Endothelial Cell Loss May Accompany Glaucoma Procedures

Glaucoma and various treatments for the disease can significantly affect endothelial cell loss (ECL) in the cornea. Researchers reviewed the impacts of various treatments in an article recently published in Journal of Glaucoma.¹

Researchers have found that eyes with glaucoma have lower endothelial corneal density (ECD) than healthy eyes. Eyes with primary open-angle glaucoma (POAG), angle-closure glaucoma and pseudoexfoliation glaucoma, which all involve increased intraocular pressure (IOP), are prone to reduced ECD.

IOP-lowering medications such as prostaglandin F2 analogs, beta-blockers, carbonic anhydrase inhibitors (CAIs), alpha-adrenergic agonists, miotics, rho kinase inhibitors, nitric oxide, and combinations of medication classes have shown minimal impacts on ECD and corneal endothelial cells (CEC). The report does not identify any studies that showed adverse effects of the medications on ECD or CEC.

Procedures that do not involve implantation of a device typically have little effect on ECD, while procedures that involve a permanent implant tend to have greater effects on ECD, according to the report. It partially attributes this to improper device placement that is too close to the corneal endothelial surface. The report provides research on specific devices and their relationship to ECD.

Laser peripheral iridotomy (LPI) with argon, Nd:YAG, or both have shown “modest effects” on ECD, the study says. While many studies on argon LPI have shown no impact on ECD or CEC through 1 year of follow-up, 1 study reported ECL of 8% 1 month later and another reported increased CEC size 3 months later.^2,3 LPI with Nd:YAG laser have shown mixed results, with 1 study showing no significant ECL through 6 months of follow-up and a 2-year retrospective analysis reporting significantly less ECL following phacoemulsification than combined argon-Nd:YAG LPI both 1 and 2 years after treatment.

Patients with bilateral primary chronic angle-open glaucoma had higher ECL following argon LPI (8%) compared with those who received Nd:YAG LPIs (0%) in 1 study (P <.01).

Multiple studies have reported no effects of argon laser trabeculoplasty (ALT) on ECD through 1 year of follow-up, but 1 study reported significantly increased CEC 6 months after the procedure.

The surgical procedure of phacoemulsification showed ECL of 10% within 3 months in the COMPASS and COMPASS XT supraciliary microstent study. Eyes with anatomically narrow angles that underwent phacoemulsification experienced 14.5% ECL (P <.001) within 3 months in another study.

Some studies have shown that trabeculectomies with mitomycin C (MMC) have greater ECL than those without MMC and that the ECL tends to occur within the first 3 months. Ophthalmologists can reduce IOP and CEC damage by using inflating or maintaining the anterior chamber maintainer during surgery. At 12 months, trabeculectomy tends to have greater ECL than deep sclerectomy and less ECL than Ahmed valve implantation.

“In general, concerns for CEC health should be part of the decision-making process when planning glaucoma surgery for lowering IOP, with added caution in case of planned device implantation in eyes with preexisting ECL and low ECD counts at high risk for corneal endothelial decompensation,” the authors wrote.

Disclosure: Some study authors declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.  

Reference

Realini T, Gupta PK, Radcliffe NM, et al. The effects of glaucoma and glaucoma therapies on corneal endothelial cell density. J Glaucoma. 2021;30(3):209-218. doi:10.1097/IJG.0000000000001722