A retrospective study: Correlations between cup to disc ratio, age, gender, intra-ocular pressure, and disc asymmetry

Abstract

Four hundred and eighty-eight randomly selected patient records (250 males with a mean age of 38.40 years, and 238 females with a mean age of 36.51 years) were evaluated for possible correlations between gender, age, cup to disc (C/D) ratio, intra-ocular pressure, refractive condition, and C/D asymmetry (asymmetry is defined as the difference between the horizontal and vertical C/D ratios). Mean C/D ratios for males and females were 0.269 and 0.256 respectively, while a mean intra-ocular pressure for males was 14.6 mm Hg and for females was 14.3 mm Hg. This study revealed moderately significant (0.731 to 0.790) correlations between age and C/D ratio, while a slightly greater level of significance (0.832) was recognized between age and intra-ocular pressure. C/D ratios correlated at a fairly significant level (0.767 to 0.971) to refractive condition. While C/D asymmetry correlated poorly with refractive condition (0.265) in males, it correlated significantly (0.889 to 0.947) in females, with myopic females having the highest correlation (0.947). Approximately 79% of males and 81% of females in this study had C/D ratios less than 0.40. Correlations were more significant (0.745 to 0.868) for C/D ratios equal to or above 0.40. Vertical asymmetry, or vertical elongation of the C/D ratio of 0.10 or more was significantly correlated (0.948) to intra-ocular pressure. The results of this study suggests there exists significant correlations between age, gender, C/D ratio, intra-ocular pressure, and C/D asymmetry