REFRACTIVE SURGERY COMPLEX CASE MANAGEMENT s HEADLINEPERSISTENT LASIK FLAP INTERFACE FLUID AFTER DSAEK PROCEDURE IOP measurement is key to this case. BY MARK S. GOROVOY, MD; RICHARD S. HOFFMAN, MD; ROBERT K. MALONEY, MD; AND ALAN N. CARLSON, MD A Figure 1. Initial anterior segment OCT (AS-OCT) shows a small gap in the LASIK flap. B A B Figure 2. AS-OCT 10 days after the image shown in Figure 1 demonstrates increased Figure 3. After a rebubbling procedure with venting incisions, AS-OCT shows a persistent— fluid in the LASIK flap (A). Slit-lamp photograph taken at the same visit also shows a but smaller—cleft in the LASIK flap (A), and slit-lamp photography reveals a subtle gap in the gap in the LASIK flap (B). LASIK flap (B). CASE PRESENTATION A 47-year-old black woman with a remote history of LASIK and steroid-responsive The patient’s extensive history included trabeculectomy in both eyes and the advanced glaucoma in both eyes was referred by the Duke Glaucoma Service to the implantation of a Baerveldt 350-mm2 implant (Johnson & Johnson Vision) in her Cornea Service because of corneal decompensation involving her right eye.1 right eye, with a subsequent exchange for a Baerveldt 250-mm2 implant owing FEBRUARY 2018 | CATARACT & REFRACTIVE SURGERY TODAY 19 s REFRACTIVE SURGERY COMPLEX CASE MANAGEMENT to the formation of a large bleb. Upon presentation small cleft of fluid was observed in the LASIK flap A week later, visual acuity in the patient’s right to the Cornea Service, the visual acuity in her right interface (Figure 1). Visual acuity measured 20/400, eye remained poor—count fingers at face—and the eye measured 20/400, with a visual potential of and the IOP measured 32 mm Hg, suggesting a IOP measured 19 mm Hg. Slit-lamp photographs 20/40 based on her examination prior to corneal mechanism similar to interface fluid syndrome (IFS) were taken at this time (Figure 3). Topical glaucoma decompensation. after LASIK.2,3 therapy was restarted in an attempt to further lower The patient underwent a triple procedure The patient was unable to tolerate topical glau- the IOP. Over the subsequent weeks, the patient combining cataract removal, IOL implantation, coma medications, and the cleft of fluid worsened discontinued all topical glaucoma drops on her own and Descemet stripping automated endothelial over the subsequent week (Figure 2). She was because of ocular irritation. Her examinations have keratoplasty (DSAEK). The postoperative course was taken back to the OR. The surgeon attempted to been relatively stable, with a poor visual acuity (cur- complicated by primary graft failure. A second graft drain the fluid through venting incisions while rently 200E at 4 feet), an IOP in the low 20s mm Hg on was placed, but it failed shortly after additional adding air in a rebubbling procedure, releasing oral acetazolamide, and a persistent fluid cleft. glaucoma surgery consisting of tube removal and fluid and collapsing the interface. Acetazolamide How would you proceed? laser endocyclophotocoagulation. was administered intravenously during the pro- A third DSAEK procedure was performed. On post- cedure, and the patient was sent home with oral —Case prepared by Morgan R. Godin, MD; operative day 1, the graft was fully attached, but a acetazolamide 500 mg. Nicole Fuerst, MD; and Melissa B. Daluvoy, MD Baerveldt 350-mm2 glaucoma implant diffuse lamellar keratitis and treated in the inferior quadrant. Once the aggressively with topical steroids, only IOP had been controlled for 6 weeks, to experience worsening optic nerve allowing the tube ligature time to damage because of undiagnosed dissolve, it would then be possible steroid-induced glaucoma in the MARK S. GOROVOY, MD to assess the patient’s DSAEK status presence of interface fluid.4 accurately. Normalization of the IOP In this case, if the IOP has been IFS presents as elevated IOP with should eliminate the LASIK flap cleft measured centrally, over the area of fluid accumulation in the LASIK flap and, I would hope, allow verification interface fluid, the actual IOP may interface as well as falsely low IOP that the DSAEK graft was viable after be above 40 mm Hg as opposed to readings. Primary endothelial failure the cornea had cleared. Under no 19 mm Hg, and the patient may be typically causes diffuse corneal edema circumstances should further corneal losing vision from glaucoma as well without interface fluid, and IOP read- surgery be performed before the IOP as from the decompensated cornea. ings are accurate. Clearly, this patient normalizes. For that reason, in the presence of is an example of the former scenario, interface fluid, all IOP measurements and she was most likely misdiagnosed should be taken with a Tono-Pen in three times as suffering from primary the peripheral cornea. IFS can result DSAEK failure. Her history of three from corneal endothelial dysfunc- glaucoma procedures is highly unusu- tion (a failed graft) or from elevated al, especially the exchange of shunts IOP; an accurate pressure reading will and, finally, the shunt’s explanation assist with the differential diagnosis. for a cyclodestructive procedure. Because of this patient’s problemat- My recommendation is first to RICHARD S. HOFFMAN, MD ic history with topical glaucoma ther- obtain an accurate IOP reading, apy, if her IOP is dangerously high, I and to do so I would use the Model Before assessing the next step for would recommend that she undergo 30 Pneumatonometer (Reichert this patient, it would be essential to a repeat tube shunt procedure. My Technologies). I would expect the IOP learn how her IOP was calculated. hope would be that this interven- to be very high. It would be impera- Measuring IOP with either appla- tion would help to resolve the IFS. tive to address the elevated IOP nation tonometry or a Tono-Pen Unfortunately, if IFS is allowed to before pursuing further corneal evalu- (Reichert Technologies) over the persist for months, many patients will ations or procedures. central cornea yields an artificially low develop permanent haze in the flap Assuming that the IOP is high, value in eyes with IFS.1 Patients with interface from keratocyte hydropic my preference would be to place a IFS can be misdiagnosed as having degeneration.2 Ultimately, these 20 CATARACT & REFRACTIVE SURGERY TODAY | FEBRUARY 2018 REFRACTIVE SURGERY COMPLEX CASE MANAGEMENT s patients will require full-thickness optic atrophy because of this unrecog- to ascertain whether or not a patient corneal transplantation to resolve nized elevated IOP. Figure 3 appears to has ever undergone LASIK. both the stromal haze and any endo- show diffuse microcystic edema, which I would also point out that vit- thelial failure.5 suggests that the true IOP is signifi- reoretinal surgeons who have a low cantly higher than indicated. threshold for debriding the corneal Draining the fluid in this case did epithelium to improve intraopera- not resolve the fluid pocket because it tive visualization are more likely to did not alter the fundamental physi- encounter healing problems owing to ology. This patient needs to have her the LASIK flap. Surface healing may IOP reduced to the lowest possible be slower due to flap innervation and level. An IOP measurement on the relative neurotrophism, and fluid may peripheral cornea will reveal whether collect in the interface because of ROBERT K. MALONEY, MD the pressure in the eye is elevated. If only moderately elevated IOP, which, so, a replacement tube with aggres- as the panel noted, can then be chal- The key features of this case are a sive lowering of the IOP, even at the lenging to measure accurately. n compromised endothelium from a expense of a large bleb, is indicated. 1. Hamilton DR, Manche EE, Rich LF, Maloney RK. Steroid-induced glaucoma DSAEK procedure, fluid collected in With a true IOP of 15 mm Hg or less after laser in situ keratomileusis associated with interface fluid. Ophthalmology. the original LASIK flap interface, an and a somewhat functional DSAEK 2002;109(4):659-665. 2. Dawson DG, Schmack I, Holley GP, Waring GO 3rd, Grossniklaus HE, Edel- IOP apparently in the high normal graft, the interface fluid pocket hauser HF. Interface fluid syndrome in human eye bank corneas after LASIK: range, and a hazy cornea. IFS develops should resolve on its own. causes and pathogenesis. Ophthalmology. 2007;114(10):1848-1859. 3. Randleman JB, Shah RD. LASIK interface complications: etiology, manage- when aqueous crosses the endothe- ment, and outcomes. J Refract Surg. 2012;28(8):575-586. lium and collects in the potential 4. Galal A, Artola A, Belda J, et al. Interface corneal edema secondary to steroid-induced elevation of intraocular pressure simulating diffuse lamellar space that is the LASIK flap interface. keratitis. J Refract Surg. 2006;22(5):441-447. Aqueous can cross the endothelium 5. Hoffman RS, Fine IH, Packer M. Persistent interface fluid syndrome. either because elevated IOP drives it J Cataract Refract Surg. 2008;34(8):1405-1408. across or because endothelial com- promise prevents adequate drying SECTION EDITOR ALAN N. CARLSON, MD of the stroma through the normal n Professor of Ophthalmology and Vice Chair, endothelial pump function. This case ALAN N. CARLSON, MD Departmental Development, Duke Eye Center, appears to have features of both Durham, North Carolina mechanisms: the endothelial cell The frequency with which I am n [email protected]; alancarlsonmd.com density is reduced after DSAEK, and seeing late-onset problems with n Financial disclosure: None acknowledged the patient has a history of steroid- LASIK flap interfaces is increasing. induced glaucoma and is presum- Several key features of this case are MARK S. GOROVOY, MD ably still taking steroids because of notable.