The authors would like to thank Dr. Scharioth for his useful and expert opinion. Pre-Descemet hematoma is a relatively rare intraoperative complication of canaloplasty.1 The mechanism of Descemet membrane detachment during procedures on Schlemm canal is not entirely clear, and both the surgical technique and anatomic factors might contribute to this complication. The classic canaloplasty surgical technique does not allow control of the pressure inside Schlemm canal during the viscodilation, which is presumed to cause Descemet membrane detachment.2–4 Other authors have described it as a complication of canaloplasty and viscocanalostomy.5–9 Nonetheless, pre-Descemet hematoma occupying the visual axis is an extremely rare complication of canaloplasty.1 Our team is also very experienced in glaucoma surgery. We have performed approximately 8000 nonpenetrating as well as 400 canaloplasty procedures, and such a complication was observed in 1 patient only.
In our opinion, the way of handling pre-Descemet hematoma was accurate. Only early hematoma evacuation done during the primary procedure, which was presented in the article as a new surgical technique, made it possible to achieve good visual acuity immediately after the surgical procedure. Thanks to this method, waiting for long-lasting resolution of the hematoma was avoided. Moreover, the outcome of a wait-and-see strategy suggested in Dr. Scharioth’s letter would be uncertain; in the worse-case scenario, it could lead to permanent vision impairment. There was no need to perform a second surgery, which seems to be very comfortable for both the patient and surgeon. This method was inspired from the teams’ experience in performing lamellar corneal transplantation.
Dr. Scharioth pointed out that classic canaloplasty using the iTrack flexible microcatheter might carry a higher risk for Descemet membrane detachment because one of its elements is viscodilation of Schlemm canal in comparison to modified canaloplasty using the Glaucolight, in which viscodilation of Schlemm canal is not performed. It should be emphasized that there is not a sufficient number of reports in the literature on this modified method; no clinical studies published describe different aspects of this procedure. For this reason, it is difficult to agree with Dr. Scharioth’s opinion of a favorable safety profile for modified canaloplasty.
Large prospective randomized clinical trials comparing the iTrack and Glaucolight devices should be planned to assess the differences between these 2 surgical methods of canaloplasty in regard to IOP, the need for antiglaucoma medication, and the rates of intraoperative and postoperative complications. A study comparing those 2 methods is being performed at our clinical center. We hope that we will be able to present the outcomes in the near future.
In our opinion, canaloplasty assisted with the Glaucolight device requires a longer learning curve and seems to be more challenging than with the iTrack device because the catheter is thinner and more flexible. Use of the Glaucolight might result in technical difficulties during intubation and might be more traumatic to Schlemm canal. However, this is only the experience of our team and cannot be verified because no scientific papers on the subject are available.
1. Jaramillo A, Foreman J, Ayyala RS. Descemet membrane detachment after canaloplasty: incidence and management. J Glaucoma
2. Palmiero P-M, Aktas Z, Lee O, Tello C, Sbeity Z. Bilateral Descemet’s membrane detachment after canaloplasty. J Cataract Refract Surg
3. Smit BA, Johnstone MA. Effects of viscoelastic injection into Schlemm’s canal in primate and human eyes; potential relevance to viscocanalostomy. Ophthalmology
4. Wild GJ, Kent AR, Peng Q. Dilation of Schlemm’s canal in viscocanalostomy: comparison of 2 viscoelastic substances. J Cataract Refract Surg
5. Stegmann R, Pienaar A, Miller D. Viscocanalostomy for open-angle glaucoma in black African patients. J Cataract Refract Surg
6. Robert M-C, Harasymowycz P. Hemorrhagic Descemet detachment after combined canaloplasty and cataract surgery. Cornea
7. Freiberg FJ, Parente Salgado J, Grehn F, Klink T. Intracorneal hematoma after canaloplasty and clear cornea phacoemulsification: surgical management. Eur J Ophthalmol
8. Gismondi M, Brusini P. Intracorneal hematoma after canaloplasty in glaucoma. Cornea
9. Fujimoto H, Mizoguchi T, Kuroda S, Nagata M. Intracorneal hematoma with Descemet membrane detachment after viscocanalostomy. Am J Ophthalmol