COMPARATIVE EFFECT OF CYLINDRICAL LENSES VERSES SPHERICAL EQUILIENT ON CONTRAST SENSITIVITY

Aysha Sharif, Asima Irshad, Aisha Arooj, Tahami Babar, Waheeba Awais, Amir Sultan

ABSTRACT

OBJECTIVE: To compare effect of cylindrical lenses verses spherical equivalent on contrast sensitivity.

METHODOLOGY: Randomized control trail sampling technique was used in this prospective study . Data was collected from Zubaida eyecare center Lahore during the period of February 2024 to March 2024. There were two groups from which one was given cylindrical correction and one was given spherical equivalent. Follow up was conducted monthly for 3 months to evaluate contrast sensitivity through Pelli Robson Chart. Data was collected through self-made performa. Data was entered and analyzed by SPSS-27 version. Friedman's Two-Way Analysis of Variance and Wilcoxon Signed Ranks test were applied to find the significance of data. P-value < 0.05 was considered as significant.

RESULTS: This study included 68 participants: 31 (45.6%) males and 37 (54.4%) females. The mean age was 23.462.48 SD (standard deviation), and the mean prescription was -3.95+ 1.12 SD. At first visit, the most frequently occurring value was 2.00, which appeared 41 times, making up 60.3% of the total occurrences. At the second visit, the most frequently occurring value was 2.00, which appeared 35 times, making up 51.5% of the total occurrences. Friedman’s test of significance was applied to find the significance of data and P-value was < 0.001 which was highly significant as significance border value was < 0.05. Wilcoxon signed rank test was pragmatic to find significance between two visits. There was highly negatively correlated as contrast sensitivity was negatively correlated with prescription power.

CONCLUSION: Data was highly significant and negatively correlated as higher prescription was associated with decreased contrast sensitivity and lower prescription was associated with higher contrast sensitivity. Cylindrical correction improved contrast sensitivity significantly as compared to spherical equivalent prescription. We should prescribe cylinder instead of spherical equivalent specially in moderate to high astigmatism as their visual acuity as well as contrast sensitivity increased.

RCT Registration # . NCT06407336

KEY WORDS: Contrast sensitivity, Spherical equivalent, cylindrical lenses, refractive error,