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