منابع مشابه
How to measure distance visual acuity
Procedure • Ensure good natural light or illumination on the chart. It is important to ensure that the person has the best possible chance of seeing and reading the test chart as treatment decisions are made based on the results of VA testing. • If the test is done outdoors, the chart should be in bright light and the patient in the shade, with enough light to illuminate the patient’s face duri...
متن کاملScreening for Significant Refractive Error Using a Combination of Distance Visual Acuity and Near Visual Acuity
PURPOSE To explore the effectiveness of using a series of tests combining near visual acuity (NVA) and distance visual acuity (DVA) for large-scale screenings for significant refractive error (SRE) in primary school children. METHOD Each participant underwent DVA, NVA and cycloplegic autorefraction measurements. SREs, including high myopia, high hyperopia and high astigmatism were analyzed. C...
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This study examined the quantitative relationship between foveal visual acuity and contrast sensitivity for large-letter optotypes in a group of patients with retinitis pigmentosa (RP), in order to assess more completely the extent of foveal vision loss in this group of hereditary retinal dystrophies. High-contrast visual acuity and large-letter contrast sensitivity were measured with a compute...
متن کاملVisual Acuity and Comfortable Distance from a Display
The image perception in humans depends on many factors. One of the most important ones is certainly the observing distance. The distance from which human look at the images is important for studying image perception in general and in particular on display devices. This paper describes a method of measurement of the preferred observing distance among humans of different age, sex, etc. under cont...
متن کاملSpatial frequency sweep pattern reversal VER acuity vs Snellen visual acuity: Effect of optical defocus
The effect of artificially induced image defocusing on visual acuities (VAs) measured by spatial frequency sweep pattern reversal visual evoked response (SPVER) and Snellen measurement was studied in six normal subjects. The steady-state SPVER was recorded using vertical gratings of 10 different spatial frequencies ranging from 0.52 to 30.36 c/deg. The SPVER acuity was compared with Snellen acu...
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ژورنال
عنوان ژورنال: Ophthalmic and Physiological Optics
سال: 2008
ISSN: 0275-5408,1475-1313
DOI: 10.1111/j.1475-1313.2008.00584.x