Abstract
Purpose :
True changes in central visual function that are small in magnitude but subjectively appreciated may not necessarily be documented as being statistically significant due to potential measurement-related issues with existing chart-based tests of visual acuity (VA ) and contrast sensitivity (CS). We determined optical intervention-related changes in VA and CS for existing tests compared to two novel tests.
Methods :
The ETDRS trans-illuminated VA chart, Pelli-Robson CS, and active learning adaptive tests of VA (i.e., quantitative VA) and CS function (i.e., quantitative CSF) were repeated at two visits in 50 eyes of 25 normally-sighted, pre-presbyopic adults without ocular disease. Subjects were randomized and masked to perform these tests at 3-4m while wearing daily disposable Acuvue or Alcon contact lenses with distance-only and multifocal correction.
Results :
All except two subjects (92%) were accurately able to identify which contact lens was the multifocal, based on subjective visual disturbances. The qVA test measured a significantly greater VA loss with the multifocal on average when compared to the ETDRS chart (0.18±0.10 vs . 0.14±0.12 log units; p=0.03). The qCSF test measured a slightly greater CS loss at 3cpd with the multifocal on average when compared to the Pelli-Robson chart (-0.13±0.15 vs. -0.09±0.11 log units; p=0.12). Hypothesis testing for detecting VA loss of >7.5 letters with the multifocal with the qVA test was marginally significant (p=0.028; one-sided), but not significant for the ETDRS chart (p>0.50). For detecting CS degradations of >0.20 logCS with the multifocal lens, the measured changes were significant at 3, 6, and 12 cpd with the qCSF (p<0.025; one-sided), but not significant for Pelli-Robson (p>0.50).
Conclusions :
The definition of clinically meaningful changes in vision is constrained by what is clinically measurable, thus it is important to build better tools to detect subtle changes in visual function that are noted by patients. Our findings support that enhanced test design can reveal significant visual changes that have perceptual correlates.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.