Learning from the past: Mitomycin C use in trabeculectomy and its application in bleb-forming minimally invasive glaucoma surgery.

Trabeculectomy has been performed since the mid-1960s and remains the gold standard for glaucoma surgery. Newer surgical options have evolved, collectively referred to as minimally invasive glaucoma surgeries. Despite producing large intraocular pressure decreases, full-thickness procedures into the subconjunctival space may be limited by fibrosis. Mitomycin C (MMC) and 5-fluorouracil have been in use with trabeculectomy with good evidence of significantly increased success at the cost, however, of an increased risk of complications. Off-label MMC application can be found in almost all clinical trials, including in combination with minimally invasive glaucoma surgeries. We explore current evidence for MMC use in trabeculectomy and how this may differ for minimally invasive glaucoma surgery devices and analyze the range of agents and doses that are used. Although we found that most studies could not show any correlation between MMC dosage and the surgical outcome, the success rates with the Xen® microshunt seemed to be higher when using 20 mcg of MMC than when using 10 mcg. Certain important methodological considerations make this hard to confirm definitively, and other factors such as placement of the device may play a more substantial role. For the PreserFlo® microshunt, preliminary data suggest higher success rates with higher MMC dosage at the cost of higher device-related adverse events and reoperations. Although the ideal dose still needs to be established, it seems very likely that MMC provides significant improvement in outcomes in bleb-forming minimally invasive glaucoma procedures.

Glaucoma Surgery with Soaked Sponges with Mitomycin C vs Sub-Tenon Injection: Short-term Outcomes.

AIM: The aim of this study is to compare the outcomes, success rates, complications, and number of interventions of the trabeculectomy surgery with mitomycin C (MMC) in two different techniques: conventional soaked sponges and sub-Tenon injection. MATERIALS AND METHODS: An observational retrospective study was performed with 79 eyes of 64 participants who underwent a glaucoma surgery with MMC. The conventional sponge soaked with MMC 0.03% for 3 minutes over the scleral flap (group I) and the subtenon injection of 0.1 mL of MMC 0.03% (group II) techniques were used to deliver the MMC. The data collected were patient demographics, preoperative intraocular pressure (IOP), central corneal thickness (CCT), number of pre- and postoperative ocular hypotensive drugs, postoperative complications, number of interventions, and need of further glaucoma surgery. RESULTS: Seventy-nine eyes were divided into two: 39 eyes (49.37%) in group I and 40 eyes (50.63%) in group II. Trabeculectomy was performed in 53.17% and phacotrabeculectomy in 46.83%. The IOP decreased from 18.0 ± 11.0 mm Hg at the baseline to 10.0 ± 3.0 mm Hg at the last visit in group I and, in group II, from 16.0 ± 10.0-13.0 ± 6.0 mm Hg (median ± ID), p < 0.001. There were no significant differences between the groups regarding demographics, median follow-up, IOP in baseline, CCT, drugs reduction, success criteria adopted, postsurgical interventions, surgical complications, and need for new procedures (p > 0.05). CONCLUSION: Sub-Tenon injection of MMC is a safe and as effective as the conventional soaked sponge method in trabeculectomies. This method reduces surgical time and sponge-related risks with equivalent surgical efficacy. CLINICAL SIGNIFICANCE: As trabeculectomy is still the most common surgical procedure to reduce IOP and scar formation is one of the main causes of surgical failure, it is important to develop surgical techniques to improve its outcomes. HOW TO CITE THIS ARTICLE: Guimarães MEV, de Pádua Soares Bezerra B, et al. Glaucoma Surgery with Soaked Sponges with Mitomycin C vs Sub-Tenon Injection: Short-term Outcomes. J Curr Glaucoma Pract 2019;13(2):50-54.

Intraocular pressure measurement after corneal transplantation.

Measurement of intraocular pressure is an integral part of a comprehensive ocular examination, especially after a surgical intervention that can affect aqueous humor flow dynamics. Most of the intraocular pressure measurement devices are designed for "normal" corneas and may not be accurate in eyes after corneal transplantation where there is altered corneal morphology. Raised intraocular pressure and glaucoma are known postoperative complications after transplantation, and therefore, accurate intraocular pressure measurement is essential. We review the effect of abnormal corneal curvature, corneal thickness, and different biomechanical properties in the context of corneal transplantation on intraocular pressure measurement using a number of devices.