Corneal Thickness Foreshadows Rare Eye Disorder

Fuchs Endothelial Corneal Dystrophy linked to early changes in corneal thickness

(RxWiki News) For patients with an uncommon, painful eye condition that can gradually lead to blindness, the ability to identify and treat it early could be key to management of the disorder.

Researchers have found that changes in corneal thickness happen in the early stages of Fuchs' Endothelial Corneal Dystrophy (FECD), a condition in which the cornea swells and could lead to the need for a corneal transplant. Identifying the changes before the swelling occurs could lead to more effective early interventions.

"Talk to an ophthalmologist about early intervention."

Jonathan Lass, MD, Charles I Thomas Professor, chair of the Case Western Reserve University Department of Ophthalmology and Visual Sciences, and director of the University Hospitals Eye Institute, noted that the new evidence suggests that patients with the condition should receive regular checks to measure corneal thickness to ensure prompt and appropriate treatment.

This is important because many patients with the condition wait to see an ophthalmologist during a critical period when the cornea is swollen and vision already blurred.

Ophthalmologists are recommended to use ultrasonic technology to measure possible progressive thickening of the cornea. In healthy eyes, the cells that line the rear surface, called the endothelium of the cornea, stop excess fluid from accumulating so that the cornea stays transparent. With FECD, the endothelial cells deteriorate and die, resulting in fluid build up that can cause painful swelling and cloudy vision. In some cases it eventually leads to blindness. It is the most common reason for corneal transplantation in the U.S.

It was previously suspected that in the disease's earlier stages, the cornea remained clear and the thickness did not change. Researchers came to another conclusion during the current study, however.

Investigators studied 1,610 eyes from a subset of FECD cases, relatives of FECD patients, and unrelated individuals without the eye condition through the FECD Genetics Multi-Center Study, which took place at more than 30 medical centers. They then examined central corneal thickness of the eyes, and considered the interaction between the severity of FECD on corneal thickness in patients with and without swelling.

They found that the cornea experiences gradual swelling with increasing severity of the eye disorder, prompting it to gradually thicken. Monitoring these changes, they concluded, could lead to a more sensitive measure of FECD progression. Researchers currently are working to identify the genes that cause the unusual disease.

Dr. Chris Quinn, an optometrist with Omni Eye Associates, said the study was not surprising, nor likely to change clinical practice.

"The recommendation here that patients with Fuch's have annual corneal thickness measurements is in my opinion silly. Since no intervention is contemplated if a patient has increased corneal thickness, but no other symptoms or reduced vision, there is no really good reason to perform corneal pachymetry (ultrasound) routinely," Dr. Quinn said.

"It is already well know that people with Fuch's may have increased corneal thickness. There may be some limited value in determining the rate of progression of the condition by measuring corneal thickness early in the disease but in my experience, this is rarely helpful."

The study, funded by the National Eye Institute, Research to Prevent Blindness, and the Ohio Lions Eye Research Foundation, was recently published in the journal Archives of Ophthalmology.

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Review Date: 
April 14, 2012