Posters

Pathogenesis and intraocular pressure increase after refractive surgery

Poster Details

First Author: S.Amansahatov 0

Co Author(s):    L. Shetinina   H. Durdymammedov                 

Abstract Details

Purpose:

It is known that cornea has both way permeability, from outside as well as from anterior chamber side. Moreover during PRK after removal of anterior epithelia we have observed that small droplets of liquid emerge on the surface of bowman membrane. This phenomena demonstrates that intraocular fluid flow through cornea is possible. The purpose of this study is to identify the role of cornea in the outflow of the intraocular fluid as well as regulation of IOP.

Setting:

Clinical experimental research was conducted in the Department of Refractive Surgery, Department of Experimental Research and the Department of Pathomorphology of the International Center of Eye Diseases in the city of Ashgabat.

Methods:

Clinical research was conducted on 5390 patients during 36 months period. 3190 patients have had PRK, 1825 had Lasik and 375 had Femtolasik. IOP was measured before surgery and on 7th, 14th and 30th days after the surgery. Experimental research was conducted on four rabbits (8 eyes), the depth of cornea’s oblation in rabbits was in the range of 80-120 microns. Histological slices thickness was 3-4 microns, were colored by hemotoxilin –eozin by Van Gison method and also by PAS reaction. Morphometry was conducted at x800 zoom level with the use of Image-Pro(R) Plus System.

Results:

Increase in IOP after laser surgery was observed in 15.4% of patients. After PRK in 11.4%, after lasik and femtolasik 4.06%. Morphological investigation on corneal discs have shown changes in the thickness of corneal stromal plates with reduction of interplate intervals in anterior 1/3 of stroma. Signficant increase in height and width of intraplate intervals is observed in posterior 2/3 of the stroma. Above mentioned processes lead to increase of density of collagen plates with reduction of longitudinal and transversal intraplate intervals. Resulting in possible a blockage of transportation of intraocular fluid through cornea.

Conclusions:

Research has shown that in between blinking tear film becomes hyperosmotic . Uncontested is the most significant role endothelia in support of hydration is osmotic pressure in cornea stromal. It is known that cornea has the ability of both way permeability. Therefore we hypothesize that cornea participates in regulation of IOP along with trabecular meshwork and uveoscleral drainage systems. Our experimental research have confirmed that after PRK treatment sharp increase in density of collogenal fibres is noted, which in turn prevents cornea to take part in regulation of IOP leading to increase of IOP in some patients.

Financial Disclosure:

NONE