VISUAL acuity is determined by the smallest angle at which the eye is able to distinguish two points as separate. It is therefore inversely proportional to the minimum visual angle. The normal visual acuity is found to correspond to an average minimum visual angle of one minute. Thus with relatively small angles one may say that the visual acuity is inversely proportional to the space which sep...

BACKGROUND Visual acuity measurement often results in an imprecise endpoint because subjects correctly identify some but not all of the letters on one or more size levels on a letter chart. The extent of this transition zone from seeing to nonseeing can be described by probit size, which is calculated by performing Probit Analysis on letter chart data. There has been no previous research into t...

Recent reports have described marked improvement of visual acuity in amblyopic eyes of young children following monocular exposure to square-wave gratings presented at a variety of spatial frequencies and orientations for as little as 7 minutes. We sought to confirm and expand on these investigations, with emphasis on single-session results. Sixteen juvenile and 11 adult amblyopes and 26 contro...

AIM To offer a critique of current methods of defining amblyopia treatment outcome and to examine alternative approaches. METHOD Literature appraisal and descriptive case presentations. RESULTS Currently, the outcome of amblyopia treatment is expressed as the number of acuity chart lines gained or, alternatively, achievement of an arbitrarily adopted level of visual acuity. As binocular vis...

Our purpose was to compare reading performance measured with the MNREAD Acuity Chart and an iPad application (app) version of the same test for both normally sighted and low-vision participants. Our methods included 165 participants with normal vision and 43 participants with low vision tested on the standard printed MNREAD and on the iPad app version of the test. Maximum Reading Speed, Critica...

'Indian' numerals, which are popular among the Arab population, were used to devise a new Snellen's visual acuity chart. The new chart has the advantages of a reading chart. It keeps the patient's interest, does not miss alexic patients, and is quicker to perform. It is also devoid of the many disadvantages of a kinetic response chart (the capital E letter or Landolt's broken rings), especially...

AIM The purpose of this study was to compare near visual acuity of dentists without optical aids (VSC) with near visual acuity of those using the Galilean telescope system (VGA2) with magnification of x 2.5, and the distance of 350 mm in simulated clinical conditions. METHODS The study included 46 dentists (visual acuity 1.0 without correction). A visual acuity testing was carried out using a...

BACKGROUND Following excimer laser photorefractive keratectomy (PRK), an increase in glare sensitivity and a reduction in contrast sensitivity can occur owing to changes in the cornea (structure and topography). In this study, an attempt was made to quantify and document objectively a change in those subjective perceptual factors. METHODS Snellen visual acuity and disability glare were measur...