CONSULTATION SECTION

Refractive Surgical Question Edited by Rudy M.M.A. Nuijts, MD, PhD

In June 2004, a 48-year-old man had laser in situ keratomileusis (LASIK) in both eyes. According to the patient’s charts, the preoperative corrected distance visual acuity (CDVA) was 20/25 with +1.00 3.25  175 in the right eye and 20/25 with +0.75 3.00  165 in the left eye. In July, he had an enhancement in the right eye because of undercorrection (+0.25 2.25  180). Postoperatively, the refraction in the right eye was +1.00 1.25  171. In August 2005, the patient had a second enhancement. In May 2009, the residual refraction was +2.00 1.75  7. In June 2011, a flap lift was performed in the right eye with additional use of mitomycin-C (MMC) because of progressive epithelial ingrowth. Afterward, the patient could function adequately with the use of a contact lens. In August 2013, the patient scheduled a consultation at another hospital in the Netherlands because of a corneal ulcer with a positive Pseudomonas culture in the right eye. In February 2014, the patient was referred to our department and the CDVA was 20/100 with +8.00 6.00  150 in the right eye and the uncorrected distance visual acuity (UDVA) was 20/25 in the left eye. Slitlamp examination showed epithelial ingrowth at the periphery of the flap at 3 o’clock and 7 o’clock (Figures 1 and 2). The flap diameter appeared to be 9.5 mm. There was an extensive stromal scar with stromal thinning in the temporal lower quadrant of the cornea. Figure 3 shows anterior segment optical coherence tomography (AS-OCT) of the right eye.

Figure 1. Slitlamp photograph of the right eye. Q 2014 ASCRS and ESCRS Published by Elsevier Inc.

Figure 2. Slitlamp photograph of the epithelial ingrowth at 3 o'clock.

Scheimpflug photography showed irregular astigmatism and a minimum corneal thickness of 463 mm (Figure 4). A trial with scleral contact lenses was not successful because of contact lens intolerance and practical issues stemming from the patient’s work as a police officer. How would you treat the epithelial ingrowth and stromal scar in the right eye? Would you perform a flap amputation and wait for reepithelialization with a postoperative contact lens fitting? Could one still use a topography-guided excimer laser technique to remove the scar in combination with an anterior lamellar procedure? Would you perform an anterior lamellar keratoplasty or deep anterior lamellar keratoplasty (DALK)? If yes, how would you handle the preexisting flap dimensions and epithelial ingrowth in the periphery? Or would you perform an excimer laser and femtosecond laser–assisted (mushroom-shaped) keratoplasty?

Figure 3. Anterior segment OCT of the right eye. 0886-3350/$ - see front matter http://dx.doi.org/10.1016/j.jcrs.2014.07.018

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CONSULTATION SECTION

Figure 4. Scheimpflug photography of the right eye.

- At present, the patient's CDVA is 20/100 with a high hyperopic and astigmatic refraction. The cornea has an extensive scar extending into the visual axis with a large area of epithelial ingrowth at the 3 o'clock position (nasally) and a smaller area at 7 o'clock. Corneal topography shows a highly irregular cornea with marked with-the-rule astigmatism, an anterior depression temporally, and elevation nasally. Anterior segment OCT confirms loss of tissue temporally that extends into the visual axis as well as almost full-thickness stromal scarring. Epithelial ingrowth that is nonprogressive represents a focal area of apoptosed epithelial cells.1 Cells other than progenitor stem cells have a finite culture rate, after which proliferation stops. The use of MMC in treating late epithelial ingrowth is highly unusual and unnecessary. Removal of the ingrowth and placing interrupted 10-0 nylon sutures to close a potential fistula and eliminate recurrence is a good method of permanently eliminating epithelial ingrowth.2 Because severe scarring extends into the visual axis and is associated with thinning and irregular astigmatism, I believe the most definitive treatment for visual rehabilitation in the right eye is DALK. The patient is a police officer and will have to be cautioned about the risk for injury and the necessity of wearing protective eyewear to avoid an ocular injury in the future. My preference is to use a femtosecond laser to perform geometric cuts. This approach has the advantages of excellent graft–host apposition without focal areas of steps from graft slippage as well as increased wound strength.3 In addition, the femtosecond laser generates a strong wound-healing response with good fibrosis, which further improves the biomechanical strength of the graft–host wound. My favored configuration is a modified mushroom profile that has an undercut anteriorly that slots

into the host cornea. The eye has a previous 9.5 mm flap and currently has epithelial ingrowth; thus, it is likely that the periphery of the anterior portion of the mushroom profile (8.0 to 8.6 mm) will cross the area of epithelial ingrowth above and below. In view of this, it would be best in preparation for surgery to remove both areas of epithelial ingrowth and suture the flap at the 2 locations. Sutures can be removed at 3 to 4 weeks, and graft surgery can proceed soon after. During surgery, the surgeon will have to take great care to avoid dislodging the residual corneal flap. Femtosecond laser DALK would involve mounting the donor graft on an air-filled artificial chamber. The laser would be programmed to oversize the anterior cut by 0.2 mm (ie, 8.2 to 8.7 mm) to avoid a large hyperopic result from excessive corneal flattening postoperatively. Once the donor cornea is fashioned, the recipient would be geometrically trephined with the femtosecond laser using the dimensions shown in a video (available at http://ascrs2013.conferencefilms. com/acover.wcs?entryid=100162). The prepared recipient would then be moved to the operating room, where the host would be dissected using a Lester pusher (Duckworth and Kent). A big-bubble technique4 would be used to separate Descemet membrane from the corneal stroma, the host cornea removed, and donor button sutured after removal of Descemet membrane. Sheraz Daya, FACP, FACS, FRCS(Ed), FRCOphth London, United Kingdom

REFERENCES 1. Naoumidi I, Papadaki T, Zacharopoulos I, Siganos C, Pallikaris I. Epithelial ingrowth after laser in situ keratomileusis: a histopathologic study in human corneas. Arch Ophthalmol 2003; 121:950– 955. Available at: http://archopht.jamanetwork.com/data/Journals/ OPHTH/9909/ECS20262.pdf. Accessed July 16, 2014 2. Rojas MC, Lumba JD, Manche EE. Treatment of epithelial ingrowth after laser in situ keratomileusis with mechanical debridement and flap suturing. Arch Ophthalmol 2004; 122:997–1001. Available at: http://archopht.jamanetwork.com/ data/Journals/OPHTH/9926/ECS30159.pdf. Accessed July 16, 2014 3. Steinert RF, Ignacio TS, Sarayba MA. “Top hat”-shaped penetrating keratoplasty using the femtosecond laser. Am J Ophthalmol 2007; 143:689–691 4. Anwar M, Teichmann KD. Big-bubble technique to bare Descemet’s membrane in anterior lamellar keratoplasty. J Cataract Refract Surg 2002; 28:398–403

- This patient's visual acuity is more limited by residual astigmatism than by stromal opacity. I would emphasize the necessity of another trial with gaspermeable, full scleral lenses and tell the patient that this solution would bring him optimum visual recovery.

J CATARACT REFRACT SURG - VOL 40, SEPTEMBER 2014

Refractive Surgical Question: September consultation #1.

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