Mahmoud A. Khaimi, MD J. Matthew Rouse, MD Rhea Siatkowski, MD Dean McGee Eye Institute

1. Visualization of Epithelial Downgrowth of Inferior Angle, Iris, and Corneal Endothelium With Means of Endolaser Probe Mahmoud A. Khaimi, MD J. Matthew Rouse, MD Rhea Siatkowski, MD Dean McGee Eye Institute Oklahoma City, Oklahoma The authors have no financial interest in this subject matter.

2. Purpose • To evaluate a unique approach to visualize and treat epithelial downgrowth using ocular endoscopic technology in a 64 year old post-penetrating keratoplasty patient who developed signs of this surgical complication.

3. Introduction • Epithelial downgrowth is a sight and eye-threatening complication that may occur after ocular surgery or trauma. • Clinical prevalence has been reported at 0.09-0.12%1 • Risk factors include prolonged inflammation, wound dehiscence, delayed wound closure and Descemet’s membrane tears. • Pathologically, the downgrowth consists of non-keratinized, stratified squamous epithelium with avascular subepithelial connective tissue1

4. Introduction • Epithelial downgrowth should be treated as it can have devastating effects on underlying tissues with development of secondary glaucoma, decreased vision, inflammation and destruction of ocular tissue. Greater than 95% of untreated cases result in enucleation.2 • Multiple treatment methods have been attempted with varying success. En bloc excision of areas involved with epithelial downgrowth has been associated with variable rates of recurrence and complications.3 • Transcorneal cryotherapy has been a successful adjunct, but can cause heat damage to adjacent tissue4 • There has been limited report of endoscopic treatment of epithelial downgrowth with diode laser.3

5. Case Study • A 63 year old male underwent uneventful penetrating keratoplasty (PK) of his left eye in November of 2009 after developing a corneal ulcer in his prior graft. He had also previously undergone pars plana vitrectomy, anterior chamber lens placement and tube shunt placement in the eye. • Six weeks after the PK, he presented with a membrane over the corneal endothelium inferiorly. This membrane was consistent with the appearance of epithelial downgrowth and progressed towards the center of the cornea over the next week.

6. Presentation 6 weeks after PK A distinct line of endothelial membrane can be noted on the corneal button.

7. Extending line of epithelial downgrowth Extension of Epithelial Downgrowth The line of endothelial membrane extended in the first week after presentation. This prompted the decision to return to surgery for treatment of the presumed epithelial downgrowth.

8. Surgical Technique • Intraoperatively, a corneal graft suture was removed and Healon viscoelastic was placed into the anterior chamber. • The endoscopic handpiece of the diode photocoagulation laser was used to apply laser to the endothelial surface, iris surface, inferior chamber angle and location of the epithelial downgrowth through the graft-host junction. Whitening was noticed throughout the areas covered with membrane. A whitish membrane was then peeled off of the iris surface and pupillary margin. • The laser was also used underneath the iris and around the pupillary margin. • The borders of the downgrowth were noted to be from approximately 3 o’clock to 7 o’clock

9. Surgical Technique • After extensive use of the endophotocoagulation handpiece, a cryotherapy probe was applied transclerally at the limbus in the clock hours of 7 to 9 o’clock. • The affected corneal button and the anterior chamber intraocular lens were removed. Anterior vitrectomy was performed. A new PK corneal button was then sewn to the eye. • Intraocular injection of Decadron as well as subconjunctival injections of Fortaz and Kenalog were given at the end of the case.

10. Results • Pathologic analysis of the removed corneal button revealed a focal area of nonkeratinized stratified squamous epithelium on the posterior surface of Descemet’s membrane which is consistent with the diagnosis of epithelial downgrowth. • Eleven months after surgery, there has been no sign of recurrence in the operative eye. • Best corrected visual acuity is 20/150. This vision is limited due to cystoid macular edema in the eye.

11. Discussion • Epithelial downgrowth is an eye-threatening complication in which treatment is difficult. • Various excisional and laser treatments have been used in treatment of this complication. • Endoscopic photocoagulation is a safe and effective tool to be used in treatment of epithelial downgrowth. It may prove even more useful in settings where visualization is compromised through the cornea or downgrowth has occurred in locations where other treatments may not be able to reach.

12. References 1. Yanoff M, Sassani JW. Ocular Pathology. 6th edition China: Elsevier, 2009. • Vargas LG, Vroman DT, Solomon KD, et al. Epithelial downgrowth after clear cornea phacoemulsifcation: report of two cases and review of the literature. Ophthalmology. 2002: 109: 2331-2335. • Jadav et al. Endoscopic Photocoagulation in the Management of Epithelial Downgrowth. Cornea. 2008: 27: 5 : 601-604 • Zavala EY, Binder PS. The pathologic findings of epithelial ingrowth. Arch Ophthalmol. 1980:98: 2007-2014.