Effect of topical Corticosteroids on the angle of anterior chamber in rabbit eyes

ABSTRACT

The steroid glaucoma is well-established clinically, however, the mechanism by which the corticosteroids can elevate the I.O.P. has not been fully determined. Thirty two rabbits, were chosen for this work and examined before drug application, then they were classified into two groups. The animals responded to steroid therapy in many ways as growth changes I.O.P. changes and histological as well as histochemical changes. Systemic side effects of the topical dexamethasone 0.1% eye drops were observed as weight loss and subsequent death in some animals. The contralateral [untreated control eyes] showed insignificant rise of I.O.P. and no changes in their histological or histochemical pictures. The rise of I.O.P. was obvious in steroid treated eye and was maintained by continuation of therapy. This rise of I.O.P. was associated with histological and histochemical changes in the angle as shown by different staining processes. The histological and histochemical changes were observed in the aqueous outflow passages mainly in the pectinate ligaments and trabecular region. Furthermore, these changes became more obvious by the increase in time of therapy. In the present work, accumulation of acidic mucopolysaccharides, deposition of fibrinois materilas and presence of active fibroblasts with increased cellularity were discerned. Some eyes showed weakened pectinate ligament fibres and destructed trabecular lamellae after steroid therapy. The conclusion of this study is that the steroid induced glaucoma was not due to a certain individual effect, but it was most probably attributed to multiple effects of steroids. More investigations and experimental studies are still needed to evaluate how much each factor can affect the ocular response to steroids in cortisone glaucoma