Generalized transluminance of the iris and the frequency of the pseudoexfoliation syndrome in the eyes of transient ischemic attack patients.

Background: Abnormal generalized iris transluminance has been reported to have connection with the pseudoexfoliation syndrome (PXS). According to angiographic studies, microvascular changes are found to be present on the iris of these patients, which suggests that hypoxia has a role in the development of PXS. On the other hand, carotid transient ischemic attack (TIA) patients have been shown to have some ocular key symptoms due to hypoxia.

Methods: Iris photographs of 62 unselected TIA patients (124 eyes) and 32 healthy subjects (64 eyes) were evaluated in a blind trial to show the presence of iris transluminance of these eyes. Biomicroscopic examination was performed to show the presence of the PXS.

Results: Abnormal iris transluminance was positive in 42% of the right eyes and in 45% of the left eyes in patients in the study group. The corresponding figures for the control group were 16% in both eyes (P = 0.01, chi-square test). When the study group was divided into subgroups according to stenosis of carotid bifurcation, the figures were highest in those cases where one or both carotid arteries were stenosed over 50%. Pseudoexfoliation syndrome was found in 18% of the right eyes and in 23% of the left eyes of TIA patients. The frequency of PXS in these eyes was approximately two times higher than reported in earlier studies of the frequency of PXS in healthy subjects of the same age in a Finnish population.

Conclusion: Abnormal iris transluminance is one of the ocular key symptoms of extracranial cerebrovascular disease. Coexistence of cerebrovascular disease with abnormal iris transluminance, together with increased prevalence of pseudoexfoliation supports the theory that hypoperfusion is a contributory factor in the development of PXS.