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The chart was designed by Ian Bailey [5] and Jan E. Lovie-Kitchin at the National Vision Research Institute of Australia. [1] [3] They described their motivation for designing the LogMAR chart as follows: "We have designed a series of near vision charts in which the typeface, size progression, size range, number of words per row and spacings were chosen in an endeavour to achieve a ...
Figure 1 - Humphrey field analyser. Humphrey field analyser (HFA) is a tool for measuring the human visual field that is commonly used by optometrists, orthoptists and ophthalmologists, particularly for detecting monocular visual field.
After-image transfer ALT: Alternating ALT ET/SOT: Alternating esotropia: ALT XT/XOT: Alternating exotropia ARC: Anomalous retinal correspondence A/V: Arteriole–venue ratio BIO: Binocular indirect ophthalmoscopy BSV: Binocular single vision: BV: Binocular vision: BVD: Back vertex distance BVP: Back vertex power CD: Centration distance C/D: Cup ...
These two images are later used together to create a 3D image. In this way the image can be analysed giving better information about surface characteristics of the retina. [19] Fundus photography in animals: Fundus photography is a useful tool utilised for veterinary research, veterinary ophthalmology, as well as education. [20]
In geometric optics, distortion is a deviation from rectilinear projection; a projection in which straight lines in a scene remain straight in an image.It is a form of optical aberration that may be distinguished from other aberrations such as spherical aberration, coma, chromatic aberration, field curvature, and astigmatism in a sense that these impact the image sharpness without changing an ...
By measuring this zone, the autorefractor can determine when a patient's eye properly focuses an image. The instrument changes its magnification until the image comes into focus. The process is repeated in at least three meridians of the eye and the autorefractor calculates the refraction of the eye, sphere, cylinder and axis.
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Visual acuity is the eyes ability to detect fine details and is the quantitative measure of the eye's ability to see an in-focus image at a certain distance. The standard definition of normal visual acuity (20/20 or 6/6 vision) is the ability to resolve a spatial pattern separated by a visual angle of one minute of arc.