EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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12 EW NEWS & OPINION April 2012 Facing interface fluid after LASIK, RD repair by Vanessa Caceres EyeWorld Contributing Editor Surgeon shares how he handled unusual case Y ou never know what challenges certain cases will present. Recently, Steven G. Safran, M.D., Lawrenceville, N.J., handled a case where a 50-year-old female presented with interface fluid in the cornea; at one point, her angle was closed and her iris was plastered to her cornea. The patient had LASIK 3 years before and a repaired retinal detach- ment (RD) fixed with a pars plana vitrectomy and an air fill not long before Dr. Safran saw her. The patient's problems began after the air fill; the referring retinal specialist was concerned about the patient's elevated IOP and poor visi- bility through the cloudy cornea. Figure 1. A narrow angle at presentation Other surgeons weigh in Here's what some other surgeons think about Dr. Safran's handling of this unusual case. In my personal experience, inter- face fluid accumulation from high IOP has been in the early healing phases post-LASIK, such as when the IOP goes up secondary to steroid use within the first month post-op. I personally have not seen a case of pressure-induced stromal keratitis 3 years post-op like this case. This shows poor healing of the flap to the residual stromal bed post-LASIK. The OCT is also very revealing in this case. I have seen photos of this condition, but I have never seen it so well documented as with high-definition OCT. Michael Wong, M.D. Princeton, N.J. When you have a completely air/ gas-filled eye, you cannot see much of anything. The patient may not necessarily have had a gas overfill, but perhaps the patient was not positionally compliant following her RD repair. Typically, the post-op RD patient is asked to maintain a face-down position and to avoid the supine position so long as the gas bubble remains in the eye. If a patient has areas of zonular dehiscence and he/she is in the supine position following surgery, then the patient can end up with gas in the anterior chamber without having had a gas "overfill" per se. I suspect the posterior pressure from the gas in the posterior seg- ment, the pupillary blockade, the angle closure, and the gas in the anterior chamber in the setting of previous LASIK all may have con- tributed to the phenomenon that Dr. Safran described. Andrew Moshfeghi, M.D. Palm Beach Gardens, Fla. I believe that the expansive gas resulted in extreme elevation of IOP, which resulted in fluid influx into the cornea that deposited in the LASIK interface. Dr. Safran has documented with OCT this flap thickening during times of high IOP. This deposition of fluid may have masked the accuracy of IOP measurements, resulting in a falsely low IOP. The falsely low IOP may have delayed the retinal sur- geon from performing the surgical intervention of gas removal. William F. Wiley, M.D. Cleveland Contact information Moshfeghi: amoshfeghi@med.miami.edu Wong: mwong2020@gmail.com Wiley: drwiley@clevelandeyeclinic.com Figure 2. Both angles at presentation Figure 3. The cornea with edema in the flap interface at the time of presentation Source (all): Steven G. Safran, M.D. Dr. Safran shared the case with EyeWorld to demonstrate, among other things, how ocular coherence tomography (OCT) can help manage difficult cases. "It was the OCT that allowed me to make the diagnosis and come up with a treatment plan because I couldn't see what was going on through the cloudy cornea," he said. At presentation At presentation, the patient had an IOP of 42 mm Hg in her right eye and 16 mm Hg in her left eye. She had corneal edema when he saw her. Her pachymetry was 640 with ultra- sound in the right eye and 540 in the left eye. Because of her elevated IOP, the cornea should have been thinner, not thicker, he said. "Over the years I've taken care of a few patients who have had LASIK and had precipitous drops in vision associated with minimal corneal inflammation or pressure elevation," Dr. Safran said. "I've always assumed that this was due to fluid in the interface that could not be seen but caused the vision to get much worse than looking at the cornea would suggest ... in other words, that a potential space existed that could fill with fluid and lead to degradation of vision even years after surgery." Dr. Safran used OCT to get a closer look at what was happening (Figures 1-3). Her eye with the ele- vated IOP had 40 microns of fluid in the interface whereas the other eye did not. The flap was also thicker or swollen in the eye with the fluid. "Fluid can get in the interface, and flap edema can occur in these eyes and degrade vision under these circumstances, making the cornea more labile under stress," Dr. Safran said. OCT helped Dr. Safran view a closed angle. Clinical images also helped Dr. Safran see congestion, the air bubble, and an outline of the LASIK flap. "Her pupil was dilated, and she had punctate keratopathy and microcysts in the cornea, so I continued on page 14