Contact Lens Case Reports
When Descemet's Membrane Ruptures in Keratoconus
By Patrick J. Caroline, FAAO, & Mark P. André, FAAO
Ruptures in Descemet's membrane, or acute hydrops, occur in approximately 5 percent of individuals who have keratoconus. The condition develops when extreme corneal thinning and stretching causes breaks or tears in Descemet's membrane and the endothelium. Aqueous from the anterior chamber flows through the breaks, resulting in diffuse stromal edema and eventually the formation of bullae in the epithelium. At its acute stage, visual acuity is often markedly decreased and the eye is mildly irritated due to the presence of the epithelial bullae.
Figure 1. Slit lamp images of the patient's right and left eye at initial presentation.
Figure 2. Visante OCT images of the right and left eyes.
The condition is self-limiting in most cases; over a course of five to 10 weeks, adjacent endothelial cells migrate across the rupture and secrete a basement membrane that slowly “pumps” the excessive fluid from the cornea. Following resolution of the edema, the cornea is often surprisingly clear and may have flattened dramatically. Additionally, the extreme edema can disrupt the corneal nerve fibers, rendering the cornea hyposensitive. As a result, the patient's condition is often improved post-hydrops.
A Recent Case
Our patient is a 28-year-old female with a 12-year history of bilateral keratoconus for which she has successfully worn GP lenses. In early December 2010, the patient presented with a six-hour history of sudden vision loss accompanied by mild irritation OS only. Visual acuity OS was count fingers at three feet. She also reported that her GP lens would not stay on her eye.
Slit lamp examination OS showed significant stromal thickening, diffuse corneal edema, and a number of epithelial bullae (Figure 1). We performed anterior segment OCT with the Visante OCT (Carl Zeiss Meditec, Figure 2) and diagnosed acute hydrops. The patient was placed on a hyperosmotic drop and ointment and informed of the frequent self-limiting nature of the condition. She was also informed that if the edema persisted or if residual scarring was excessive that a penetrating keratoplasty could be performed.
Figure 3. The patient's slit lamp and OCT appearance at her one-month follow-up visit.
At the patient's one-month follow up (Figure 3), little change was noted in her uncorrected visual acuity, her slit lamp findings or in corneal thickness. We will continue to monitor her monthly to see whether the cornea clears with time or whether keratoplasty may be necessary. CLS
Patrick Caroline is an associate professor of optometry at Pacific University. He is also a consultant to Paragon Vision Sciences. Mark André is an associate professor of optometry at Pacific University. He is also a consultant for CooperVision.