Low Selenium Associated with PEX Syndrome

MERSIN, TurkeyReduced levels of selenium in the aqueous humor may impact antioxidant defenses in the eye and may be related to onset of pseudoexfoliation (PEX) syndrome, according to a new study (Am J Ophthalmol. ePub 2010 Dec 17. DOI: 10.1016/j.ajo.2010.08.032). PEX syndrome occurs when a flaky material peels off the outer layer of the eyes lens; the material collects in the angle between the cornea and iris, clogging the drainage system of the eye. This can cause a build-up of intraocular pressure and PEX glaucoma, the most common form of secondary open-angle glaucoma worldwide.

Researchers from Mersin University Faculty of Medicine, Turkey, sought to examine the levels of selenium in aqueous humor, conjunctival specimens and serum of subjects with and without PEX syndrome, and to determine the role of selenium in the development and pathogenesis of PEX syndrome. During cataract surgeries on 27 cataract patients with PEX syndrome and 20 age-matched cataract patients without PEX syndrome, researchers collected aqueous humor, conjunctival specimens and serum, and measured selenium levels of the samples.

Patients with PEX syndrome had significantly lower mean selenium levels in aqueous humor and conjunctival specimens, compared to the control group. Mean selenium levels in serum of patients with PEX syndrome were also lower than control subjects, but the difference was not statistically significant. The researchers suggested reduced levels of selenium in patients with PEX syndrome indicate a possible role of impaired antioxidant defenses in the eye, which could be associated with the pathogenesis of PEX syndrome.