We appreciate Drs Basu and Swangwan for their interest in our recently published article, “Efficacy and Safety of Conductive Keratoplasty in Keratoconus,” a clinical trial report for a novel treatment for advanced keratoconus.
We originally began topography-guided conductive keratoplasty as a preparative regimen for corneal transplantations, because correcting asymmetry of the cornea before the transplantation may reduce the postoperative astigmatism. However, some patients obtained much better visual acuity than expected immediately after the conductive keratoplasty procedure. They were satisfied with the results and postponed the corneal implant. Therefore, we began this treatment as an independent procedure for reshaping the cornea, conducting the clinical investigation.
We agree that complications should be examined carefully. We believe that the important complications are infection and corneal perforation for the short term and visual disturbance resulting from stromal scar and regression for the long term. Fortunately, we did not observe any short-term complications in the present cases. However, we showed that the average value of uncorrected visual acuity, best spectacle-corrected visual acuity, manifest refraction, and corneal curvature were improved significantly immediately after the surgery had regressed after 3 months. However, about one half of the enrolled patients were able to use hard contact lenses, even after the regression occurred and the corneal shape could not retain the best configuration. Considering that all of them previously had planned to undergo corneal transplantation because of contact lens intolerance, the topography-guided conductive keratoplasty was determined to be effective as a means to avoid or at least postpone transplantation. Retaining the corneal configuration after surgery is the next challenge to be solved, and one that we currently are investigating.
Measuring accurate intraocular pressure and corneal endothelial cell counts is sometimes difficult in cases with advanced keratoconus, especially when the corneal epithelium is affected or the cornea reveals stromal scars. From our experience, it is not unusual that measuring intraocular pressure or corneal endothelial cell counts is impossible even when the corneal topography is assessable, and vice versa. Neither elevation of intraocular pressure nor endothelial loss that may cause irreversible loss of visual function were ignored; however, both have not been reported so far.
Some clinicians reported similar procedures using conductive keratoplasty for keratoconus eyes. However, pronounced propensity for regression was not reported probably because of the limited number of operated eyes and short duration of postoperative follow-up. In addition, we found that the corneal reshaping was not successful in the patients with resolved hydrops or with stromal scars. Those were our first findings after we conducted the present investigation. We believe that reporting all of both positive and negative results is necessary and contributes to the development of the procedure. We hope that more adequate inclusion criteria could be determined, and modification of this procedure will be carried out to reshape and retain the corneal configuration of advanced keratoconus assuredly by further investigation with a larger number of eyes and longer follow-up period.