New York-A patient with exfoliation syndrome (XFS) may have the worst type of open-angle glaucoma, according to Robert Ritch, MD, who opened a session on XFS at the Glaucoma 2006 meeting.
A patient with glaucoma and XFS has higher IOP, worse optic disc and field damage, and a greater failure rate with medical therapy than individuals with primary open-angle glaucoma, said Dr. Ritch, surgeon director and chief of glaucoma services at The New York Eye and Ear Infirmary, New York, professor of clinical ophthalmology at New York Medical College, Valhalla, and one of the chairmen of the meeting.
Studies have shown that the risk of development of glaucoma in those with ocular hypertension and the risk of progression of glaucomatous damage for patients with XFS with glaucoma is double that of those without the condition, Dr. Ritch said.
Predisposing factors for angle-closure associated with XFS include zonular weakness (a thicker lens and anterior lens movement), rigidity of the iris, a sluggish pupil, and posterior synechiae. Cataract is also associated with the syndrome. Unilateral cataract and XFS are almost invariably in the same eye, with ischemia or oxidative damage possible causes.
When it comes to cataract surgery, the complication rate for such patients is 7 to 10 times greater with extracapsular cataract extraction, less with phacoemulsification. Predisposing factors such as posterior synechiae, zonular weakness, fragility of the capsule, phacodonesis, and poor pupillary dilation lead to complications that include zonular dehiscence, capsular rupture, and loss of vitreous.
XFS appears to be associated etiologically with retinal vein occlusion. In addition, XFS is a systemic disease, Dr. Ritch emphasized. Exfoliation-like fibrils can be found in many organs-the heart, lung, meninges, kidney, skin, liver, gall bladder, and blood vessels. It is associated with transient ischemic attacks, stroke, angina, myocardial infarctions, Alzheimer's disease, and hearing loss. Reported ocular blood flow abnormalities include reduced ipsilateral and pulsatile ocular blood flow, reduced flow to the optic nerve head and peripapillary retina, and an increased incidence of disc hemorrhage.
XFS appears to be a member of the family of conformational disorders, which arise from an abnormal arrangement of proteins that results in a harmful gain or loss of biological function, Dr. Ritch explained. Other conformational diseases include Alzheimer's disease, Parkinson's disease, Huntington's disease, cystic fibrosis, and type II diabetes, he said.
There are suggestions that XFS could have an infectious origin, Dr. Ritch said. There are reports of younger patients developing the condition after receiving corneal transplants from elderly donors. One suspect is herpes simplex, he said, citing a study that found the virus in the iris and anterior capsules of 13.9% of 64 eyes from patients with XFS but only 1.75% of 61 eyes from persons without the condition.
But there is "still insufficient evidence to suggest a causal relationship between any specific infectious agent and XFS," he said.
Whatever its cause, "non-IOP-lowering treatment modalities are potentially applicable to XFS," Dr. Ritch said.
And if the cause is identified, "we are looking at what is potentially a curable disease," he added.
Glaucoma 2006 was sponsored by The New York Eye and Ear Infirmary, the UMDNJ-Center for Continuing & Outreach Education, the New York Society for Clinical Ophthalmology, The Academy of Healthcare Education Inc., and CME2 , an independent subsidiary of Advanstar Communications Inc., publisher of Ophthalmology Times. Pfizer Inc. provided an unrestricted educational grant for the program.