Clinicians and researchers often rely only on high-contrast visual acuity measures to assess contact lens performance and patient success. However, a recent study from the Brien Holden Vision Institute revealed that subjective vision ratings should be the primary performance measure and visual acuities as secondary—at least for multifocal lenses. The study also found that overall vision satisfaction ratings were the strongest indicator for willingness to purchase multifocal contact lenses. In the clinical setting, the most vital tests to gauge subjective visual performance would be high-contrast testing at 40cm and 50cm, as they showed a better correlation with subjective vision ratings.
Researchers performed a retrospective analysis of final visits of two masked, crossover clinical trials of nine prototype and four commercially available multifocal contact lenses in 141 presbyopes. They found that subjective vision ratings were significantly but weakly correlated with visual acuities. Still, subjective vision ratings were a better indicator of contact lens performance than visual acuities.
Understanding the patient’s visual satisfaction and daytime vision stability were major factors in determining the success of lens wear and, ultimately, willingness to purchase. For every one-unit increase in vision satisfaction rating (on a scale of four to nine), willingness to purchase increased by 20%.
The investigators also note that visual acuity measurements under well-illuminated conditions at distance and near may not reflect real-life conditions. While practitioners often report in-office vision as having excellent high-contrast visual acuity, a patient may still report poor vision in their own environment or during daily activities.
Researchers concluded that a standardized survey to ascertain contact lens performance would help practitioners and researchers improve patient care and research. Standardized guidelines on the assessment of vision with multifocal contact lenses would also help improve patient visual outcomes.
|Jong M, Tilla D, Sha J, et al. The relationship between visual acuity, subjective vision and willingness to purchase simultaneous-image contact lenses. Optom Vis Sci. March 21, 2019. [Epub ahead of print].|