https://doi.org/10.30702/Ophthalmology30062021-13.2.24-32/073.48
UDC 617.7-007.681:617.741-004.1]-073.48

Novytskyy I. Ia., Lopadchak R. M.

Department of Ophthalmology, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine

Abstract

The aim. To develop a predictive factor (PF) of anterior chamber (AC) angle closure based on biometric data and to compare its values with the Lowe coefficient and lens thickness to axial length factor (LAF) in healthy patients of different age, cataract patients and patients with chronic and acute angle-closure glaucoma.

Materials and methods. The study was performed in 180 variously-aged (20 to 60 years) patients with different types of refraction, and in 20 patients with acute AC angle closure, in 20 patients with primary chronic angle-closure glaucoma and in 20 patients with cataract. The AC depth, the lens thickness (LT) and the axial length (AL) were measured by A-scan ultrasound biomicroscopy.

Results. Based on ultrasound biometrics, a PF of anterior angle closure has been developed: PF = AC / AL / LT x 100. There was significant age-related decrease in the PF coefficient in patients with all types of refraction (p<0.001). In case of hypermetropia, PF was significantly less than in cases with myopia and emmetropia (p<0.001). Compared to the Lowe coefficient, the PF coefficient more sensitively showed the trend towards the closure of the AC angle in the age-refraction context.

The AC depth in case of an acute glaucoma (2.3 ± 0.16 mm) was significantly less than that in case of chronic angle-closure glaucoma (2.4±0.21 mm) and differed significantly from that in case of cataract (3.32±0.33 mm), in all groups p < 0.001. At the same time, LT did not differ significantly in patients with acute glaucoma, chronic angle-closure glaucoma and cataracts (p>0.05).

There was significant difference in PF coefficient between the groups of patients with an acute angle-closure glaucoma and cataracts, as well as chronic angle-closure glaucoma and cataracts (p<0.001). Its significance was higher than the significance of the Lowe coefficient between the respective groups. PF less than 2.5 was a significant risk factor for the closure of the AC angle.

Keywords: angle-closure glaucoma, anterior chamber depth, lens thickness, axial length, ultrasound biometrics, predictive factor, Lowe coefficient.