axial length of the eye

length of the eye, axial

The distance between the anterior and posterior poles of the eye. In vivo, it is measured either by ultrasonography or by partial coherence interferometry (PCI). These measurements represent the distance between the anterior pole and Bruch's membrane. (In young eyes in which there is a refractive index difference at the retina-vitreous interface ultrasonography measures the distance between the anterior pole and the anterior surface of the retina.) The axial length of the eye at birth is approximately 17 mm and reaches approximately 24 mm in adulthood. It is typically longer than 24 mm in myopes and shorter than 24 mm in hyperopes. Each mm of change in axial length of the eye corresponds to approximately 2.5 D See biometry of the eye; ultrasonography.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
Frequency Distribution of Respondents based on the Axial Length of the Eye Treated with Toric Multifocal IOL Axial length of Eyes Frequency of Eyes Percentage (%) of Eyes 20-22 mm 3 7.5 22-24 mm 28 70.0 24-26 mm 9 22.5 Total 40 100.0 Table 4.
Conclusions: Retinal nerve fibre layer thickness measurements were found to vary with refractive status and axial length of the eye. Ocular magnification significantly affected the retinal nerve fibre layer thickness, and it should be considered in diagnosing glaucoma.
While the exact mechanism of this association is not well recognized, some theories have been proposed, as "light-dopamine theory," which stated that the exposure to the sunlight during outdoor activities stimulate the release of dopamine neurotransmitter from the retina which has been suggested to have the ability to inhibit elongation of the axial length of the eye [18, 34, 35].
An Icare[R] rebound tonometer (TA01, TIOLAT Oy, Finland) was used to measure intraocular pressure (IOP); compound tropicamide eye drops (SANTEN OY, Tampere, Finland) were applied to dilate the pupil; a direct ophthalmoscope was used to observe the vertical cup-to-disc ratio (C/D) and the posterior pole of both eyes; for the glaucoma suspect patients, especially the infant patients, a fundus photograph would be obtained by Retcam (Clarity Medical Systems, Pleasanton, CA, USA) for C/D observation, a flashlight was used to examine the cornea, a Type A ultrasound test was used to evaluate the axial length of the eye, and gonioscopy would be applied to glaucoma suspect patients.
Concluding the current findings, the development of degenerative lesions in the ocular fundus is associated both with the elongation of the axial length of the eye, and with worsening of blood flow.
In a later session dedicated to myopia, fellow American optometrist, Tom Aller, emphasised the significant role soft bifocal contact lenses (both centre-distance and centre-near designs, with adds of up to +2.00D), have in reducing myopia progression in children, with significantly lower increases in axial length of the eye. The work of Earl Smith, medical director at TMF, on how peripheral hyperopic defocus drives myopia progression was highlighted, along with the effect of simultaneous vision contact lenses in reducing this to help reduce myopia progression by up to 38%.
Regarding choice of IOL power calculating formula, the Royal College of Ophthalmologists' recommended IOL calculation formulae depending on the axial length of the eye.
(4.) Sherpa D, Badhu BP Association between axial length of the eye and primary angle closure glaucoma Kathmandu University Medical Journal (2008), Vol.
Biometry requires measurement of the axial length of the eye and the corneal curvature together with an appropriate computer formula to predict IOL power.
The axial length of the eye (EL), age, and sex were not associated with any postoperative parameters.