Morphological and clinical studies on the exfoliation syndrome and open angle glaucoma

• Main Author: Konstas, Anastasios Georgios P
• Format: Dissertation
• Language: English
• Published: University of Glasgow 1992

Exfoliation syndrome may be defined as a condition in which there is a characteristic clinical pattern of deposition of fine white granular material upon and within ocular and orbital tissues. Morphologically, exfoliation material comprises randomly orientated fibrillar aggregates with the staining and ultrastructural characteristics of a protein. The origin and structure of this protein (exfoliation material) are uncertain. Exfoliation syndrome is a common, but poorly understood cause of glaucoma worldwide. Iris tissue samples from 100 patients operated upon for open angle glaucoma and 31 control subjects with closed angle glaucoma have been subjected to light and electron microscopy. This aimed at establishing a definitive diagnosis for the clinical study described below. Ostensibly normal iris vessels were found close to other vessels with intense perivascular aggregation of exfoliation material. Foci of exfoliation material in the iris stroma exhibited a pattern consistent with 'ghost vessels'. A diffuse distribution would have been anticipated if passive deposition of exfoliation material had taken place. Collagen types I-V and laminin were sought in 16 normal and 20 exfoliative specimens of iris and/or trabecular meshwork, by means of ultrastructural immunogold localisation. Collagen types I-V were not present in the exfoliation material. In this study the glycoprotein laminin has been identified, for the first time, as an integral component of the exfoliation material. The vascular matrices of exfoliative iris exhibited increased amounts of collagen types I and IV in less affected vessels. Depletion of collagen types I, IV and laminin was noted in severely affected vessels. In part II of this thesis the results of two prospective studies are presented. The first investigated the prevalence and clinical characteristics of exfoliation glaucoma. Surgical patients with open angle glaucoma were divided by clinical examination into 3 groups: definite exfoliation (22) ; possible exfoliation (18) and no exfoliation (60). Subsequent morphological assessment delineated two definitive groups: exfoliation glaucoma (26) and primary open angle glaucoma (74). Exfoliation glaucoma patients more frequently had higher untreated 10P at diagnosis, shorter duration of medical therapy, higher treated 10P before surgery and were operated upon more often for high 10P. They also exhibited significantly lower 10P postoperatively compared with age- matched primary open angle glaucoma patients. The second study was performed upon 78 patients and studied the effect of varying the position of a surgical fistula upon the incidence of postoperative hyphaema. This study confirmed that by fashioning the fistula entirely in corneal tissue the incidence and severity of postoperative bleeding is reduced resulting in shorter hospital stay. The incidence of postoperative hyphaema was lower in the exfoliation glaucoma group, but not significantly so. Neither the type of dissection, nor the occurence of hyphaema influenced the 10P at 4 months following surgery.