Abstract
Purpose:
The purpose of our study is to measure the reliability of two new tests that measure the contrast sensitivity (CS); the M&S smart system II single letter contrast test and the iPad letter test. These results were compared with those obtained from the Pelli-Robson (PR) test which is well-established and clinically accepted but no longer in production. In addition we also asked subjects if amber/yellow lenses improve their subjective perception of text and then determined if those subjects who experienced a subjective improvement in contrast had the greatest reduction in contrast initially.<br />
Methods:
24 low vision patients diagnosed with either myopic degeneration or advanced glaucoma were selected from the Illinois Eye Institute. Inclusion criteria included 20/70 VA or worse in the better seeing eye or a visual field of 20 degrees or less in the better seeing eye. Patients were examined at two separate visits 1 month apart (+/- 1 week). During each visit, patient CS was measured using three different tests: iPad version of PR, M&S contrast sensitivity and PR.<br />
Results:
Results: Reliability was assessed with the intraclass correlation coefficient (ICC). Results indicate that the CS obtained on the first visit was very similar to that obtained from the second visit. The ICC values for the 3 tests are: PR=0.82, MS=0.91 and IPAD=0.93 (p=0.001). However, an analysis of variance (ANOVA) reveals that the absolute CS values differ between the tests; the PR and IPAD CS values differ significantly (F=4.06, p=0.026).<br /> We also found that low vision patients subjectively prefer to have their specs tinted; we did not find a preference for yellow or amber tint but in general any sort of tint was preferred.
Conclusions:
Two new CS tests; the M&S smart system II single letter contrast test and the iPad letter test, were compared with the well-established PR test in a low vision sample population. Our results indicate that the CS obtained on the first visit was very similar to that obtained from the second visit. The absolute CS values differ between the tests; with a significant difference between the PR and IPAD CS. We also found that low vision patients subjectively prefer to use yellow or amber tinted specs.<br />