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Rare But, Serious Corneal Complications

The cornea is the clear window on the front of the eye. It bends incoming light rather dramatically to focus an image on the retina at the back of the eye enabling us to see. The cornea is constructed of overlapping layers of tight packed and orderly arranged collagen fibrils. Finally, there is an ionic pumping mechanism that maintains the delicate balance of fluid content that yields clear corneal tissue.

Pellucid Marginal Degeneration (PMD)

Pellucid Marginal Degeneration (PMD) is a painless non-inflammatory thinning of the cornea. It cause is unknown. Most patients are initially asymptomatic but the progression of the disorder leads to a slow and continuous distortion to the vision.

The first sign of the onset of PMD is associated with a rapid decline in the quality of vision. The central cornea appears normal while the inferior and peripheral corneal tissue thins. This thinning triggers in a distortion of vision usually resulting in a high degree of astigmatism.

Continued corneal changes result in increasingly distorted vision which can no longer be corrected by eyeglasses or soft contact lenses. Acceptable vision can only be obtained by wearing rigid gas permeable lenses. While providing a new smooth surface to the eye and dramatically improving vision, the fit of these lenses must be monitored closely to minimize the impact they exert on the delicate peripheral corneal tissue.

This specialized fitting requires the expertise of the experienced eye care professionals you will find at Parrelli Optical®