Relevance of relationships between eye structure measurements for risk of anterior chamber angle closure

Aim of the study:To analyze the relationships between eyeball length, anterior chamber depth and lens thickness with respect to age and refractive state and in chronic versus acute angle-closure glaucoma.Material and methods: 240 patients were evaluated: 180 patients with different refractive states and 60 patients with primary angle-closure glaucoma, acute angle closure glaucoma and cataract.Results: We propose a predictive factor (PF) for anterior chamber angle closure based on ultrasound biometrics.PF = AC / AL / LT × 100.A significant decrease in PF with age was noted in all refractive states.In hypermetropia, PF was significantly lower than in myopia and emmetropia.PF is more sensitive than Lowe's coefficient towards a tendency for angle closure with respect to age and refractive state.A significant difference in PF was observed between acute angle closure and cataract groups, and between chronic angle-closure glaucoma and cataract groups.Its significance was higher than the significance of Lowe's coefficient between the respective groups.PF below 2.5 is a significant risk factor of anterior chamber angle closure.Conclusions: The risk of anterior chamber angle closure is primarily determined by relationships between measurements of eyeball structures (eyeball length, anterior chamber depth, lens thickness).We propose a PF coefficient calculated from these relationships, which reliably predicts the risk of anterior chamber angle closure.