Normative Values of Intraocular Pressure and Optic Disc Cup-to-Disc Ratio in Adults in Benghazi, Libya

Abstract

Intraocular pressure and the optic disc cup-to-disc (C/D) ratio are essential clinical parameters in the early detection of glaucomatous optic neuropathy. Variations in these measurements may occur due to age, gender, and individual anatomical differences, making population-based data important for clinical interpretation. This study aimed to evaluate intraocular pressure and optic disc cup-to-disc ratio among adult patients. A cross-sectional study was conducted in the Ophthalmology Outpatient Department of Benghazi Eye and Ophthalmic Surgery Teaching Hospital between January and March 2025. Adults aged 18 years and older attending for routine eye examinations or minor non-glaucomatous complaints were recruited. Intraocular pressure was measured in both eyes using Goldmann applanation tonometry between 9:00 and 11:00 AM. Optic disc C/D ratio was assessed by slit-lamp biomicroscopy with a fundus lens. A total of 139 participants were analyzed (mean age: 60.28 ± 9.08 years; 59.4% females). The mean IOP was 13.36 ± 2.80 mmHg in the right eye and 12.79 ± 2.62 mmHg in the left eye. The mean C/D ratio was 0.36 ± 0.19 in the right eye and 0.37 ± 0.19 in the left eye. IOP showed no statistically significant association with age or gender. However, males had significantly higher C/D ratios in both eyes compared to females (p < 0.05). Intraocular pressure values were within normal limits and were not significantly influenced by age or gender. Optic disc C/D ratios demonstrated significant gender-related differences, with higher values observed in males. Routine assessment of optic disc morphology is recommended, with consideration of gender-related differences.