Corneal irregularities can be treated and resolved without complicated surgery in some cases.
This article was reviewed by Christopher Rapuano, MD
For many ophthalmologists, epithelial basement membrane dystrophy (EBMD) or anterior BMD, Salzmann’s nodular degeneration, and band keratopathy are frequent offenders in clinical practices. Today, there are numerous techniques to identify these diseases, along with treatments that do not require complex surgeries.
EBMD is characterized by reduplicated epithelial basement membrane that causes loose adherence of the corneal epithelium to the stroma leading to recurrent painful erosions and/or irregular astigmatism on slit-lamp examination that may or may not be apparent on corneal topography or K readings.
However, clinicians should be alert to irregular astigmatism, according to Christopher Rapuano, MD, because it affects vision. In addition, if a cataract or refractive surgery is being considered, it can result in inaccurate K readings and incorrect intraocular lens power calculations, affect the postoperative quality of the vision, and worsen postoperatively, causing significantly decreased vision.
When diagnosed postoperatively, these issues become the surgeon’s problem, noted Dr. Rapuano, chief of the Cornea Service, Wills Eye Hospital, and professor, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia.
Picking up EBMD can be tricky in some cases, but Dr. Rapuano demonstrated that fluorescein staining will often make it readily apparent. When deciding whether or not to treat, Rapuano shared some pearls that might solve the dilemma.
“If there was no negative staining or irregularity on topography or K readings centrally, then the problem probably does not require treatment,” he explained. “Conversely, consider treating if the patient is symptomatic or awaiting cataract or refractive surgery and wait about six weeks before rechecking the biometry twice to ensure the stability.”
Treatment can consist of epithelial debridement alone, or debridement in conjunction with diamond burr polishing or excimer laser phototherapeutic keratectomy (PTK). The process of debridement includes removal of all loose or irregular epithelium and basement membrane with a cellulose sponge or blade.
Dr. Rapuano said he likes to perform diamond burr polishing, which begins with epithelial debridement. He then uses a 5-mm diameter diamond-dusted burr to polish Bowman’s layer uniformly over the entire cornea for about five to six seconds to ensure that all reduplicated basement membrane has been removed.
According to Dr. Rapuano, some patients who undergo this procedure may have transient haze postoperatively that can be alleviated with steroids.
The key when performing excimer laser PTK, after debridement, he advised, is treating the entire epithelial defect with a uniform ablation of only about 5 μm.