Rarebit testing is used to measure low degrees of neuro-visual damage and is available for free on the internet. It consists of a fixed bright light dot presented on a black background. During testing it is presented briefly at different locations centrally and peripherally. The size was fixed at 40×50 min of arc and the positions were varied at random within a 4.6×3.5-degree test field. The test task was to find the smallest rarebit number required to recognise the test digits. Thirty-seven patients with various stages of AMD and 25 control subjects participated in the evaluation, with an average age of 77 years. The results were compared with visual acuity measured using the Early treatment diabetic retinopathy study (ETDRS). Conventional acuity tests are not always sensitive in assessing macular functions in patients with AMD. The rarebit test appeared well suited for fine grading of vision in AMD. The authors conclude that this simple test is well suited for AMD patients. The simple set-up and lack of fixation demands made for practicable examinations of short durations.

New rarebit vision test captures macular deficits hidden to acuity tests.
Winther C, Frisén L.
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Nana Theodorou

BMedSCi (Hons) PhD, Sheffield Teaching Hospitals NHS Foundation Trust, Clinical Research Office, 11 Broomfield Road, Sheffield, S10 2SE, UK.

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