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H. Roche, G. S. Rubin; Reading Performance in Patients With Type 2 Macular Telangiectasia. Invest. Ophthalmol. Vis. Sci. 2010;51(13):6004.
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Patients with type 2 macular telangiectasia (MacTel) frequently report greater difficulty on reading tasks than would be expected based on their visual acuity. It has been suggested that this difficulty is due to the position of their associated scotomas. Specifically, bi-temporal scotomas are thought to be common in MacTel and these result in a central binocular visual field defect that may be especially detrimental to reading. We set out to measure reading performance and see if this was correlated with scotoma location.
As part of the MacTel Project, twenty four patients with MacTel underwent reading evaluation using the International Reading Speed Test (IReST) for paragraphs (large text: 18 pt and small: 9 pt) and the Minnesota Reading Test (MNRead) test for sentences (variable print size). Reading speeds were calculated as the number of words read correctly per minute (wpm). Microperimetry was performed using the Nidek MP-1. Scotomas were classified as either having a bilateral temporal component or not.
Twenty four patients participated in the study with acuities in the better eye ranging from -0.04 (6/5) to 0.38 logMAR (6/14). Nine patients had temporal scotomas in both eyes. Reading speeds on the IReST were slower for patients with bi-temporal scotomas (134wpm ± 15wpm for large text and 96wpm ± 16wpm for small text), compared to those with other scotomas (mean =143wpm ± 11wpm and 108wpm ± 13wpm respectively), but the difference was not statistically significant (p > 0.6 for both text sizes). MNRead reading speeds were faster for the bi-temporal group (158wpm ± 12wpm) compared to the group with scotomas in other locations (139wpm ± 10wpm). Again this difference was not statistically significant (p=0.3).
Contrary to previous reports fewer than half the patients in our sample had bi-temporal scotomas. Furthermore, the presence of bi-temporal scotomas had no greater effect on reading speed than other types of scotomas in MacTel patients.
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