Effect of age and gender on the vertical cup-to-disc ratio in a normotensive population

Abstract

Background: Evaluation of the optic disc is an important clinical practice among eyecare practitioners. Inter-observer variability makes it difficult to establish a clear conclusion regarding the estimation of the vertical cup-to-disc ratio (VCDR), especially in the context of glaucoma.

Aim: To determine the effect of age and gender on VCDR in a normotensive population and to estimate the mean VCDR of individuals of African descent.

Setting: The University Eye Clinic, Imo State University, Owerri, Nigeria.

Methods: A cross-sectional study was used to assess the VCDR morphology of participants. The mean age was 36.7 ± 12.98 years (range: 18 years – 60 years). Descriptive statistics were used to summarise the data characteristics while linear regression was used to determine the correlation of age, gender and VCDR. Data were analysed using Statistical Package for the Social Sciences (SPSS) version 21.

Results: From 102 participants selected for the study, 82 eyes were objectively examined in this study. The mean VCDR was 0.34 (95% confidence interval [CI]: 0.23–0.52, standard deviation [s.d.] = 0.09). Although the mean VCDR for men (0.35 ± 0.08) was slightly larger than that of women (0.33 ± 0.10), the difference was only 2%. Simple regression analysis showed a weak positive but significant correlation between age and VCDR (R = 0.24, R² = 0.057, p = 0.031), while the multiple regression revealed no interaction between age, gender and VCDR (all p > 0.05).

Conclusion: Our study did not provide statistically significant evidence to support a correlation between VCDR, age and gender. However, age and VCDR are weakly correlated (R = 0.24, p = 0.031), with a small increase in VCDR with age.

Contribution: This study sheds light on the correlation between demographic factors and the optic disc or nerve head, which could have implications for glaucoma diagnosis, especially concerning the African population.