Color discrimination in cataract patients under day and night conditions: assessment and correlation with lens opacity

Purpose: To investigate color discrimination performance and its relationship with lens opacity in cataract patients under daytime and nighttime conditions.

Methods: Color discrimination of seven hues (red, orange, yellow, green, cyan, blue, and purple) was assessed in 68 cataract patients using a dedicated software tool. Pairwise Spearman correlation analyses were conducted to examine relationships between color discrimination thresholds under daytime and nighttime conditions. Lens opacity was quantified and correlated with color resolution thresholds, defined as the minimal distinguishable wavelength difference within each color range.

Results: All 68 patients successfully completed the color vision assessment. In cataract patients, scores for red and green were the lowest (p < 0.05). Under daytime condition, orange and blue scores showed a negative correlation (r = –0.57, p < 0.05). At nighttime, purple and green (r = 0.59, p < 0.05), purple and blue (r = 0.52, p < 0.05), and blue and green (r = 0.46, p < 0.05) scores were positively correlated. Analysis of lens density and fine color discrimination revealed negative correlations between lens density and cyan and purple scores during daytime (p < 0.05), and between lens density and purple scores at nighttime (p < 0.05).

Conclusions: Cataract-related lens opacity impairs color discrimination. Due to protein aggregation, increased lens scattering, and alterations in the refractive index of the central region, cataractous lenses lead to declines in red and green visual function, alter inter-color relationship, and reduce resolution of short-wavelength light. These findings underscore the importance of comprehensive color vision assessment in cataract management and highlight potential targets for preserving visual function in aging populations.

Pan Xingchen is a PhD student in the Department of Ophthalmology at Peking University Third Hospital. Her research focuses on dynamic vision and color vision, with particular interest in how chromatic information is processed under varying luminance, motion, and environmental conditions. Her work emphasizes quantitative, function-based visual assessment, investigating how color discrimination and dynamic visual performance are modulated by optical changes and external stressors. By integrating psychophysical paradigms with objective ocular measurements, she seeks to elucidate the mechanisms underlying chromatic and motion-related visual function. Her work aims to clarify how color and motion information are functionally processed in the human visual system, and to develop more sensitive, clinically applicable approaches for assessing dynamic and chromatic vision.