1. Surgically removed Epithelial membrane ingrowth after clear cornea incision cataract surgery Jae-Wook Jung, M.D, Sung-Dong Chang, M.D, Ph.D, Department of Ophthalmology, School of Medicine, Dongsan Medical Center, Keimyung University, Daegu, Korea Authors have no financial interest

2. INTRODUCTIO N Epithelial membrane ingrowth is one of the rare complications where the corneal or conjunctival epithelium invades the anterior chamber due to the ocular trauma during the procedures of ECCE, ICCE, glaucoma filtration surgery and corneal transplantation. Its prevalence has been reported to be approximately 0.06-0.11% in patients who underwent intraocular surgery. Cases in which the corneal and conjunctival ingrowth can occur include the intraocular surgery, an incomplete or delayed wound healing, wound fistula, iris incarceration and suture site leakage. With the recent advancement of cataract surgery, the environment that can provide the trauma for cornea and eye ball during the cataract surgery has been diminished. Various treatment regimens include irradiation, cycloablation, Argon laser photocoagulation, surgical removal and using of antimetabolite. But these methods have been reported to have a high failure rate and they can damage the eye ball itself. We experienced a case of epithelial membrane ingrowth which was developed at the site of clear corneal incision following the cataract surgery, for which we successfully treated surgically without complications.

3. A 55-year-old man visited us with a chief complaint of a 6-month-history of gradually progressing visual disturbance in the left eye. The patient underwent cataract surgery using sutureless phacoemulsification with clear corneal incision four years ago. At the time of admission, the visual acuity was 20/25 and the intraocular pressure was 13mmHg. A slit lamp microscopy showed that the epithelial membrane grew from 12:30 to 6:00 O/C at an approximately 4.5mm width to the center along the incision area in retrocorneal surface. The anterior chamber angle was also invaded. ectropion uvea was also concurrently present (Figure A). In the superior area of the clear corneal incision site, there were findings which were suspected to be the fistula (Figure B). CASE A A B A

4. About 1.5mm sized nasal corneal incision was made. Pressed and grinded, flat, blunt modified spatula was used to carefully dissect retrocorneal membrane and endothelium.(Figure C) Through the paracentesis, viscoelastics were gradually infused by a 27G anterior chamber needle and thereby the epithelial membrane was dissected up to the anterior chamber angle. (Figure D) CASE B C D

5. The area with a severe adhesion was delaminated with using of micro-scissior. Using forceps, the periphery of epithelial membrane was carefully retracted. Meanwhile, the epithelial membrane was isolated from the anterior chamber angle (Figure E). After the fistula was confirmed at the site of corneal incision, the epithelium lining the fistula was curretaged from inside of the anterior chamber to outside of the cornea. Then, the suture was tightly performed (Figure F). CASE E F

6. Next day on surgery, the cornea was edematous. The visual acuity in the left eye was 20/60 and the intraocular pressure was 14mmHg.(Figure G) 1 month after surgery, the focally detached Descemet ’ s membrane was observed in the superior area to the site of corneal incision.(Figure H) The visual acuity in the left eye was 20/30, the BCVA was 20/20 and the intraocular pressure was 11mmHg. In the center, the endothelial cell density was 2433 cells/mm 2. CASE G H

7. 6 months after surgery, the visual acuity in the left eye was 20/20. In the center, the endothelial cell density was 2132cell/mm 2 and intraocular pressure was 10mmHg. Meanwhile, there were no findings which were suggestive of the recurrence and complications.(Figure I) Surgically removed tissues had histopathological findings of nonkeratinized, stratified squamous epithelial cells(Figure J), which were confirmed to have an epithelial ingrowth. CASE I J

8. DICUSSION It has been reported that such surgical treatments as iridectomy, cycloablation and en bloc resection caused a higher recurrence rate, the disturbance of corneal function, corneal transplantation, vitreal bleeding, glaucoma and enucleation. In the surgical treatment, Naumann GOH and Rummelt V performed enblock excision and anterior vitrectomy including the dissection of cornea, sclera and iris in cases of cystic formation and diffuse sheet-like epithelial proliferation. According to them, the most severe postsurgical complication was corneal endothelial decompensation. In addition, there were secondary complications including glaucoma and globe atrophy. According to some authors, such medical teatments as the application of potassum chloride, 5-fluorouracil and mitomycin-C, steroid and antibiotics in the treatment of epithelial ingrowth could cause such complications as glaucoma. In addition, other treatment methods include transcorneal cryotherapy. It has been reported that due to the cryoablation effect, however, it can cause a damage to the adjacent tissue. Argon laser photocoagulation is less invasive than cryotherapy and it can reduce the occurrence of trauma and inflammation for the adjacent tissue. Moreover, using of photocoagulation in the retrocornea would cause the corneal opacity due to heat injury in the corneal endothelium.

9. DICUSSION The epithelial membrane ingrowth, which occurred following the implantation of IOL after sutureless phacoemulsification through scleral tunnel incision, was first reported by Holliday JN in 1993. Argon laser therapy was performed for iris. The treatment was performed with a penetrating sclerokeratoplasty. Following the removal of corneoscleral button, the iridectomy was performed and a cryoablation was synchronously performed. The epithelial membrane ingrowth which was developed following sutureless corneal incision phacoemulsification was first reported by Knauf HP in 1997. Its pattern was a cystic epithelial membrane ingrowth. The lesions were removed by en bloc resection as well as iridectomy including the dissection of cornea, sclera and iris with a corneal incision. Thereafter, a sheet form of epithelial membrane ingrowth was reported by BL.Lee et al. They reported it is possible that there was an unappreciated gaping of an unsutured corneal wound that contributed to the development of the abnormality. Valgas LG. et al. treated the epithelial membrane ingrowth with the surgical technique of an eccentric corneal and scleral transplantation

10. In regard to the epithelial membrane ingrowth which was developed following the cataract surgery, the fistula provided the route for the ingrowth of epithelial membrane. Edward Maumenee et al. reported that the fistula was formed in the anterior chamber in 19 cases of a total of 40 cases in association with the ingrowth of epithelial membrane following cataract surgery. Schaeffer AR. reported that the route for fistula formation was created at the site of incision wound, where the capsular remnant was incarcerated, in association with the epithelial membrane ingrowth following ECCE. Besides, Soong HK et al. reported that the fistula could be formed due to a leakage which was generated via a scleral incision at the site of corneal limb. As described herein, to make sure that the epithelial membrane ingrowth should be persistent, the cornea and epithelium must provide the stem cells everlastingly. This must be accompanied by the formation of fistula which provides the tract. Cell-to-cell interaction and other various growth factors can persist the epithelial membrane ingrowth. The normal uninflammed arqueous can maintain the epithelial membrane, but it cannot proliferate it. In accordance with the experimental models, the background of epithelial ingrowth must have wick of conunctival tissue within the surgical margin of a hypotonus, imflamed eye, or the use of carcinogens. DICUSSION

11. Conclusion Accordingly, the simple removal of epithelial membrane for the treatment of epithelial ingrowth is insignificant. The fistula, providing the route for proliferation, and its lining epithelium must also be removed. In the current case, through a clear corneal incision, the epithelial membrane ingrowth into the retrocornea, iris and anterior chamber angle was dissected. Thus, the lesions were surgically removed and removal of fistula which was intraoperatively identified had to be also performed. In diagnosis of epithelial ingrowth, argon laser photocoagulation was not performed. This is because the dissection would be difficult due to the occurrence of the adhesion of epithelial membrane and iris following argon laser photocoagulation. In our case, a diagnosis was established based on histopathologic findings of the excised specimen. There were no postoperative complications or findings which were suggestive of the recurrence. Six months postoperatively, the visual acuity was 20/20.

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