Corneal Endothelial Cell Density Loss after Glaucoma Surgery Alone or in Combination with Cataract Surgery: A Systematic Review and Meta-analysis

Topic: Corneal endothelial cell density (ECD) loss after glaucoma surgery with or without cataract surgery.

Clinical relevance: Corneal ECD loss may occur as the result of intraoperative surgical trauma in glaucoma surgery or postoperatively with chronic endothelial cell trauma or irritation.

Methods: Glaucoma filtration surgery or microinvasive glaucoma surgery (MIGS) in participants with ocular hypertension, primary and secondary open-angle glaucoma, normal-tension glaucoma, and angle-closure glaucoma were included. Electronic databases searched in December 2021 included MEDLINE, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, the International Prospective Register of Systematic Reviews, Food and Drug Administration (FDA) Premarket Approval, and FDA 510(k).

Results: A total of 39 studies were included in quantitative synthesis. Twelve months after suprachoroidal MIGS, mean ECD loss was 282 cells/mm² (95% confidence interval [CI], 220-345; P < 0.00001; chi-square = 0.06; I² = 0%; 2 studies; very low certainty). Mean ECD loss after Schlemm's canal implantable devices was 338 cells/mm² (95% CI, 185-491; P < 0.0001; chi-square = 0.08; I² = 0%; 2 studies; low certainty) at 12 months. Mean ECD loss was 64 cells/mm² (95% CI, 21-107; P = 0.004; chi-square = 4.55; I² = 0%; 6 studies; low certainty) after Schlemm's canal procedures (without implantable devices) at 12 months. At 12 months, the mean ECD loss after trabeculectomy was 33 cells/mm² (95% CI, -38 to 105, P = 0.36, chi-square = 1.17; I² = 0%; moderate certainty). At 12 months, mean ECD loss was 121 cells/mm² (95% CI, 53-189; P = 0.0005; chi-square = 3.00; I² = 0%; 5 studies; low certainty) after Express (Alcon) implantation. When compared with the control fellow eye, aqueous shunt surgery reduced ECD by 5.75% (95% CI, -0.93 to 12.43; P = 0.09, chi-square = 1.32; I² = 0%; low certainty) and 8.11% ECD loss (95% CI, 0.06-16.16 P = 0.05; chi-square = 1.93; I² = 48%) at 12 and 24 months, respectively.

Conclusions: Overall, there is low certainty evidence to suggest that glaucoma surgery involving long-term implants has a greater extent of ECD loss than glaucoma filtration surgeries without the use of implants. The results of this review support follow-up beyond 36 months to assess ECD loss and corneal decompensation after implantation of glaucoma drainage implants.