The relative lens position has been considered to be an important determinant in primary angle-closure glaucoma, but its predictive value needs to be assessed. Therefore, in this tertiary-care center-based case-control study, 70 cases and an equal number of controls were investigated to analyze this association. It was found that, after controlling for age, sex, and refractive error, the relative lens position and anterior chamber depth had a strong association with the disease in separate logit models (P < .01). The predictability of the separate logit models with the relative lens position and anterior chamber depth was found to be statistically significant (-2 x maximized logarithmic likelihood, 93.94 and 19.39, respectively, P < .01). Because the relative lens position represents a composite measure from a set of variables, it can be used as a significant predictive alternative to anterior chamber depth in the genesis of this disease.