Perspective Chapter: Role of the Vitreoretinal Interface Condition in the Development of Glaucoma

*Alexey Ermolaev*

## **Abstract**

Until now, there are no objective criteria to understand the moment of transition of eyes, anatomically predisposed to primary angle-closed glaucoma, from the risk group to the real form of PACG. IOP on the predisposed eyes may remain normal until advanced age without treatment. The aim of this study is to identify factors that can act as a trigger mechanism that starts such transition and the role of vitreous-retinal interface (VRI) condition in this process. A risk group that included 259 eyes (37– 88 years old) predisposed to PACG was formed. The criteria for forming the group were gonioscopy, predictive coefficients Lowe and Chirshikov, provocative Hyams test, and ultrasound examination. Monitoring was carried out for up to 4 years. In the risk group, there were eyes in which the state of predisposition was transformed into a real form of PACG during monitoring. Such a transition was accompanied by the occurrence of PVD, which was not detected at the beginning of the monitoring. In eyes with normal IOP predisposed to PACG, PVD appearance leads to destabilization of the vitreous body position inside the vitreous cavity, possibility for iris-lenticular diaphragm displacement forward, appearance of hydrodynamic blocks and undulating IOP increases, and appearance of the real form of PACG.

**Keywords:** primary angle-closed glaucoma (PACG), vitreous-retinal interface, posterior vitreous detachment (PVD), predisposition to PACG, Hyams test

#### **1. Introduction**

Due to the rapid development of vitreoretinal surgery, the vitreoretinal interface (VRI) is the subject of active discussions among ophthalmologists. However, the question of the VRI role in the hydrodynamics of the eye has been studied not enough. One of the subjects of our interest is the influence of VRI condition on the mechanisms of primary angle-closure glaucoma (PACG) development.

The fact is that the development of PACG can occur only in the eyes, in which there is an anatomical predisposition to this disease. This includes a narrow-angle of the anterior chamber of the eye (ACA), which is formed against the background of a disproportionate ratio of the short axial length of the eye and the excessive thickness of the lens. Usually, such eyes have hypermetropic refraction. The primary

manifestation of PACG and intraocular pressure (IOP) increases according to the "closed-angle" type occurs on the background of age-related changes. More often these will be undulating IOP increases but in some cases, acute attacks of PACG may develop.

Although in most cases a predisposition to PACG can be identified at an early age, physicians with extensive clinical experience know that IOP in such eyes can remain normal for an indefinitely long time. However, it is difficult to predict the moment when the primary manifestation of PACG in the predisposed eyes will occur.

In cases where we are dealing with eyes at-risk group of PACG to prevent diseases from developing, at some moment it is necessary to make a laser iridectomy. We need an objective criterion in order to decide when to do it, whether laser iridectomy needs to be done urgently, and when the patient can be left for monitoring at the risk group. We assume that the study of the VRI condition can help in solving this issue.
