FEATURE EWAP MARCH 2022 23 or rule out the cornea as the main site of pathology, he said. For example, in a patient with irregular astigmatism (ectasia, corneal scar, Salzmann’s nodule, etc.) and other ocular pathology (cataract, macular degeneration, etc.), he said a gas permeable lens over refraction will identify what the vision potential would be if the corneal shape and astigmatism were regular. “This will help us in counseling the patient and recommending the best next treatment modality,” Dr. Marvasti said. Dr. Houser said she wants to know the potential of the patient’s eye, whether that patient is having cataract surgery or not. “Gas permeable or scleral lenses over refraction are useful to determine what the eye can see beyond the irregular cornea,” she said. “Whether the corneal changes are from EBMD or another disease, you can put a hard contact lens on, do refraction, and know what the potential of the eye is if you could fix the cornea and tear film.” Dr. Houser uses this before cataract surgery because it helps tell her how much of the vision change is due to the cornea. Healing time and waiting before surgery Dr. Houser said she likes to wait about 6 weeks after treating EBMD before proceeding with cataract surgery. Treatment like superficial keratectomy may be used in these cases. “I tell patients 4–6 weeks, but Corneal topography revealing irregular astigmatism secondary to EBMD. Source (all): Amir Marvasti, MD Itotally agree that EMBD is often missed. The classic Map Dot Fingerprint appearance is not always so obvious. For my practice, prior to refractive or cataract surgery, I pay particular attention to the epithelium, endothelium, and the tear film. Clinical history is also very important, i.e., dry eye symptoms, RCE, dry eyes in the morning (suggestive of Lagophthalmos). Most Asians (especially Chinese) have shallower orbits and protuberant eyes which makes them more prone to exposure problems when they sleep and more likely to develop RCE especially if they have EBMD. Staining the cornea is a must. I agree with the authors to use less dye, avoid dropping too much BSS or Alcaine on the fluorescence strip. Look for staining irregularity and measure tear film break up time. I do not routinely do corneal mapping; I look at the topography on both refractive and cataract patients. If topography shows irregularity and the rest of the cornea looks good, I would then request an epithelial mapping. Hard contact lens is an excellent method to confirm that the patient has an irregular cornea; however, if I have to perform this, the problem is usually µuite significant. I would therefore stay away from multifocal IOLs and perhaps even toric lenses, because this most likely will not be a short-term or simple problem. I always recommend patients with EBMD who suffer from recurrent corneal erosion to have their RCE treated before cataract surgery. I personally use PTK (average Bowman’s membrane 8-10 µm), I usually do 10 µm ablation (after epithelial debridement) taking mostly the Bowman’s membrane. PTK has a very high success rate (in my experience 100%). I often perform the PTK with PRK with Mitomycin C but I warn the patient it may be less accurate. For other surgical options, epithelial debridement is more effective if performed with alcohol delamination.1 Diamond burr polishing is probably as effective as PTK. I usually use stromal puncture only as a postop treatment because I find it is least effective for preop treatment of EBMD. This is because you are only treating a regional area rather than the whole cornea; it will also leave scarring and affect vision especially if treatment is performed centrally. Most important of all, I tell the patient they have two diseases, the cataract/refractive and the basement membrane disease, and after surgery we may still have to address or treat the EBMD (if it is not already treated). Reference 1. Ewald M, Hammersmith KM. Review of diagnosis and management of recurrent erosion syndrome. Curr Opin Ophthalmol. 2009 Jul;20(4):287-91. doi: 10.1097/ICU.0b013e32832c9716. PMID: 19491682. ditors½ note\ Dr. hang declared no relevant financial interests. John So-Min Chang, MD Hong Kong Sanatorium & Hospital 8/F Li Shu Pui Block, Phase II, 2 Village Road, Happy Valley, Hong Kong john.sm.chang@hksh.com ASIA-PACIFIC PERSPECTIVES continued on page 18
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