contact lens case reports

Hydrops Helps

BY PATRICK J. CAROLINE, FAAO, & MARK P. ANDRE, FCLSA
MARCH 1999

Corneal hydrops is an anomaly that occurs in approximately five percent of keratoconus patients. The condition is characterized by spontaneous defect in Descemet's membrane and the overlying, endothelium, resulting in a sudden influx of aqueous into the stroma. The fluid results in immediate corneal swelling and opacification, with a dramatic reduction in visual acuity. Corneal perforation is extremely rare, but has been reported.

In time, the endothelial cells enlarge to cover the defect and ultimately bring about regeneration of Decemet's Membrane. Eventually, the endothelial pump clears the edema from the cornea. This sequence of events may take several months and a residual scar frequently remains. Occasionally, the edema persists, necessitating surgical intervention in the form of a corneal transplant.

Surprisingly, contact lens wear post hydrops is often more successful than prior to the rupture. This is due to the rather dramatic topographical changes produced by the massive influx of fluid into the cornea. Additionally, lens wear may be more tolerable due to a significant decrease in corneal sensitivity from the disruption of corneal nerve fibers.

The Example

Patient D.F. is an 18-year-old male with a four-year history of bilateral keratoconus. For the past three years he has been successfully wearing these RGP lenses: 63.75D (5.30mm) -20.50, 8.7, 20/50 OD and 55.25D (6.10mm) -13.50, 8.7, 20/30 OS. In September 1998, he suffered an acute hydrops in his right eye, which forced him to discontinue lens wear OD (Fig. 1).

Photokeratoscopy of our patient's right eye pre- and post acute hydrops clearly demonstrates the flattening phenomena (Fig. 2). Videokeratoscopy of the patient's right eye revealed an island of flattening over the area of resolving edema (Fig. 3). The patient was subsequently refit with a new RGP contact lens 52.75D (6.40mm) -16.50 8.7, 11.00D flatter than his previous right lens (Fig. 4).

Patrick Caroline is an associate professor of optometry at Pacific University and assistant professor of ophthalmology at the Oregon Health Sciences University.
Mark Andr� is director of contact lens services at the Oregon Health Sciences University.