Clinical and Optical Coherence Tomography Features in Unilateral versus Bilateral Pseudoexfoliation Syndrome

PURPOSE: To compare clinical findings and peripapillary retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) in affected and fellow eyes of patients with unilateral pseudoexfoliation (PXF) syndrome with that of bilateral cases. METHODS: This cross-sectional study enrolled 91 subjects with PXF including 32 unilateral and 59 bilateral cases. Subjects with elevated intraocular pressure or findings suggestive of glaucoma were excluded. RNFL thickness and optic nerve head profile were studied in all eyes using the RNFL and optic nerve head analysis OCT protocol. Clinical and OCT features were compared in affected and unaffected eyes of unilateral PXF subjects to bilateral cases. RESULTS: Bilateral cases with PXF were older (P<0.01) and had thinner RNFL (P=0.04) than unilateral cases. From a total of 32 unilateral PXF cases, 7 subjects demonstrated RNFL thinning in the clinically normal fellow eye; all of these eyes had evidence of pupillary ruff atrophy on slit lamp examination in the absence of evident exfoliation material in the eye. Similar ruff atrophy with RNFL thinning was seen in 38 of 59 bilateral and in 16 of 32 unilateral cases. Pupillary ruff atrophy predicted RNFL thinning with sensitivity of 88.9% (95% CI, 73-96.7%) and 79.2% (95% CI, 74-84.5%) in bilateral and unilateral cases respectively, with low specificity of 45.8% (95% CI, 33.9-51.7%) and 45.5% (95% CI, 22.9-68.8%) in the same order. CONCLUSION: Patients with bilateral PXF have significantly thinner RNFL as compared to unilateral cases. Iris sphincter abnormality, clinically detected as pupillary ruff atrophy, may reflect early glaucomatous damage; however the specificity of this sign for predicting RNFL thinning is low.