This study reports that subjective vision ratings are better indicators of willingness to purchase simultaneous-image contact lenses than visual acuities and are more valuable in evaluating contact lens performance.
The purpose of this study was to investigate the relationship between visual acuities, subjective vision ratings, and willingness to purchase simultaneous-image contact lenses in presbyopes.
A retrospective analysis of visual acuities, subjective vision ratings, and willingness to purchase from final visits of two masked, crossover clinical trials of nine prototype and four commercially available simultaneous-image contact lenses in 141 presbyopes was performed. Pearson correlation and area under the receiver operating characteristic curve determined correlations between variables.
Most subjective vision ratings were weakly correlated (r < 0.3) with visual acuity at all distances and illumination. Moderate correlations (r, 95% confidence intervals) were found between overall vision satisfaction ratings with visual acuity at 40 (−0.34, −0.28 to −0.40) and 50 cm (−0.33, −0.27 to −0.39), near-vision ratings (daytime) with visual acuity at 40 (−0.48, −0.43 to −0.53) and 50 cm (−0.46; −0.41 to −0.51), and intermediate-vision ratings (daytime) with visual acuity at 40 (−0.39, −0.33 to −0.45) and 50 cm (−0.41, −0.35 to −0.46). Highest discrimination for willingness to purchase was with overall vision satisfaction (area under curve, 0.93) and vision stability (daytime; area under curve, 0.77). Ratings from 4 to 9 for vision satisfaction showed a linear increase in willingness to purchase: a 1-unit increase in vision satisfaction increased willingness to purchase by 20%. Ratings lower than 4 had 0% willingness to purchase. Other subjective ratings showed similar relationships, albeit only 10 to 15% increase in willingness to purchase per unit increase for ratings higher than 4.
Subjective vision ratings are a better indicator of simultaneous-image contact lens performance than visual acuity. Overall vision satisfaction and vision stability are key predictors of willingness to purchase. Subjective vision ratings should be used to evaluate performance rather than visual acuity alone.