Eyeworld

EW CORNEA 30 September 2011 D istinguishing the various etiologies of recurrent corneal erosions will af- fect a surgeon's approach to treating them, accord- ing to two surgeons who spoke to EyeWorld on the subject. "Treatment is definitely going to be influenced by what's causing the problem," said Sonia H. Yoo, M.D., associate professor of clinical oph- thalmology, Bascom Palmer Eye In- stitute, Miller School of Medicine, University of Miami. Anterior basement membrane dystrophies and trauma cause most recurrent corneal erosions, and the treatments range from medical to surgical, depending on the patient and etiology. The patient's degree of discom- fort and the frequency of that dis- comfort helps Dr. Yoo decide on the level of aggression of the treatment. "If it's once a year, I might stick to medical treatment to get the pa- tient through that acute episode," she said. Medical treatment Patching can be used for patients who have traumatic corneal erosion, according to Jonathan B. Ruben- stein, M.D., vice chairman and Deutsch Family Professor of Oph- thalmology, Rush University Med- ical Center, Chicago. "Sometimes all these patients re- quire is an overnight patch for com- fort, which also tends to immobilize the upper lid and provide a quieter, more stable environment for the ep- ithelial cells to heal underneath the closed eye." Dr. Rubenstein added that if the erosion carries the risk of infection, an antibiotic drop or ointment may be used before patching the eye. "I like to use an antibiotic in ointment form because that way it stays around for awhile and helps to lubricate the surface, as well as pro- vide the antibiotic coverage," Dr. Yoo said. Dr. Yoo said she prescribes lubri- cating drops for patients with a frank epithelial defect. For traumatic abrasions that may require 2 or more days of heal- ing time, a bandage contact lens may be used, Dr. Rubenstein said. "It's easier for the patient to tol- erate, and it protects the epithe- lium," he said, adding that he prescribes a fourth-generation fluo- roquinolone to be used twice a day while the contact lens is in place. Once the epithelial defect is gone, Dr. Yoo tells patients to use preservative-free artificial tears fre- quently and a lubricating ointment at night. "I have a low threshold for plac- ing punctal plugs if the ocular sur- face appears to be dry," she said. "If the patient is very uncomfortable, I will consider placing a bandage con- tact lens to get him or her through the acute phase where I'm trying to get the epi defect to heal." Surgical intervention If a patient's infections have become severe and frequent enough, surgical intervention may be required. The top three interventions in- clude anterior stromal micropunc- ture, superficial keratectomy, and phototherapeutic keratectomy (PTK) with an excimer laser. According to Dr. Rubenstein, superfi- cial keratectomy would be used if the erosion is very widespread and the whole corneal epithelium is in- volved. When deciding between mi- cropuncture and PTK, surgeons should consider how many inter- ventions would be needed to quell the problem. "With dystrophies in particular, you might say you're going to do PTK, but the chance that this is going to reoccur and need another procedure down the road is high," Dr. Yoo said. "With a patient who has erosion due to trauma, the chance of success with PTK is high, and it's likely we will be able to take care of the problem with just one treatment." During the micropuncture pro- cedure, Dr. Yoo said she uses a 27- gauge needle, bent at the tip, to place micropunctures very close to each other. The proximity of the mi- cropunctures helps to seal down the epithelial sheath that grows over. The bent needle allows Dr. Yoo to control the depth of the puncture site, and she adds fluorescein to help identify the area she is targeting. Patients with anterior basement membrane dystrophy may need more than one treatment, which could be an advantage over the laser procedure. "Micropuncture has the advan- tage over PTK because it is less ex- pensive, it can be done right in the office chair, and it does not induce a significant refractive change," Dr. Yoo said, adding that special consid- eration needs to be paid to cases where the treatment area includes the pupil. PTK, which can induce refrac- tive changes, is more expensive be- cause it is done with a laser that needs to be used in the operating room. However, "the advantage of PTK is that there is less variability be- cause it's done with a laser instead of by hand, and it's more uniform than putting in micropunctures by hand," Dr. Yoo said. by Jena Passut EyeWorld Staff Writer Corneal erosions: Treatments range from patches to PTK C orneal erosions can result from a variety of conditions and lead to a chronic recurrent condition that can have a significant impact on a patient's life. Recurrent corneal erosions (RCE) can often be subtle and lead to episodes of pain with minimal clinical findings. I feel it is impor- tant to divide RCE into two major categories: 1) absent basement membrane (secondary to trauma), and 2) increased basement membrane (epithelial basement membrane degeneration [EBMD]) or other subepithelial substances (corneal dystrophies). It is criti- cal to divide the recurrent erosions by diag- nosis because the patients present differently and the treatment will depend on the diagnosis. RCE secondary to trauma often have subtle findings and can be missed because the patient may have pain without a com- plete epithelial defect. The patient may have a well-documented history of corneal trauma but may not recall an episode be- cause it happened months or even a few years prior to the recurrent erosion. The key to diagnosis in these patients is the history: pain in the middle of the night or upon awakening. These symptoms are diagnostic for RCE, and the clinician should perform a careful slit lamp exam to locate the area of impending erosion. In patients without a frank epithelial defect there often is abnor- mal epithelium over the area of absent basement membrane. Signs include micro- cystic changes in the epithelium, elevated epithelium that is best seen with negative staining with fluorescein, and loose epithe- lium that can be demonstrated with a moist cotton tip. This area of abnormal epithelium is the target area for treatment, and anterior stromal puncture (ASP) is often the proce- dure of choice. Patients with abnormal subepithelial material (dystrophies and degenerations) are usually easier to diagnose because of the appearance of the material in both corneas. The challenging diagnostic patient in this group is the subtle EBMD patient with an erosion. Often examination of the fellow eye for mild signs of EBMD is the key to the diagnosis. With the advent of ASP and photother- apeutic keratectomy (PTK) we have more options to treat patients with RCE. We have asked two cornea specialists, Drs. Ruben- stein and Yoo, to give us their treatment ap- proach to these patients. Edward J. Holland, M.D., cornea editor Corneal erosion Epithelial basement membrane degeneration Superficial keratectomy Source: Jonathan B. Rubenstein, M.D.

• Cover