Роль возникновения задней отслойки стекловидного тела в патогенезе первичной закрытоугольной глаукомы

PURPOSE: Study of changes in the posterior part of eyes predisposed to primary angle-closure glaucoma (PACG) that contribute to patient's conversion from risk group to the disease. METHODS: 135 patients (223 eyes) anatomically predisposed to PACG development (37-88 years old, 87 females, 48 males) were studied and monitored for 4 years. PACG diagnosis had not been verified previous to the study. 176 eyes were pair eyes of 88 patients; in other 47 cases only one eye of the patient was studied because PACG had already been diagnosed in the second eye. Apart from standard ophthalmological study all patients underwent s-scan ocular ultrasound and prone-position provocative test for angle-closure glaucoma (Hyams test), during which the patients lay in prone position for 1 hour and IOP was measured before and right after the test. RESULTS: The eyes were divided into 2 groups depending on the Hyams test results: the 1-st group included patients with positive test results (IOP increase >5 mmHg) and the 2-nd group (risk group) - patients with negative test results (IOP increase <5 mmHg). Positive result of the prone-position provocative test was considered to be the main factor for PACG diagnosis verification in predisposed eyes. Patients with negative Hyams test results remained in the risk group without PACG diagnosis verification. Patients from the risk group were monitored without any treatment and re-examined every 6 months. In 31 patients Hyams test results were different in pair eyes: positive in one eye (1-st group) and negative in the other one (2-nd group). It is important to mention that Hyams test positive results were found in eyes predisposed to PACG only in cases of posterior vitreous detachment (PVD) - 67.7% of cases. In all cases with no PVD Hyams test was negative even if the patient had a narrow anterior chamber angle. The change of the prone-position provocative test results from negative to positive during follow-up (the transfer of predisposed eyes from risk group to the PACG) was found in 27 eyes. It happened in cases when PVD occurred during the monitoring process. CONCLUSION: A connection between PVD and change in eyes predisposed to PACG from risk group into real illness was found. We suppose that PVD disturbs the vitreoretinal adhesion and destabilizes the vitreous body position in the vitreous cavity. It can lead to vitreous body microexcursions in the direction of anterior chamber and lens-iris diaphragm displacement. This set of changes may provoke a hydrodynamic block development and lead to IOP increase.