I thank Drs Gupta and Gupta for their interest in our article. We designed our study based on the invaluable previous works by Donnenfeld and associates and Ucakhan and associates, and modified the study protocol to address the safety and efficacy of newly introduced methods in pterygium surgery in a prospective, randomized, comparative study. Noticeably, there was no previously published work on comparison of preoperative subpterygeal mitomycin C (MMC) injection and conjunctival grafting after bare scleral excision for pterygium management. I agree with Drs Gupta and Gupta that the preoperative subpterygeal MMC injection could be somewhat uncomfortable for patients because it is a 2-stage procedure. However, regarding the office-based nature of the first step, this would not increase patients cost considerably or take significant time. Conjunctival hypovascularity and whitening at the site of surgery, although occurring in a minority, are certainly unpleasant for some patients; but considering the reduced recurrence rate and faster recovery after surgery, this could be acceptable.

The role of the precise site of MMC injection should be addressed in future studies; however, based on the current level of evidence, we hypothesized subpterygeal injection of MMC as the most favorable route with the fewest side effects. Avisar and associates highlighted the importance of timing of MMC application during pterygium surgery for endothelial protection. Noticeably, in their study MMC application before removal of the pterygium head was associated with less endothelial cell loss, and the authors attributed this finding to the integrity of the corneal epithelium. I believe that subpterygeal MMC injection similarly would protect corneal endothelium against the toxic effects of MMC and that this could not be compared with application of MMC to the bare sclera during the conventional bare scleral pterygium excision technique.

We included patients with a wide range of ages in the study to address different possible complications of surgical procedures. Obviously, recurrence would be more common in younger patients; however, complications such as scleral necrosis and corneal toxicity intuitively would be more common in older patients. Other investigators included a similarly wide range of patients in clinical trials of pterygium management.

Drs Gupta and Gupta’s suggestion to perform a rotational conjunctival flap in patients with preoperative subpterygeal MMC injection is an interesting options for designing future researches. However, there are well-established cases of conjunctival autograft failure and pterygium recurrence in patients with previous exposure to MMC. Hence, we believe that adding a rotational conjunctival flap to the simple bare scleral excision in the preoperative MMC group may be problematic and should be done cautiously.

As stressed previously, I believe that applying MMC to the subpterygeal area is not exactly the same as MMC application to the bare sclera. Avisar and associates’ work on the importance of MMC timing during pterygium surgery on endothelial cell loss elucidated the importance of integrity of corneal epithelium as a potential barrier to the toxic effects of MMC on endothelium. I believe that subpterygeal MMC injection before manipulation of the corneal surface similarly would protect corneal endothelium. This hypothetical benefit should be evaluated in the future studies. Performing clinical trials for comparing these two techniques for pterygium surgery in a larger cohort of patients with longer follow-up periods and incorporating endothelial cell density and morphologic features along with intraocular pressure in data analysis are highly desirable.

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Jan 16, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Reply

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