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Purpose: Current chart‐based tests of spatial contrast sensitivity (SCS) with fixed or narrow frequency ranges (≤18 cycles/°) cannot characterise the limits of spatial contrast vision. Here we present the design and validation of a chart‐based measure of the spatial contrast envelope. Methods: Following the principles of the standard visual acuity (Bailey‐Lovie) and contrast sensitivity (Pelli‐Robson) charts, a combined spatial‐contrast and visual acuity chart was designed using a language‐independent triangular symbol for a four‐alternative forced‐choice procedure plus chart rotation. Symbol frequencies ranged between 0.38 and 60 cycles/° spaced along 10 radial axes (0.55%–100% contrast). The chart was validated with reference to the Bailey‐Lovie and Pelli‐Robson charts; its reliability and sensitivity to changes in illumination, simulated cataract and blur was evaluated in healthy adults. Results: The photopic SCS function could be measured in 5.5 ± 0.5 min; thresholding around the spatial contrast resolution limit reduced completion times to ~2 min. There was good agreement with high‐contrast visual acuity (difference = 0.08 ± 0.02 logMAR) and contrast‐sensitivity at 1.5 cycles/° (0.13 ± 0.06 logCS). Test‐retest reliability was excellent at all spatial frequencies (ICC = 0.99). Mesopic illumination or simulated cataract caused a generalised SCS loss; myopic blur reduced high‐frequency sensitivity. Spatial contrast sensitivity was independent of radial axis orientation (cardinal or oblique). Conclusions: The chart provides a time‐efficient, reliable and inexpensive measure of SCS with applications in research and clinic for detecting subtle deficits in early stages of ocular and neurological conditions that often manifest at higher frequencies. It is sensitive to vision changes occurring in dim lighting and with simulated cataract and blur. The chart is available open‐access for self‐printing; contrast variation in print can be controlled through user calibration and/or establishing normative SCS functions using the theoretical values. [ABSTRACT FROM AUTHOR]

Purpose Evaluation of a new personal-computer-based vision test aimed for rapid and accurate assessment of macular conditions such as age-related macular degeneration ( AMD). Methods The new test depends on segmented digits defined by rarebits, that is, receptive field-size bright dots briefly presented against a dark background. Digit size was fixed at 40 × 50 min of arc. Digit positions were varied at random within a 4.6 × 3.5-degree test field. There were no fixation demands. The number of rarebits per digit segment could be varied between 3 (the minimum needed for veridical perception) and 128, in 11 preset steps. The test task was to find the smallest rarebit number required to recognize the test digits. Thirty-seven patients with various stages of AMD and 25 control subjects participated in the evaluation, which also included a standard acuity test. Results Analysis of receiver operating characteristics indicated significantly better discrimination by the rarebit test. Rarebit numbers >16 appeared to reliably indicate the presence of oedema. Conclusion The rarebit test appeared well suited for fine grading of vision in AMD. The simple set-up and the lack of fixation demands made for practicable examinations of short durations. The test is available for free on the Internet. [ABSTRACT FROM AUTHOR]

As part of the National Institutes of Health Toolbox initiative, we developed a low-cost, easy-to-administer, and time-efficient test of vestibular and visual function. A computerized test of dynamic visual acuity (cDVA) was used to measure the difference in visual acuity between head still and moving in yaw. Participants included 318 individuals, aged 3 to 85 years (301 without and 17 with vestibular pathology). Adults used Early Treatment of Diabetic Retinopathy Study (ETDRS) optotypes; children used ETDRS, Lea, and HOTV optotypes. Bithermal calorics, rotational chair, and light box testing were used to validate the cDVA. Analysis revealed that the cDVA test is reliable for static (intraclass correlation coefficient [ICC] >/=­ 0.64) and dynamic (ICC >/= 0.43--V0.75) visual acuity. Children younger than 6 years old were more likely to complete cDVA with Lea optotypes, but reliability and correlation with ETDRS was better using HOTV optotypes. The high correlation between static acuity and light box test scores (r = 0.795), significant difference of cDVA scores between those with and without pathology (p >/=­ 0.04), and the good to excellent sensitivity (73%) and specificity (69%) establish that the cDVA is a valid and reliable measure of visual acuity when the head is still and moving, as well as a good proxy of vestibular function to yaw rotation. [ABSTRACT FROM AUTHOR]

In this study we evaluated the immediate effectiveness of an optoelectronic visual field expander in a sample of subjects with retinitis pigmentosa suffering from a severe peripheral visual field restriction. The aid uses the augmented view concept and provides subjects with visual information from outside their visual field. The tests were carried out in daylight conditions. The optoelectronic aid comprises a FPGA (real-time video processor), a wide-angle mini camera and a transparent see-through head-mounted display. This optoelectronic aid is called SERBA (Sistema Electro-óptico Reconfigurable de Ayuda para Baja Visión). We previously showed that, without compromising residual vision, the SERBA system provides information about objects within an area about three times greater on average than the remaining visual field of the subjects [1]. In this paper we address the effects of the device on mobility under daylight conditions with and without SERBA. The participants were six subjects with retinitis pigmentosa. In this mobility test, better results were obtained when subjects were wearing the SERBA system; specifically, both the number of contacts with low-level obstacles and mobility errors decreased significantly. A longer training period with the device might improve its usefulness. [ABSTRACT FROM AUTHOR]

Aim: To design and validate a Turkish version of the MNREAD acuity charts. Materials and methods: A vocabulary was created using high-frequency words that appear in Turkish schoolbooks used by 8-year-old children in the third grade. In total, 125 sentences were generated. The sentences were read by 2 groups (20 adults and 20 primary school students), and reading time and verbal mistakes were recorded. Thereafter, persistent verbal mistakes and sentences with extreme high and low mean reading speeds were excluded. Finally, the validity of the participants' reading speed as measured with the MNREAD Turkish version was determined by comparing it to their reading speed for daily reading tasks. Results: Reading speed for text of 1.6 M print size (logMAR 0.6) was 185.10 ± 20.46 words/min, reading speed for text of 1 M print size (logMAR 0.4) was 185.45 ± 27.27 words/min, and the maximum reading speeds calculated using the MNREAD Turkish version were 191.50 ± 32.19 words/min for chart 1 and 190.55 ± 27.35 words/min for chart 2. As expected, correlations were observed between chart 1 and chart 2 (r = 0.88, P < 0.01), between chart 1 and logMAR 0.6 text (r = 0.74, P < 0.01), between chart 1 and logMAR 0.4 text (r = 0.67, P < 0.01), between chart 2 and logMAR 0.6 text (r = 0.63, P < 0.01), and between chart 2 and logMAR 0.4 text (r = 0.59, P < 0.01). Conclusion: The MNREAD Turkish version was tested using persons with normal vision and results were obtained from similar groups using daily reading material. The MNREAD acuity charts are logarithmic and continuous-text reading acuity charts for people in Turkey with normal and low vision. [ABSTRACT FROM AUTHOR]

In this article, the author discusses the need of designing the automated vision screening test for awarding driving license to overcome the issues such as visual acuity and colour blindness.

Background Rarebit testing implies probing for gaps in the neuro-retinal receptive field matrix, using bright microdots on a dark background. Previous reports have found rarebit testing useful for the detection of macular lesions. In its original implementation, the test requires darkroom facilities and a long test distance (2 m). Methods A self-contained rarebit test device was realised using a modified miniature data projector driven by a laptop computer. Its performance was assessed in normal subjects and in patients with advanced age-related macular degeneration. Results Normal subjects (N=49) produced test results very similar to those reported for the original rarebit fovea test. The patient group (N=12) performed significantly worse. The reproducibility was good, and the mean test time was 142 s. Conclusion The new test allows portable rarebit testing for neuro-macular damage, without the need for a darkroom. It may prove useful for screening for early age-related macular degeneration. [ABSTRACT FROM AUTHOR]