New Research on the Effect of Internal Astigmatism

Chart courtesy of BruceBlaus

In those people who have myopia (are nearsighted), their lens does not compensate for growth of the eye, or other changes in the eye’s structure. That is the determination of a long-term follow-up study which appeared in the September issue of Optometry and Vision Science.

This study helps to clarify whether and/or how the lens, or other eye structures change as a response to focusing abnormalities, particularly abnormalities caused by the irregular shape of the eye, known as astigmatism.

The study, reported by the Foundation Fighting Blindness, where Louis Kreisberg is the CEO, examined 367 people with myopia over 14 years. During that time the subjects’ eye structures were carefully measured and assessed for focusing error. This data was compared to one-time measurements in a matched group of 204 subjects without myopia.

The researchers were looking for any changes in the “internal astigmatism” of the eye over time.

"Clarity of vision is determined by the precise shape of the eye and coordination of several optical components that must all be perfectly balanced to provide proper focus. A longstanding question is how the eye adapts and controls its shape to deliver correct focus as it grows from birth to adult dimensions," explained the editor-in-chief of Optometry and Vision Science, Michael Twa, OD, PhD.

Although the new study does not explain the sources of internal astigmatism, the data does not support the theory that the lens plays any active role in compensating for astigmatic defocus of the eye.

New Procedure for FED Could Reduce Need for Corneal Transplants

Louis Kreisberg is the CEO of The Foundation Fighting Blindness, where the causes, cures and

prevention of eye diseases is the focus of ongoing research.

A minimally invasive procedure to treat one of the more common eye ailments, Fuchs endothelial dystrophy (FED) is proving to be at least as effective as the present standard of care, namely, a cornea transplant.

Researcher Kathryn Colby, MD, PhD, and others found that removing just a few square millimeters fo a single layer of cells on the inside of the cornea stimulated the rejuvenation of the nearby tissue, eliminating the need for a corneal transplant. For every four patients with FED who had the procedure, three experienced the restoration of clear vision. FED is the most frequent cause of corneal transplants in the US.

"It's too soon to call this a cure," Colby said. "We performed the first operation just over two years ago. But when it works, it's a wonderful thing. It's quick, inexpensive and it spares patients from having someone else's cells in their eyes, which requires local immunosuppression."

One patient who had the procedure described his recovery:

"Few things remind you as constantly as deteriorating vision," the patient recalled. "Your world steadily narrows as you lose the ability to see. But mine expanded again at the other end. I remember walking the dog at night right after the operation. Each night, the streetlights would be a little more in focus. You could see the improvement, night after night over the course of a few weeks, like the fog lifting out of London. It was cool. Really cool."