New rarebit vision test captures macular deficits hidden to acuity tests

• Published in: Acta ophthalmologica (Oxford, England) Vol. 93; no. 5; pp. 481 - 485
• Main Authors: Winther, Christina, Frisén, Lars
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.08.2015
• Subjects: age-related macular degeneration; AGE-RELATED MACULOPATHY; Aged; Aged, 80 and over; DEGENERATION; Female; Fluorescein Angiography; Geographic Atrophy - classification; Geographic Atrophy - diagnosis; Humans; macula; Macular Edema - diagnosis; macular oedema; Male; Middle Aged; Oftalmologi; Ophthalmology; PERIMETRY; rarebit; Reproducibility of Results; Retina - pathology; ROC Curve; Tomography, Optical Coherence; vision test; Vision Tests - methods; VISUAL-ACUITY; Wet Macular Degeneration - classification; Wet Macular Degeneration - diagnosis; macular oedema; visual acuity; rarebit; age-related macular degeneration; macula; vision test
• ISSN: 1755-375X; 1755-3768; 1755-3768
• DOI: 10.1111/aos.12659

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.