Coping with Corneal Hydrops
BY WILLIAM L. MILLER, OD, PHD, FAAO
Occasionally all of us have certain ocular conditions show up in our offices in clusters. Over the last week this has been the case in our Cornea and Contact Lens Service with patients suffering from acute corneal hydrops.
Corneal hydrops typically occurs in about 3 percent of all keratoconus patients, although it also occurs in patients who have pellucid marginal degeneration, Terrien's marginal degeneration and less frequently with keratoglobus.
Keratoconus patients at a higher risk for developing corneal hydrops include those who were young and/or had poor visual acuity at the time of diagnosis, those who have severe allergic disease or those who have rapid keratoconus progression.
Corneal hydrops manifests when the barrier function and posterior limiting lamina are compromised, allowing fluid to flow anterior into the stroma and ultimately into the epithelium (Figure 1). The corneal edema can last weeks to months, hindering patients' quality of life.
Keratoconus patients will present with decreased vision, varying levels of pain, conjunctival hyperemia and photophobia. Typically, corneal hydrops presents in more severe cases of the disease process and requires an acute treatment and management plan. It also has ramifications for future GP lens wear and possible surgery. At the acute visit, apprise patients of the reason for their vision loss and pain.
Treatment options include in-office homatropine or scopolamine for pain management. A non-steroidal anti-inflammatory topical three to four times a day will help control pain and inflammation. You may also add a hyperosmotic topical solution during waking hours and a hyperosmotic ointment at night. Both control the epithelial edema and resultant pain. Exact dosing of the hyperosmotic solution depends on corneal hydrops severity.
Figure 1. An OCT image of corneal hydrops in a 25-year-old patient.
Patching is a lesser used method to relieve pain. More practitioners opt for bandage contact lenses.
Avoid steroid application because it slows corneal healing and may lead to rare corneal perforations. However, some practitioners use steroids to decrease scarring when the edema is in its waning stages.
Other treatments include intracameral injection of specific gases, which may serve to tamponade against the endothelium and prevent aqueous movement into the stroma. The disadvantage to some of these procedures may include toxicity of the gas to the endothelium or long half-life of the gas within the anterior chamber, which may lead to a secondary glaucoma.
After the Event
The cornea will flatten after the hydrops episode. In many patients the residual scarring area falls outside the paracentral region, thus allowing patients to regain vision. Patients' contact lenses will most likely need refitting after the hydrops due to the change in corneal shape.
Although corneal surgery isn't the end result for every corneal hydrops patient, it's prudent to start discussing surgical options with patients and outlining the advantages and disadvantages. Some studies indicate that between 18 percent and 60 percent of corneal hydrops patients will need a resultant penetrating keratoplasty. The longer the corneal hydrops remains, the greater the incidence for a penetrating keratoplasty. CLS
Dr. Miller is the Director, Cornea and Contact Lens Service at the University of Houston College of Optometry. He is a member of the American Optometric Association and serves on its Journal Review Board. You can reach him at firstname.lastname@example.org.