OCT 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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54 EW CATARACT October 2012 Treating ABMD in premium IOL patients by Vanessa Caceres EyeWorld Contributing Writer Cornea irregularities should be addressed pre-op P atients with anterior basement membrane dystrophy (ABMD) present with a number of corneal and visual challenges. However, if that patient is going to have cataract surgery and possibly a premium IOL implantation, treat- ment becomes even more challeng- ing, said Bonnie An Henderson, M.D., partner, Ophthalmic Consultants of Boston, and EyeWorld cataract editor. "One of my unhappiest patients was a woman with ABMD who underwent cataract surgery," Dr. Henderson said. "The corneal find- ings were fairly mild and because she had other serious ocular comor- bidities, I did not focus the discus- sion on the possible post-operative problems that could occur from ABMD but rather on her significant glaucoma and macular disease." The patient had uneventful cataract sur- gery but then had a good deal of pain at week 1 post-op due to epithelial loss. "Because I had not discussed the risks of ABMD and variable healing, she was very unhappy with her outcome and care even though her surgery went well and her final vi- sion was 20/20," Dr. Henderson said. By adding a premium IOL to the surgical mix, you set the bar higher in patients whose expectations are usually already high, said David D. Verdier, M.D., Verdier Eye Center, Grand Rapids, Mich. For this reason, careful pre-op diagnosis and treatment are crucial in patients with ABMD who want to have a premium IOL. Explaining the condition A patient who has anything but the mildest form of ABMD will require treatment before undergoing cataract surgery and premium IOL implantation, said Steven G. Safran, M.D., Lawrenceville, N.J. The process of clearing the cornea can take 2-3 months. "That time is a small investment to make," Dr. Safran said. Patients who do not want to wait those few months to treat ABMD are probably not good candidates for a premium IOL, Dr. Safran said. However, he finds his patients are open-minded about treatment. "I tell patients it's like painting a house. You'd be stupid to do it with leaves blowing against the paint," Dr. Safran said. Another good analogy for ABMD and lens surgery is likening it to a moving target, Dr. Verdier said. "If it's more than a very mild case of ABMD, you're going to have some irregular astigmatism and areas of involvement that change over time." Without pre-op treatment, the ABMD patient may experience poorer visual quality post-cataract surgery, said Natalie Afshari, M.D., director, Cornea and Refractive Surgery Fellowship Program, and assistant professor, Department of Ophthalmology, Duke University, Durham, N.C. Additionally, a lack of pre-op treatment can make it diffi- cult to obtain accurate keratometry measurements, Dr. Henderson said. Confirm, treating, and to scrape or not to scrape? When the ABMD patient presents for cataract surgery, Dr. Safran first confirms the true source of the visual problem. "Sometimes it's the cornea and not a cataract causing problems," he said. He has also seen the reverse situation: "I've also seen patients unhappy after cataract sur- gery who have not had their corneal problems addressed," he said. Dr. Safran commonly finds that ABMD patients also have other con- ditions such as pannus, blepharitis, or Demodex mites, all of which he will treat as necessary with doxycycline, Restasis (cyclosporine ophthalmic emulsion, Allergan, Irvine, Calif.), or tea tree oil. Drs. Safran and Verdier typically scrape the cornea pre-op and per- form a superficial keratectomy. Dr. Afshari performs a phototherapeutic keratectomy (PTK), a laser smooth- ing treatment. Although some patients can get by without PTK, Dr. Afshari tends to be more conservative with her approach in patients who want a premium IOL. "Perfection is the goal, especially with those patients," she said. Dr. Safran tries to limit scraping to before surgery as he finds that scraping after cataract surgery can induce a change in refraction. How- ever, Dr. Henderson prefers not to scrape the cornea before surgery in mild ABMD cases. She instead dis- cusses with patients the associated potential risks for pain and blurred vision, which might cause the need for scraping after surgery. She also discusses the possibility of a refrac- tive surprise caused by the difficulty in measuring keratometry values. "Scraping before surgery is a reasonable approach. However, I have found that the majority of patients who have ABMD do not develop post-operative issues and have accurate K measurements," Dr. Henderson said. However, if K measurements are inconsistent pre-op, Dr. Henderson will go ahead and scrape the cornea to obtain reproducible and accurate measurements. "Also, if a pre-opera- tive topography shows a significant irregular surface, then the patient may benefit from scraping," she said. Dr. Henderson finds it useful to perform the K readings for these patients in up to four different methods—manual, auto, noncontact biometry, and topography—to com- pare their values and obtain consis- tency. "If the values differ even after repeated measurements, then I do not implant a toric or presbyopia- correcting IOL," she said. Post-treatment considerations Once the ABMD is treated, the surgeon can usually proceed with premium IOL implantation. "Once it's stabilized, you can do what you want," Dr. Safran said. Still, these patients require some extra monitor- ing during and after surgery. Dr. Verdier prefers not to use multifocal IOLs in patients who have had ABMD because of a possible risk for increased glare and decreased contrast sensitivity. He instead recommends a toric lens or Crystalens (Bausch + Lomb, Rochester, N.Y.). "The problem is that 50% of us will get ABMD," Dr. Verdier said. "When you choose multifocal patients, they may not have ABMD, but by age 80 or 85, more patients will have it." Dr. Henderson will be careful during cataract surgery with patients who have mild ABMD to avoid trauma to the epithelium and keep the epithelium well lubricated. She uses a dispersive viscoelastic to help continued on page 56 These images show a patient with ABMD who was told she would need a toric IOL. The images show her topography, her cornea, and lids. The patient had meibomitis and Demodex mites. The final images show her presentation after a superficial keratectomy. The patient was eventually happy with a Crystalens Source: Steven G. Safran, M.D.

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