method(redirected from Callahan's method)
Also found in: Dictionary, Thesaurus, Legal, Encyclopedia.
See also: fixative, operation, procedure, stain, technique.
methodThe manner in which a particular thing is performed.
methodMedtalk The manner in which a particular thing is performed. See Cold turkey method, Comparative method, Confidence profile method, Confirmation method, Contrast-enhanced method, Delphi method, Designated comparison method, Diary method, Direct fluorescent antibody method, Empirical method, Heuristic method, Immunoperoxidase method, Micro method, Natural experiment method, Parametric method, Pisano method, Reference method, Rhythm method, Sandwich method, Shotgun method, Socratic method, Street intercept method, Substitute method, Time sampling method, Unproven method for cancer management, Valid method, Validated method, Westergren method.
See also: fixative, operation, procedure, stain, technique
Bruckner's method An objective method of detecting the presence of strabismus. The examiner illuminates both eyes of the patient simultaneously with an ophthalmoscope from a distance of about 1 metre. Looking through the ophthalmoscope the examiner focuses on the fundus reflexes seen in the two pupils. If one pupil appears brighter it is considered that this eye may be strabismic and perhaps amblyopic. The reason may be due to the fact that this eye will be deviated and optical aberrations will make the pupil area appear brighter and whiter. The examiner may also note the position of the corneal reflexes when carrying out this test. This test is more reliable when patients are wearing their correction. Syn. Bruckner's test. See Hirschberg's method.
cross-cylinder method See cross-cylinder test for astigmatism.
Donders' method See push-up method.
Drysdale's method A method that has been applied for the determination of the radius of curvature of hard contact lenses. The principle consists of placing a light source in a modified microscope in focus at the surface of the lens and at the centre of curvature of the surface, the distance between the two being recorded on a dial as the radius of curvature. See back optic zone radius; Radiuscope.
duochrome method See duochrome test.
fogging method Method of relaxing accommodation during the subjective measurement of ametropia. This is achieved by placing enough plus lens power (or less minus lens power) in front of an eye to form an image in front of the retina. In this condition, any effort to accommodate will produce a poorer image and relaxation of accommodation is thus achieved (Fig. M8). Then, plus lens power is decreased (or minus lens power increased) until the patient reports no further improvement in visual acuity. This point represents the maximum positive lens power (or minimum negative lens power) and it is called the best vision sphere (BVS). See refractive error; fan and block test; plus 1.00 D blur test.
von Graefe's method See diplopia test.
van Herick, Shaffer and Schwartz method A technique for estimating the angle of the anterior chamber. It is based on the fact that the width of the angle of the anterior chamber is correlated to the distance between the posterior corneal surface and the anterior iris as viewed near the corneal limbus. This is done using a slit-lamp with a narrow slit beam perpendicular to the temporal or nasal corneal surface, viewing from the straight-ahead position and comparing the depth of the anterior chamber to the thickness of the cornea. If the AC depth is equal to or greater than the corneal thickness, the angle is considered to be grade 4 (corresponding to a wide open angle). If the AC depth is equal to one-half the corneal thickness, the angle is considered to be grade 3 (this is the most common angle width). If the AC depth is equal to one-fourth the corneal thickness, it is considered to be grade 2, and if the AC depth is less than one-fourth the corneal thickness, it is considered to be grade 1 (corresponding to a very narrow angle). Grade 0 is considered to be a closed angle. The method is most useful for predicting the possibility of angle-closure glaucoma. The results of this method are in good agreement with those of the Shaffer classification using a gonioscope. Syn. van Herick's technique. See gonioscopy; shadow test.
Hirschberg's method Method for estimating the objective angle of strabismus. The examiner's eye is placed directly above a small penlight source fixated by the subject and observes the position of the corneal reflex of the deviating eye. The angle of strabismus can be estimated on the basis that each mm of deviation, relative to the corneal reflex in the fixating eye, represents approximately 7º (12 Χ) of strabismus (Fig. M9). Syn. Hirschberg's test. See Bruckner's method; Krimsky's method.
Humphriss method Method of binocular subjective refraction in which the eye not being refracted is blurred by means of a +0.75 D (or +1.0 D) spherical lens above the correcting lens. This lens produces a suppression of foveal vision while allowing peripheral fusion to maintain binocular alignment of the two eyes during refinement of the correction to the other eye. Syn. Humphriss immediate contrast test (HIC). However, HIC differs somewhat from the above method because it relates only to one specific procedure: a +0.25 D sphere is followed by a −0.25 D sphere in front of the unfogged eye and the patient has to indicate which is the clearest. The above method can be used for many types of refractive procedures. See refractive error; balancing test.
Javal's method Method for determining the objective angle of strabismus using a perimeter. The patient is seated before a perimeter arc with the deviating eye at the centre of the arc while the other eye fixates a distant point straight ahead. The examiner moves both a light source and his eye directly above it, until the corneal reflex appears centred in the entrance pupil of the deviating eye. The position of the source on the arc can be read to give the objective angle of strabismus. Angle lambda must be added in convergent and subtracted in divergent strabismus as the criterion used was the pupillary axis, which makes an angle with the line of sight. Strictly speaking, angle kappa, rather than lambda, should be taken into account. See angle of deviation.
Krimsky's method Method used to determine the objective angle of strabismus. The examiner's own eye is placed directly above a small penlight source fixated by the subject and observes the position of the corneal reflexes. Prisms are placed in front of the deviating eye until the examiner finds the prism power that makes the corneal reflex appear to occupy the same relative position as that in the fixating eye. Syn. prism reflex test. See Hirschberg's method.
minus lens method Method of measuring the monocular amplitude of accommodation which consists in placing minus lenses in front of one eye while the subject fixates the smallest optotypes (usually subtending about one minute of arc, that is the 6/6 or 20/20 line). Progressively stronger lenses are used until the patient reports that the test appears blurred. The determination of the amplitude must take into account the vergence at the eye of the fixation point and the test must be carried out with the patient's distance correction. If the minus lens to blur is −4 D and the fixation distance 40 cm, the amplitude will be equal to 6.5 D. See subjective accommodation.
preferential looking method (PL) A method of assessing visual acuity in infants. It consists of presenting two stimuli on a uniform background, one of which contains a pattern (e.g. a checkerboard or a grating) and the other a plain field of equal shape, size and luminance, and observing the infant's eyes. If the infant can resolve the pattern he or she tends to fixate that stimulus for a larger percentage of time. By reducing the size of the detail in the pattern, a threshold can be obtained when the infant fixates at either stimulus for the same length of time. See objective visual acuity; Teller acuity cards; Cardiff acuity test.
push-out method See push-up method.
push-up method Method of determining the near point of accommodation by moving a test object (made up of small optotypes subtending one minute of arc (that is the 6/6 or 20/20 line) at the eye and uniformly illuminated) closer to the patient's eye. It is usually done monocularly and then binocularly. The near point is achieved when the small test object yields a sustained blur and not just begins to blur. Alternatively, the card is moved back after appearing blurred until the small test object just appears to clear again. This is often called the push-out method. In older patients, plus lenses may be needed to carry out the test and the power of the lens is subtracted from the reading. The amplitude of accommodation is deduced by taking into account the vergence at the eye of the far point (it is at infinity in emmetropes and corrected ametropes). Syn. Donders' method. See amplitude of accommodation; near point rule.
Smith's method A method of estimating the depth of the anterior chamber. It is performed with a conventional slit-lamp. The angle between the illumination beam and the microscope, which is placed along the straight-ahead position, is set at 60º. To examine the patient's right eye the examiner looks through the right eyepiece and through the left eyepiece to examine the left eye. A beam of moderate thickness is oriented horizontally and focused on the cornea. Two horizontal images of the slit will appear separated by a dark space one sharply focused corresponding to the cornea and the other out of focus corresponding to the anterior lens surface. The slit is lengthened until the two separate reflections just touch. At this point the length of the slit is measured and multiplied by a factor of 1.4 to arrive at an estimate of the depth of the anterior chamber. The method gives optimum results within the range of 1.4 mm and 3 mm. It is most useful in assessing shallow chambers as this could lead to angle-closure glaucoma. See shadow test.
method of stabilizing the retinal image See stabilized retinal image.
Patient discussion about method
Q. What are the screening methods for autism? I have a friend who has an autistic child. My daughter is 5 months old and I was wondering if there are any screening methods that help determine autism.
Q. I was wondering is there any method to keep her in control? My 11 year old daughter is very impulsive. She will not let others speak. She talks to everyone irrespective of whether she knows them or not. Sometimes I have also noted that she blabbers something without her knowledge. I can understand that she is having ADHD but how do others know that she suffers from ADHD? Though I am guiding her positively, it is hard for her to remember these instructions. She is very impulsive that she acts immediately. She lacks good sleep as may be needed for the kids of her age. I was wondering is there any method to keep her in control?
Q. What Are the Methods of Terminating a Pregnancy? What ways are there today to end an unwanted pregnancy?