H Nakamura¹, K Oda¹, M Yuzawa²
¹Tokyo Womans Christian University, Communication, Tokyo, Japan; ²Nihon University, Ophthalmology, Tokyo, Japan
Purpose: As we reported previously (ARVO 2000), reading charts presented on a large plasma display (Plasma MNREAD-J) could extend the range of character size and enabled us to find appropriate magnifying power for patients with AMD. Here we report how we actually prescribe reading aids.
Method: Subjects were 18 low vision patients with scar-stage AMD in their both eyes (aged 78±5) for whom we could not obtain reasonable maximum reading rate with paper charts. A computer-controlled presentation of reading sentences on 42 inch plasma display (Fujitsu PDS4203J) was used to test character sizes from 1.35 logMAR to 2.15 logMAR (4 to 26 degrees). Critical print size (CPS) was used to determine magnification power for reading aids. We compared reading speeds with CCTVs of 14 inch and 34 inch display.
Result and Discussion: From CPS evaluation, appropriate magnification power of the aids for newspaper ranged from 10.0 to 44.7. Seventeen out of 18 patients were prescribed the reading aids; 13 patients CCTVs and 4 patients optical magnifiers for some reasons. The CCTV with 14 inch display, which is common in Japan, was appropriate for only 2 patients. The rest could not achieve their maximum reading with the small display, but did with 34 inch CCTVs. The difference between these two groups was the necessary magnification power; the former needed 10 time magnification, while the latter needed more than 18 times. With 14 inch CCTV, only a few characters were presented on the monitor for 18 time magnified texts.
Conclusions: Patients with AMD could benefit from the appropriate prescription which was only possible with plasma MNREAD-J. The size of display would play a very important role for their prescription, for even CCTV limits the field of view when larger magnification is necessary.
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