Eyeworld

80 Healthy patient develops rare complication T he LASIK surgery appeared to go off without a hitch in a young, healthy moderate myope. Weeks later, how- ever, practitioners found that they were dealing with choroidal neovascularization, ac- cording to Sherry J. Bass, O.D., dis- tinguished teaching professor, SUNY State College of Optometry, New York. Investigators recently reported on the case and related literature re- view in the August 20, 2010 e-issue of Optometry. While choroidal neovasculariza- tion is commonly linked to age-re- lated macular degeneration, as well as some inflammatory conditions like ocular histoplasmosis and ac- quired maculopathies, there has been almost no connection to LASIK previously reported. "If you look at the literature, the incidence of this happening after LASIK is extremely rare," Dr. Bass said. "Of 30,000 pa- tients, one was reported to have this develop after LASIK (without predis- posing factors)." It was with this in mind that investigators decided to publish the case. "The reason that we reported it was because this was a patient who had no predisposing ab- normality in the macula," Dr. Bass said. "She was a routine myope (–5 D), not a very high myope, and de- veloped this 6 weeks after LASIK." Occurring out of the blue The patient's pre-exam was unevent- ful, she had no history of any prob- lems, and the LASIK itself went off without any complications. Then after 6 weeks, she presented with distortion in her left eye. "We looked at her retina and she had fluid in her macula," Dr. Bass said. "First we did an OCT [optical coher- ence tomography] and then a fluo- rescein angiography, and the OCT demonstrated that a possible neo- vascular net had developed." Fluo- rescein confirmed that she had a classic choroidal neovascular net be- neath her macula. Practitioners referred the patient to a retinal specialist who treated her with photodynamic therapy and tri- amcinolone. She ultimately did very well. "Her visual acuity at the time that she developed this net was 20/50, and over the course of 3 months she improved to 20/20," Dr. Bass said. "She had no long-lasting effects." Investigators were able to find just one other case in the literature in which a LASIK patient with no predisposing factors developed this condition. "This patient had a hy- peropic refractive error and didn't have any retinal abnormalities," Dr. Bass said. There are two theories on what may lead to neovascularization post- LASIK in otherwise normal eyes. "The main theory is that during the course of LASIK when the surgeon applies the microkeratome to create the flap, the eye is exposed to very high pressure," Dr. Bass said. "Most eyes can tolerate that pressure with- out a problem, but if there is an eye that has some kind of congenital weakness in Bruch's membrane, that high pressure, even for a very short period of time, can possibly cause a break in Bruch's membrane." A second theory centers on the photoablation process itself. "The other possibility is that the photoab- lation with the laser can create these waves that travel through the vitre- ous and hit the retina," Dr. Bass said. "In a normal eye it doesn't cause any damage—it's a very mild force— but maybe in an eye that has some type of a weakness it's enough of a force that it could cause a break in Bruch's membrane." Getting informed consent Despite the fact that this is an ex- tremely rare complication, Dr. Bass urges practitioners to take heed with regard to consent forms. "I have looked at a number of consent forms from a number of practices and they don't mention that if the patient has a history of macular problems, there could be a risk of this developing," Dr. Bass said. "In any patient, doc- tors should mention this when they're listing all of the possible things that could happen. Although it's extremely rare, there is a possibil- ity that there could be the develop- ment of a posterior segment abnormality in the form of choroidal neovascularization." In this particular case, Dr. Bass considers herself lucky that all even- tually turned out well. "The next day this young lady's brother came in and said, 'It wasn't on the con- sent form that this could happen,'" Dr. Bass said. "Thankfully, when her vision returned to normal, he no longer had any reason to be upset because there were no long-lasting effects." Dr. Bass thinks it is important for patients to understand that this complication is a possibility, how- EW REFRACTIVE SURGERY 80 March 2011 by Maxine Lipner Senior EyeWorld Contributing Editor On the lookout for choroidal neovascularization after LASIK Although choroidal neovascularization is traditionally linked to AMD (pictured here), a study examined a case that appeared in a healthy woman after LASIK Source: Kang Zhang, M.D., Ph.D. continued on page 81

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