackson crossed cylinder test See cross-cylinder test for astigmatism.
Jones 1 test A test to evaluate the tear drainage system. Fluorescein dye is instilled into the conjunctival sac. Over a period of five minutes at one-minute intervals, a cotton-tipped applicator is placed under the anaesthetized inferior nasal turbinate. Absence of dye suggests a blockage somewhere in the passage, the nasolacrimal duct being the most common site. Jones 2 test may then be performed. Syn. fluorescein instillation test; primary Jones test.
Jones 2 test After Jones 1 test, fluorescein is washed out and physiological saline is injected into the anaesthetized lower canaliculus. If the fluid recovered from the nose is fluorescein-stained the test is positive indicating a partial obstruction in the nasolacrimal duct, otherwise there is a blockage in the punctum, canaliculus or common canaliculus or a defective pumping mechanism of the tears. See lacrimal apparatus; dye dilution test.
Krimsky's test See Krimsky's method.
Lang test See Lang stereotest.
lantern test An occupational colour vision test used mainly to evaluate recognition of aviation and maritime signals. There are several such tests (e.g. Edridge-Green lantern, Giles-Archer lantern, Holmes-Wright lantern, Farnsworth lantern or Falant). The latter two show colours in pairs of which there are nine and the observer's task is to name the colours.
light-stress test See photostress test.
log MAR crowded test See Glasgow acuity cards.
Maddox rod test 1. See Maddox rod. 2. A test for measuring cyclophoria in which a Maddox rod is placed in front of each eye, with axes parallel, while the subject views a spot light through a 10 to 15 Χ prism (to displace one image relative to the other). The subject will then see two streaks. If they appear parallel there is no cyclophoria. If not, one of the Maddox rods is rotated slowly until the subject reports that the two streaks are parallel. The angle of rotation as determined with a protractor scale indicates the amount of cyclophoria. See double-prism test.
Maddox wing test See Maddox wing.
Mallett test See Mallett fixation disparity unit.
manoptoscope test See manoptoscope.
motility test A test aimed at investigating the integrity of the extraocular muscles and their innervation. The most common method is to have the patient fixate a penlight, which is moved in eight meridians while keeping the head still: up, up and to the right, right, down and to the right, down, down and to the left, left, up and to the left, following a star pattern. The test can be done either binocularly or monocularly. Such movements will test the action of all six extraocular muscles of both eyes. If, for example, the penlight is moved up and to the right of the patient, any limitation in movement indicates a fault in either the right superior rectus or the left inferior oblique muscle (Fig. T8). See pursuit movement; yoke muscles; A pattern; V pattern; cardinal positions of gaze; diagnostic positions of gaze; broad H test; red-glass test.
neutral density filter test A test to differentiate between functional and organic amblyopia by measuring visual acuity, with or without a neutral density filter. If acuity is greatly reduced when looking through the filter, the amblyopia is organic (e.g. glaucoma, central retinal lesions), but if the acuity is unaffected or even slightly improved, the amblyopia is functional. The validity of this test has been questioned. Syn. Ammann's test; dark filter test.
New Aniseikonia test A test for measuring aniseikonia. It consists of a booklet with pairs of half-moons, one green, the other red, and of different sizes. The patient wears red and green filters and is asked to point to the set of half-moons that appear to have identical vertical diameters. If the sizes are actually equal the patient has no vertical aniseikonia; if the sizes are actually unequal the patient has vertical aniseikonia of a percentage amount indicated next to the target. The booklet is rotated to a horizontal position to measure the horizontal aniseikonia.
non-invasive break-up time test (NIBUT) A test that does not require any interference with the eye used for assessing the stability of the precorneal tear film. The patient's head rests on a chin rest at the centre of a hemispherical bowl of 20 cm radius, which is attached at the apex to a binocular microscope. A grid of white lines on a matt black background is inscribed on the inner surface of the bowl and the image of this grid pattern projected onto the open eye is observed. The subject fixates a hole in the centre of the grid pattern and refrains from blinking. The time taken for the appearance of the first randomly distributed distortion or discontinuity of some of the reflected grid lines is a measure of the precorneal tear film break-up. The values for normal subjects vary between 5 and 200 seconds with a mean of around 40 seconds. The instrument used to measure NIBUT is often referred to as a toposcope. See Tearscope plus; break-up time test.
Norn's test A test for assessing tear secretion. It consists of instilling one drop of a mixture of 1% fluorescein and 1% rose bengal into the lower conjunctival sac. After five minutes a slit-lamp examination is made of the colour of the stain in the central portion of the tear meniscus along the lower lid. The colour may be compared either with known dilutions of the mixture in capillary tubes or simply classified into five colours: intense red, pale red, intense orange, weak orange and yellow. In normal eyes the colour is yellow or weak orange whereas in a dry eye it is red. Syn. tear dilution test. See dry eye; keratoconjunctivitis sicca; break-up time test; non-invasive break-up time test; phenol red cotton thread test; Schirmer's test.
test object See test type.
ocular ferning test A test for the assessment of ocular mucus. Conjunctival scraping are placed on a glass slide, left to dry and examined under the microscope for the presence or absence of arborization (fernlike pattern). Normal eyes show ferning whereas in patients with cicatrizing conjunctivitis, such as ocular pemphigoid or Stevens-Johnson syndrome, ferning of the mucus is reduced or absent. See cicatricial pemphigoid.
optokinetic nystagmus test (OKN) A test for eliciting OKN. The subject sits in front of a rotating drum covered with uniform black and white vertical stripes parallel to the axis of rotation (this apparatus is called an optokinetoscope or optokinetic drum). When the eyes respond with a slow movement in the same direction as the drum lasting about 0.2 s, and a fast phase in the reverse direction of about 0.1 s, the OKN has been elicited and this fact provides evidence of vision. As finer and finer black and white stripes are used, this reflex response will cease to be elicited for a particular spatial frequency of the stripes corresponding to the objective visual acuity of the subject (Fig. T9). See malingering; nystagmus.
Parks three-step t . See three-step test.
Pepper test A test for assessing reading performance in low vision patients. It emphasizes the visual rather than the cognitive component of reading. Thus, each chart consists of unrelated letters and words, rather than continuous text. Each row contains either separate letters (at the top of the chart) or separate words (of increasing length in the lower portion of the chart), all of the same size. Missing the first or last half of the word indicates the position of the scotoma relative to the fixation point. The rows at the top of the chart are triple line spaced, they are double line spaced in the middle and single line spaced at the bottom, thus requiring more and more exacting saccadic eye movements. There are five charts, each of different sized print. A reading rate, such as the number of correct units read per minute, can be determined with this test. Syn. Pepper Visual Skills for Reading Test (VSRT).
phenol red cotton thread test A test for measuring tear secretion. It is accomplished by using a special cotton thread, impregnated with phenol red dye. The thread is inserted under the lower eyelid for 15 seconds, and both eyes are closed. The absorption of tears is determined by the length of thread that has turned from red to yellow (due to the pH of tears). The average length varies between 3 and 48 mm, and less than 9 mm is usually indicative of a dry eye. This test is much quicker and much less uncomfortable than Schirmer's test and has good reliability. However, questions have been raised as to whether it is the actual secretion rate that is being measured. There exist several cotton thread tests to measure tear secretion, using different cottons of different lengths and diameters and some are used without phenol red dye. See tear secretion; Norn's test; Schirmer's test.
phi phenomenon test of Verhoeff See phi movement.
photostress test A test to differentiate the cause of a reduced visual acuity in one eye, between a lesion in the optic nerve and a disease in the fundus of the eye. A bright light is directed into the eye with the best acuity, for 10 seconds, while the defective eye is covered. The light is then removed and the patient is instructed to read the line just above the best visual acuity line for that eye. The time taken until the patient can just read that line is recorded. The same procedure is then repeated with the defective eye. If the recovery time is about the same in both eyes, the cause of the reduced visual acuity is an optic nerve lesion (e.g. retrobulbar optic neuritis); if the recovery time is much longer for the defective eye the cause is in the fundus (e.g. retinal oedema, retinopathy, age-related macular degeneration). The latter is attributed to a delay in the regeneration of visual pigments after being bleached with a bright light. Syn. light-stress test.
pinhole test See pinhole disc.
plus 1.00 D blur test A check test used to verify a patient's spherical correction or to determine whether a person is hyperopic. It consists of placing a +1.00 D lens in front of the eye: visual acuity should be reduced from 6/6 (20/20) to about 6/18 (20/60). If the patient can still read smaller letters than 6/18, the spherical prescription is incorrect or the patient is hyperopic. This result could also be due to a much smaller pupil than average. This test is most helpful with young children as it helps relax accommodation. Syn. blur back test. See absolute hyperopia; fogging method.
prism adaptation test A prognostic test in cases of esotropia (convergent strabismus), indicating whether surgical intervention is favourable or not. Prior to the intervention, the patient has to wear a BO prism, of an amount larger than the angle of deviation, for an hour or more. An increase in the angle of deviation is an unfavourable prognosis and no increase or a decrease is considered favourable.
prism cover test See cover test.
prism dissociation test See diplopia test.
prism reflex test See Krimsky's method.
prone position test See provocative test.
provocative test A test performed to reproduce signs of a suspected disease in order to help in the diagnosis of that disease. A common provocative test for open-angle glaucoma is the water-drinking test in which a fasting patient has to drink one quart of water (or about 1 litre in a 70 kg adult) within five minutes. The intraocular pressure (IOP) is measured before the water is taken and then at 15-minute intervals. An increase of 8 mmHg or more in 45 minutes is considered positive. Two common provocative tests for angle-closure glaucoma are: (1) The dark room test in which the patient is kept in a dark room for 1 hour and the IOP is measured before and after the test. An increase of 8 mmHg or more is generally considered positive. (2) The prone position test in which the patient lies in the prone position for 1 hour and if the IOP increases by 8 mmHg or more, compared with the value before the test, the result is considered positive. In open-angle glaucoma provocative tests have been found to be positive in less than half of the patients but that figure is higher in angle-closure glaucoma.
Purkinje tree test See angioscotoma.
push-up test 1. See method, push-up. 2. A procedure used to ensure adequate lens movement of a soft contact lens. The lens is gently pushed upward by pressing on the patient's lower eyelid: it should move easily and return quickly to its original location.
random-dot E test See random-dot stereogram.
Raubitschek test See Raubitschek chart.
red glass test A test for determining diplopia or suppression in which a bright target (e.g. a white light) is fixated while a red filter is held in front of one eye to interrupt fusion. The patient with diplopia will see a red light and a white light. The amount of deviation can be estimated by using a prism of an amount such that it eliminates the double image. The operation can be repeated in all the diagnostic positions of gaze to help identify a paretic extraocular muscle as the distance between the two images increases in the field of action of the paretic muscle. If only one light is seen it indicates suppression of one retinal image. Syn. red filter test. See primary action; diplopia test; motility test.
Scheiner's test A test for measuring the monocular near point of accommodation. It consists of using a Scheiner's disc in front of the eye, which observes a small target such as a thin black line. The target is moved towards the eye until it is no longer seen single. That point represents the near point of accommodation. See Scheiner's experiment.
Schirmer's test A test for measuring tear secretion. It is accomplished by using a 35 ✕ 5 mm strip of filter paper (e.g. Whatman No. 41). The filter strip is folded so that one end, about 5 mm long, is inserted at the mid-portion (or lateral portion) of the lower eyelid of a patient seated in a dimly lit room. Tear secretion is considered normal if 10 mm or more of the paper from the point of the fold becomes wet in a four-minute period. More than 25 mm of wetting would indicate excessive tear secretion. Without any additional stimulation of any kind the test, called Schirmer's test 1, measures mainly the basal tear production, but because the filter paper tends to irritate the conjunctiva, some of the reflex tear secretion may be also be measured as well. Schirmer's test 2 is aimed at measuring mainly reflex tear secretion. It is carried out with the filter paper inserted inside the lower lid of an eye with topical anaesthesia, while the contralateral half of the nasal mucosa is irritated by rubbing it with a dry cotton-tipped applicator. The amount of tear production is measured after two minutes. A value of more than 15 mm is considered to be normal and less than 15 mm may indicate a deficiency of reflex tear secretion (Fig. T10). See alacrima; keratoconjunctivitis sicca; tear secretion; Norn's test; phenol red cotton thread test.
screen test See cover test.
sessile drop test Measurement of the contact angle by observation of the formation of a drop of liquid on a solid surface. The image of the droplet may be photographed or projected. See contact angle.
shadow test 1. A test that gives an approximate evaluation of the depth of the anterior chamber. It is carried out by placing a penlight on the temporal side of the eye at the level of the pupil and directing the beam of light horizontally towards the inner side of the eye. If the iris lies in a flat plane, which usually indicates a deep anterior chamber, the entire iris will be illuminated. If the iris is directed anteriorly, which usually indicates a narrow anterior chamber, the iris on the temporal side of the eye will be illuminated but the iris on the nasal side will be shadowed to varying degrees depending on the narrowness of the anterior chamber (Fig. T11). Syn. oblique illumination shadow test. 2. See retinoscopy. 3. A test for the homogeneity of a lens (both material and surface quality) in which the light from a small, intense source of light passes through the lens and falls on a screen. Any defects will show as shadows. See angle of the anterior chamber; Shaffer and Schwartz van Herick method; Smith's method.
Sheridan-Gardiner test A visual acuity test consisting of a large card (called the key card) which is held by the patient who is asked to point to the letter on that key card that is the same as the letter shown on the distance (or near) chart. The test consists of several cards with single letters of various sizes. It is most useful for testing children and illiterates.
Simultan test See Simultantest.
stereotest test See Frisby stereotest; Lang stereotest; vectogram.
swinging flashlight test See Marcus Gunn pupil.
test target See test type.
tear test See impression cytology; rose bengal; basic secretion test; break-up time test; non-invasive break-up time test; ocular ferning test; phenol red cotton thread test; Schirmer's test.
tear dilution test See Norn's test.
Thorington test A test for the measurement of heterophoria at near and at distance. It consists of a horizontal row of letters on one side of a light source and a horizontal row of numbers on the other side of that source. A Maddox rod, orientated horizontally, is placed in front of one eye and the patient who is fixating the light source is asked to report through which letter or number the vertical streak appears to pass, or to which it is closest. At 6 m the number of letters must be placed 6 cm apart to represent 1 Χ steps. If the Maddox rod is in front of the right eye, the numbers on the right side of the source and the letters on the left, each number represents 1 Χ of esophoria and each letter represents 1 Χ of exophoria. The Thorington test can also be used at near. At 40 cm, for example, the separation of the letters and numbers must be 0.4 cm to represent 1 Χ. It can also be placed vertically with the Maddox rod orientated vertically to measure vertical heterophoria.
three-dimensional test See two-dimensional test.
three-needle test A test for measuring stereoscopic visual acuity consisting of three fine rods placed vertically, two of them being fixed in the same plane, while the third one is movable in between. The subject views them through an aperture. The centre rod is placed in various positions backward and forward until the subject judges whether it is nearer or farther than the others (Fig. T12). See stereopsis; Howard-Dolman test.
three-step test An objective test for determining which extraocular muscle is paretic in a patient with hypertropia. A three-step procedure is used: (1) to determine the type of hypertropia (right or left); (2) to determine the magnitude of the hypertropia (e.g. with prisms and cover test) when the patient fixates to the right and to the left; (3) to determine the magnitude of the hypertropia when the head is tilted towards each shoulder. Each step in this procedure reduces the number of possible muscles involved until it points to only one muscle of one eye. Example: paresis of the left superior oblique. Step (1) a left hypertropia points to a paresis of one of the following four muscles: left superior oblique, left inferior rectus, right inferior oblique or right superior rectus. Step (2) a hypertropia of the left eye increases when fixating to the right points to a paresis of either the left superior oblique or the right superior rectus. Step (3) a hypertropia of the left eye which increases when the head tilts to the left, points to a paresis of the left superior oblique. Syn. Parks three-step test. See Bielschowsky's head tilt test; forced duction test.
Titmus stereo test See vectogram.
Turville infinity balance test (TIB) A test for balancing the accommodative state of the eyes. It can also be used for detecting suppression, vertical and horizontal associated phorias and (with a target composed of two horizontal lines) aniseikonia in the vertical meridian. It consists of a 3 c+m-wide vertical septum placed in the centre of a mirror on which is reflected a reversed illuminated chart. Thus the patient can only see the right side of the chart with the right eye, and the left side with the left eye, which allows for simultaneous comparison of the chart seen by both eyes, while still retaining fusion for peripheral objects near the border of the chart. If the chart is projected onto a screen, the septum is placed halfway between patient and screen. The test is carried out after the conventional refractive procedures. Syn. infinity balance test. See binocular balance; associated heterophoria; suppression; balancing test.
two-dimensional test A test for stereopsis consisting of two-dimensional objects as test material such as targets, cards, etc. as used in a stereoscope or a major amblyoscope (e.g. random-test stereogram; Titmus stereotest). Other tests for stereopsis are three-dimensional (3-D), the Howard-Dolman test being the most well known. Two-dimensional tests (2-D) are the most commonly used in clinical practice. See random-dot stereogram; stereoscope; stereo-test; Howard-Dolman test; vectogram.
test type Any letter, figure or character used for vision testing. The term test object (Syn. test target) is a more general term, which encompasses any pattern or object (e.g. checkerboard, grating). See chart; grating; Jaeger test type; König bars; Landolt ring; optotype; checkerboard pattern.
phi phenomenon test See phi movement.
test of Visual Analysis Skills See developmental and perceptual screening test.
water-drinking test See provocative test.
Welland's test See bar reading test.
wool test A test for assessing colour vision deficiencies. It consists of a set of wool strands, which are to be matched with loose wool strands of the same colour. The best-known of these is the Holmgren's test. Syn. colour wool test.
Worth's four dot test A test for determining the presence of binocular vision. It consists of four illuminated discs: two green, one red and one white on a black background. The test is viewed at any distance by a subject wearing red and green filters such that one eye sees the red and the white discs, while the other eye sees the two green discs and the white disc. Subjects are asked to report how many dots they see: four dots indicates normal binocular vision; two dots, both red, indicates suppression of the image in the eye wearing the green filter; three dots, all green, indicates suppression of the image in the eye wearing the red filter; and five dots, two red and three green, indicates diplopia. Syn. four-dot test. See suppression; FRIEND test; Worth's classification of binocular vision.
Somogyi units, defined as the amount of amylase needed to digest 1.5 g of starch in 8 minutes at 37°C. The normal range is 60 to 200 units/100 ml. The serum amylase is also elevated in mumps and other diseases of the salivary glands.
sensation: apply gentle touch, pinpricks, or warm or cold objects to areas supplied by the nerve and note responses; (2)
reflex: try the jaw jerk and eye and sneeze reflexes; (3)
motor function: test the patient's ability to chew and work against resistance and observe contraction of the masseter and temporal muscles by visual examination and digital palpation.
Histoplasma capsulatum. A positive test indicates past or present infection (histoplasmosis).
Treponema pallidum immobilization tests.
Treponema pallidum by specific antibodies in the serum of an infected individual; not widely used.
Treponema pallidum or extracts from a treponeme as antigen. Included are
T. pallidum immobilization (TPI),
T. pallidum agglutination (TPA), fluorescent treponemal antibody (FTA), Reiter protein complement-fixation (RPCF), and
T. pallidum complement-fixation (TPCF) tests.