Contrast-generated illusory motion can be used to evaluate contrast sensitivity changes in patients with retinal vein occlusions

Abstract

Purpose : Patients with retinal diseases commonly have vision changes that cannot be quantified by acuity measurements and imaging data. This study asserts that a more robust understanding of vision changes in retinal diseases can be achieved by analyzing contrast sensitivity (CS). A new tool known as the motion diamond stimulus (MDS) utilizes contrast-generated illusory motion in dynamic test regions to determine contrast sensitivity thresholds. The MDS and the Pelli-Robson were used to quantify vision changes in patients with retinal vein occlusions (RVO). We hypothesize that the MDS, compared to the Pelli-Robson, will reliably measure CS changes, while also quantifying additional aspects of contrast sensitivity.

Methods : In this prospective IRB-approved study, 20 patients with RVO in only 1 eye, who were receiving anti-VEGF treatment and had vision better than 20/40 were recruited. All subjects underwent 3 assessments: the Pelli-Robson, the MDS, and the NEI's VFQ-25. The MDS assessment produced 2 primary data endpoints, α and β, from multiple CS thresholds. The α value represents the overall contrast threshold level and the β value serves as a parameter to quantify the adaptability of the visual contrast system. The CS output parameters from the MDS and log CS Pelli-Robson values were used to compare RVO eyes (n=20) to control eyes (n=20).

Results : The study participants had a mean composite QOL score of 89.5±10.4 on the VFQ-25. A significant difference was observed between the RVO eyes and the control eyes in the Pelli-Robson log CS scores (p-value=0.0001). The MDS also exhibited a significant difference in α value between RVO and control eyes (p-value=0.01). No difference in β value was found between the study groups (p-value=0.39).

Conclusions : The results for the MDS assessment's α parameter corroborated the Pelli-Robson scores, suggesting contrast sensitivity threshold impairment in patients with RVO. No significant difference in β value was observed between study groups, suggesting that adaptability of the visual system is maintained in treated RVO. This may be due to effective anti-VEGF therapy and is supported by high VFQ-25 scores in these patients, but these findings require further study. This study also showed that MDS produces contrast threshold data comparable to the Pelli-Robson, while also providing additional quantitative data regarding CS adaptability.

This is a 2020 ARVO Annual Meeting abstract.