LETTERS TO THE EDITOR Annular Herpetic Keratitis After Intracorneal Ring Segment Implantation To the Editors: We present a 26-year-old man who underwent an intracorneal ring segment (ICRS) implantation for treatment of grade 2 keratoconus in his left eye by performing mechanical corneal dissec- tion. 1 The incision was performed at the 7-o’clock position, and the ICRS was placed inferonasally. His ophthalmological history was only remarkable for kerato- conus treated with gas-permeable contact lenses and a history of herpetic keratitis 5 years previous to ICRS implantation. Five days after the surgery, the patient presented with intense left eye pain. On examination, an annular den- dritic ulcer was observed (Fig. 1). The epithelial defect was just above the course of the stromal tunnel created at the time of ring implantation. Considering his medical history and the dendritic ulcer, a diagnosis of herpetic keratitis was made. Treatment was started immediately with topical acyclovir 5 times per day and artificial tears 6 times per day for 1 week. Three days after the treatment was completed, the patient reported no pain, and on exploration, there was no sign of herpetic ulcer. ICRS implantation has been reported to be a safe surgical technique for the treatment of keratoconus. 2 There have been different reports describing bacterial infectious keratitis after ICRS implantation. 3 To the best of our knowledge, this is the first case describing herpetic keratitis after ICRS implantation. Given the experience we have had with this case, in the future, we propose that herpes prophylaxis be considered before ICRS implantation in eyes with a history of herpetic keratitis. Early recognition and prompt treatment of the infection may be required to prevent serious sight-threatening complications of ICRS implantation. Financial disclosures/conflicts of inter- est: None reported. Omar Rayward, MD Pedro Arriola-Villalobos, MD Ricardo Cuin ˜ a-Sardin ˜a, MD David Diaz-Valle, PhD Jose Manuel Ben´ ıtez-Del-Castillo, PhD Julia ´n Garc´ ıa-Feijoo, PhD Hospital Cl´ ınico San Carlos, Madrid, Spain REFERENCES 1. Ertan A, Colin J. Intracorneal rings for kerato- conus and keratectasia. J Cataract Refract Surg. 2007;33:1303–1314. 2. Colin J, Cochener B, Savary G, et al. INTACS inserts for treating keratoconus: one-year results. Ophthalmology . 2001;108:1409–1414. 3. Hofling-Lima AL, Branco BC, Romano AC, et al. Corneal infections after implantation of intracorneal ring segments. Cornea. 2004;23: 547–549. Sodium Hyaluronate Gel as Mitomycin C Vehicle to Reduce Potential Endothelial Toxicity in Pterygium Surgery To the Editors: We read with interest the article ‘‘Endothelial cell loss during pterygium surgery: importance of timing of mito- mycin C application’’ by Avisar et al. 1 The authors reported no endothelial cell loss if mitomycin C (MMC) had been applied before excision of the head of pterygium. In using a solution form of MMC, it is difficult to avoid any inadvertent spillage onto the ocular surface. 2 In addition to endothelial damage, MMC is also harm- ful to the sclera and ciliary body. 3 To minimize the noxious effects of MMC on ocular tissues, we conducted a prospective randomized study to examine the safety and benefits of using a gel form of MMC in pterygium surgery. Instead of the conventional MMC solution soaked in sponges, a MMC gel was prepared by mixing sodium hyaluronate gel and trypan blue. Fifty consecutive patients with pri- mary pterygium were randomly assigned to the gel group or solution group. Endothelial images were acquired at the center of the cornea with a noncontact specular micro- scope before the surgery and at 1 week, 1 month, 3 months, and 6 months after the surgery. In the gel group, the postoperative mean endothelial cell density only de- creased by 3.6% at 1 month, without any significant changes at 1 week, 3 months, and 6 months. In addition, there was no difference in pterygium recurrence be- tween the 2 groups. Because the visibility of sodium hyaluronate gel carrying MMC is en- hanced by the presence of trypan blue, any unwanted direct contact with the cornea and ocular surface is easily avoided. 4 Because the molecular weight of sodium hyaluronate is more than 800 kDa and the corneal and scleral perme- ability 5 is dependent on solute size, solubility, and molecular conformation, diffusion through the cornea and sclera should be minimized. FIGURE 1. Annular herpetic keratitis just above the stromal tunnel created at ICRS implantation surgery. 1286 | www.corneajrnl.com Cornea  Volume 30, Number 11, November 2011