Association Between Cataract and Visual Function in Elderly Patients at Rethabile Health Centre in Capricorn District, Limpopo Province, South Africa ^†

Background: Owing to aging, the human eye goes through changes, which include the loss of transparency of the crystalline lens, a clear structure inside the eye that is responsible for clarity of vision by focusing light rays onto the retina. This loss of transparency is known as cataract, which is known to cause scattering of light inside the eye, reducing the quality of the image formed on the retina. Different types of cataracts affect the visual system’s performance, known as visual function, which is related to quality of life. Visual function relates to vision-related daily life activities, which necessitates the study of the association of cataract with aspects of the visual system.

Objectives: The aim of this study was to assess the visual function of elderly patients, determine the most common cataract type, and analyse the association of cataract with visual function.

Methods: This study employed a cross-sectional, non-experimental quantitative approach. The study included 47 elderly patients presenting at the eye clinic at Rethabile Community Health Centre in the Capricorn district of Limpopo Province, South Africa. Visual function tests performed included visual acuity, colour vision, and contrast sensitivity. Cataract assessment was carried out with a slit lamp. The Shapiro–Wilk test was used to assess the normality of the data. A p-value of less than 0.05 was considered statistically significant.

Results: Of the 47 participants in this study, 26 had posterior subcapsular cataract, 12 had cortical cataract, and 9 had nuclear cataract. There was a low positive correlation (r = 0.3) between the type of cataract that a patient had and visual acuity, a negligible positive correlation (r = 0.03) with colour vision, and a low negative correlation (−0.2 < r < −0.4) with contrast sensitivity across all spatial frequencies. There was a strong positive correlation (r = 0.6) between the severity of cataract and visual acuity, a strong positive correlation (r = 0.7) with colour vision, a strong negative correlation (r = −0.7) with contrast sensitivity at low and moderate spatial frequencies, and a moderate negative correlation (r = −0.5) with contrast sensitivity at high spatial frequencies.

Conclusions: An increase in cataract severity is closely associated with a decline in visual acuity, colour perception, and contrast sensitivity at low and moderate spatial frequencies.