Could VA predict the visual preference between 2 different PALs?

Abstract

Purpose : We aimed to determine if Visual Acuity (VA) can be a good predictor of quality of vision when wearing a Progressive Addition Lens (PAL).

Methods : 20 presbyopic subjects (48 to 62 years old; VA better than 0.0 logMAR) viewed monocularly through PALs with their subjective refraction and an addition 2.0D, allowing to see clearly a newspaper displayed on a monitor at 50 cm (visual fields of around 50° corresponding to ± 14 mm eccentricity on the lens) and have to indicate which of the PAL gives the overall best quality of vision. We also measured C-Landolt VA using FrACT at various eccentricities (from -12 nasal to +12 temporal each 3mm) measured along a horizontal line passing through the near optical center. 2 types of PALs were tested, with clearly differentiated astigmatism distribution.

Results : 15 subjects preferred the quality of vision with PAL1 and 5 subjects preferred PAL2. For 40% of them the difference was strong, for 30% it was moderate and for the remaining 30% the difference was low. VA was statistically different (Wilcoxon test) between the 2 PALs at 0, -9, -12, +12 mm of eccentricity. Mean VA in the center (-6 to +6mm) obtained with PAL2 was statistically better (p<0.01) whereas in the periphery (-9 to -12 and +9 to +12mm), PAL1 gave statistically better VA (p<0.01). Whatever the eccentricity, the difference between both PALs was never higher than 0.1 logMAR. The level of preference (low, moderate, high) was analyzed against the difference of VA between both PALs considering either the center or the periphery. The difference of VA did not permit to predict the preferred PAL. For only two third of the subjects, VA obtained in the periphery could gave a clear indication of which PAL was preferred.

Conclusions : Visual acuity seems not able to predict quality of vision through PALs.

This is a 2020 ARVO Annual Meeting abstract.

 

Figure 1: A - Mean VA (logMAR) measured with PAL1 (purple line) and PAL2 (yellow line) according to eccentricities (-12 to 12 mm). Vertical bars represent standard error and black stars denote significant differences (Wilcoxon test, *p < 0.05). B - Level of preference plotted against VA difference between both PAL considering the center (diamond) or the periphery (triangle). Each diamond or triangle represents one subject. Red circles represent subjects for who VA could not predict the subjective quality with a PAL.