Nonpenetrating Deep Sclerectomy versus Conventional Surgery in Primary Congenital Glaucoma: a Systematic Review and Meta-analysis

Primary congenital glaucoma (PCG) is a leading cause of irreversible childhood blindness, with elevated prevalence in consanguineous populations of the Middle East and Central Asia. Nonpenetrating deep sclerectomy (NPDS) is theoretically safer than conventional penetrating surgery, yet comparative evidence lacks systematic synthesis. We systematically searched seven databases through December 2025. Eligible studies compared NPDS with conventional surgery in children with PCG aged under 4 years with ≥ 6 months follow-up. Two reviewers independently screened and extracted data; risk of bias was assessed with ROBINS-I and RoB 2.0. A random-effects meta-analysis REML with Hartung–Knapp–Sidik–Jonkman (HKSJ) correction was performed. Five studies seven arms, 356 eyes; one randomized controlled trial (RCT), four observational were included. Mean intraocular pressure (IOP) reduction was 10.34 mmHg (HKSJ 95% CI 7.54–13.14; 95% PI: 2.25–18.43 mmHg; I2 = 97.2%, indicating substantial between-study variability driven primarily by differences in baseline IOP β = +0.61 mmHg; P = 0.004, adjuvant use, and surgical technique; P < 0.001). Surgical success was achieved in 77.1% of eyes (95% CI 65.3–85.8%). Visual acuity improved by 0.329 LogMAR (approximately three Snellen lines; 95% CI 0.220–0.438; P = 0.001). The composite complication rate was 13.2% (95% CI 8.7–19.4%), with I2 = 0% for hypotony, shallow anterior chamber, and hyphema. NPDS resulted in significantly fewer reinterventions (7.4% versus 14.1%; P = 0.046) and better corneal clarity preservation (92.4% versus 83.4%; P = 0.013) than non-NPDS procedures. Evidence comparing NPDS and conventional surgery in PCG remains limited. Surgery achieved a mean IOP reduction of 10.34 mmHg (HKSJ 95% CI 7.54–13.14), though estimates showed substantial heterogeneity (I2 = 97.2%). While NPDS may be associated with lower reintervention rates and improved corneal clarity, no definitive differences in primary efficacy were observed. These findings require confirmation in well-designed prospective studies. PROSPERO registration: CRD420251121650. Primary congenital glaucoma damages the optic nerve from birth by obstructing aqueous outflow, and surgery, not medication, is the only way to prevent blindness. Standard operations (trabeculotomy, trabeculectomy) create a drainage channel by cutting through the full thickness of the ocular wall, whereas nonpenetrating deep sclerectomy (NPDS) dissects to the inner trabecular layer without breaching it, with the theoretical benefit of avoiding sudden postoperative hypotony and reducing lifetime infection risk. Whether this anatomical compromise preserves efficacy was the question we set out to answer. Searching seven databases through December 2025, we identified five comparative studies involving 356 eyes across four countries, all with at least 6 months’ follow-up. Pooled analysis showed a mean intraocular pressure (IOP) reduction of 10.34 mmHg (95% CI 7.54–13.14), surgical success in 77% of eyes, and a mean visual acuity improvement of 0.33 LogMAR. The results are broadly comparable to conventional surgery, yet interstudy heterogeneity was extreme (I2 = 97.2%), driven more by differences in baseline IOP, adjuvant mitomycin use, and surgeon experience than by anything intrinsic to the technique itself. The evidence has real limits: only one randomized trial was found, two studies carried serious risk of bias, and success was defined differently across centers. NPDS appears effective and safe. Whether it is better than conventional surgery, or in which patients it should be preferred, remains genuinely open. Answering that will require larger randomized trials with standardized outcome criteria.