A Comparative Study of Contrast Sensitivity among Hyperopic and Myopic Patients Visiting the Optometry Clinic in Aminu Kano Teaching Hospital Kano, Nigeria

Abstract

Contrast sensitivity is an important component of visual function that affects real-world tasks such as driving, reading, and facial recognition, especially under low-light conditions. This study was a cross-sectional, hospital-based study to compare the contrast sensitivity performance between hyperopic and myopic adult participants attending the Optometry Clinic at Aminu Kano Teaching Hospital (AKTH), Kano, Nigeria. A total of 130 adult participants aged 18–50 years were recruited through simple random sampling. Participants had their refractive error assessment with an auto-refractor. Contrast sensitivity was measured using the Pelli-Robson chart. Data were analyzed using SPSS version 25. Independent t-tests, ANOVA, and Pearson correlation were used to compare contrast sensitivity between groups and determine the effect of age and refractive error severity. Hyperopic patients had slightly higher contrast sensitivity scores across monocular and binocular assessments, but the differences were not statistically significant (p > 0.05). Specifically, binocular contrast sensitivity was 1.65 ± 0.09 in hyperopic patients and 1.60 ± 0.09 in myopic patients. In myopes, contrast sensitivity improved with decreasing myopia (e.g., r = 0.755 for RE OD vs CS OU, p < 0.001). In hyperopes, contrast sensitivity declined with increasing hyperopia (e.g., r = -0.713 for RE OS vs CS OU, p < 0.001). This study revealed slightly higher contrast sensitivity in hyperopic patients, a non-significant decline with age, a strong correlation between refractive error severity and contrast sensitivity.  These findings emphasize the importance of including contrast sensitivity testing in routine eye examinations to enhance clinical decision-making and patient care.