FACULTY OF OPTOMETRY (149

Background:Contrast sensitivity and depth perception are critical components of functional vision that extend beyond conventional visual acuity assessment. Myopia and hyperopia, as common refractive errors, are known to alter the optical quality of the retinal image, potentially affecting contrast detection and stereopsis. However, the degree and pattern of these alterations remain inconsistently reported in literature. Aim:This study aimed to compare contrast sensitivity and depth perception between myopic and hyperopic individuals with best-corrected visual acuity of 6/6, to determine the extent to which these refractive conditions influence visual performance. Methods: A cross-sectional analytical study was conducted among participants with diagnosed myopia and hyperopia attending the Optometry Clinic. Contrast sensitivity was assessed using the Pelli-Robson Contrast Sensitivity Chart, while depth perception was measured with the Lang stereotest under standardized illumination and testing distance. Refractive status was confirmed through objective and subjective refraction. Data were analyzed using appropriate statistical tests to compare mean contrast sensitivity and stereoacuity values between refractive groups, with significance set at p < 0.05. Results: The findings demonstrated a statistically significant reduction in mean contrast sensitivity among myopes compared to hyperopes (p < 0.05), indicating that myopia has a greater detrimental effect on contrast detection, particularly at lower spatial frequencies. In contrast, hyperopes exhibited relatively preserved contrast sensitivity but showed mild variability in binocular fusion responses. Regarding depth perception, myopic participants displayed poorer stereoacuity thresholds compared to hyperopic participants, suggesting that optical blur and aniseikonia secondary to myopic elongation may impair fine binocular disparity processing. No significant association was found between gender and either parameter, while age showed a mild negative correlation with both contrast sensitivity and stereopsis. Conclusion: The study concludes that myopia exerts a more pronounced impact on both contrast sensitivity and depth perception compared to hyperopia, even in the presence of full optical correction and normal visual acuity. These findings highlight the importance of including contrast sensitivity and stereopsis evaluation in routine refractive assessments to provide a more comprehensive understanding of visual function.

Tear film stability is vital for maintaining ocular surface health, visual clarity, and overall comfort. Variations in body composition, particularly Body Mass Index (BMI), have been associated with metabolic and inflammatory changes that may influence ocular physiology, including tear film quality and quantity. This study therefore investigated the relationship between BMI and tear film stability among students visiting the Optometry Clinic, University of Benin. A total of 120 participants aged 18 to 27 years (mean age 22.65 ± 2.24 years) were recruited. Data collected included age, gender, spectacle and contact lens use, BMI, Ocular Surface Disease Index (OSDI) score, Tear Meniscus Height (TMH), and Fluorescein Tear Break-Up Time (FTBUT). Descriptive statistics were used to summarise participant characteristics. Pearson’s correlation coefficient was employed to determine relationships between BMI and tear film parameters, while independent samples t-tests were used to compare mean tear film values across BMI and gender groups. The mean BMI was 24.57 ± 5.40 kg/m², the mean OSDI score was 24.68 ± 15.18, mean TMH was 0.22 ± 0.09 mm, and mean FTBUT was 11.97 ± 4.09 seconds. Statistical analysis revealed no significant correlation between BMI and any of the tear film parameters (p > 0.05). Similarly, gender-based comparison showed no significant differences in mean OSDI, TMH, or FTBUT values. In conclusion, this study found no significant influence of BMI on tear film stability among the student population. The findings suggest that within this young adult group, factors such as environmental exposure, digital device use, or lifestyle habits may exert a greater impact on tear film integrity than body mass index alone.