"Masked" pseudoexfoliation syndrome in unoperated eyes with circular posterior synechiae - Clinical-electron microscopic correlation

Objective: To investigate the prevalence of "masked" pseudoexfoliation (PEX ) syndrome in eyes with circular posterior synechiae receiving antiglaucoma tous therapy with miotics. Design: Cross-sectional prospective study. Methods: Twenty-eight eyes of 27 consecutive patients with circular posteri or synechiae and a history of miotic drug use without previous intraocular surgery, inflammation, or trauma, and without conventional signs of PEX mat erial in the anterior chamber were included in the study. All eyes were inv estigated by slitlamp biomicroscopy and gonioscopy of the anterior chamber before extracapsular cataract surgery for the presence of typical PEX-assoc iated iris pigment epithelial changes, such as peripupillary atrophy and tr abecular meshwork melanin granule deposition. The anterior chamber depth, l ens thickness, and axial lengths of the eyes were measured by A-scan immers ion sonography. The excised anterior lens capsules obtained during extracap sular cataract surgery were investigated for the presence of precapsular fi brillar PEX deposits by electron microscopy. Main Outcome Measure: The prevalence of masked PEX syndrome in eyes with ci rcular posterior synechiae receiving antiglaucomatous therapy with miotics. Results: Transmission electron microscopy of unselected nonserial sections revealed a precapsular layer consisting of typical PEX fibers or microfibri ls, which indicated early stages of PEX syndrome in 18 (64%) of 28 eyes wit h circular posterior synechiae. Melanin granules were frequently found adhe ring to the fibrillar layer. Eyes with precapsular fibrillar deposits showe d significantly greater trabecular meshwork pigmentation than eyes without such deposits. Differences in age, lens thickness, axial length of the eye, anterior chamber depth, and degree of peripupillary atrophy were, however, not statistically significant between the groups with and without electron microscopic evidence of PEX deposits. Conclusions: Circular posterior synechiae were more frequently associated w ith manifest or early stages of PEX syndrome. However, the formation of bro ad posterior synechiae in miosis prevented a definite clinical diagnosis ba sed on the classic changes of the anterior lens capsule. In eyes with spont aneous or miotic-induced circular posterior synechiae without other obvious cause, the masked variant of PEX syndrome should always be considered.