Elevated Intraocular Pressure induces Ultrastructural Changes in the Trabecular Meshwork

Abstract

AbstractThe elevation of intraocular pressure (IOP) can be caused by the obstruction of flow in the trabecular meshwork and the age of the individuals has been pointed as one risk factor influencing in developing glaucoma. This study was designed to elucidate the morphological and ultrastructural changes in the trabecular meshwork of young adult Göttingen minipigs eyes after experimentally inducing a moderated chronic elevation of intraocular pressure lasting for over 14 months. The method used was cauterization of episcleral veins, located post-trabecular in the flow pathway and thus not affecting the cells located in the trabecular meshwork. The tissue was analysed using electron microscopy in control and experimental eyes. An increase in the amount of fibrillar material in the subendothelial region with a decreased optically empty spaces and an increase in rough endoplasmic reticulum (rER) were observed in the young experimental eyes. By experimentally increasing the post-trabecular resistance to the aqueous outflow, the present study showed that IOP elevation led to ultrastructural changes and thus concluded that changes in the trabecular meshwork can take place not only due to the advanced age, but by mechanical action on the cells as well.