Intracameral prostaglandin implant vs Timolol in open-angle glaucoma or ocular hypertension: a systematic review and meta-analysis

Purpose

Intracameral prostaglandin implants represent a novel approach to managing intraocular pressure (IOP) in glaucoma patients, potentially addressing adherence issues associated with topical medications. This systematic review and meta-analysis evaluated the comparative safety and efficacy of intracameral prostaglandin implants versus topical timolol in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT).

Design

A systematic review and meta-analysis.

Methods

We systematically searched PubMed, Embase, and Web of Science from inception to September 15, 2024. Randomized controlled trials (RCTs) comparing intracameral prostaglandin implants with topical timolol in adult patients with OAG or OHT were included. Primary outcomes were mean difference (MD) in IOP reduction and adverse events. Risk of bias was assessed using the Revised Cochrane risk-of-bias tool (RoB-2) at the outcome level, and certainty of evidence was evaluated using GRADE methodology.

Results

Seven articles from 5 unique RCTs (2600 participants) were included. Intracameral prostaglandin implants demonstrated early superiority in IOP reduction, which converged with timolol by 12 weeks. At 10 days, implants showed greater IOP reduction compared to timolol (MD -0.942 mmHg, 95 % CI -1.174 to -0.710). At 2 weeks (MD -0.787 mmHg, 95 % CI -0.969 to -0.605) and 6 weeks (MD -0.317 mmHg, 95 % CI -0.589 to -0.045), the difference remained statistically significant but diminished. By 12 weeks, the difference was no longer significant (MD -0.055 mmHg, 95 % CI -0.276 to 0.166). Subgroup analyses suggested the 15 μg bimatoprost dose maintained efficacy longer than 10 μg or 75 μg travoprost doses. Adverse events were more common with implants than timolol, particularly conjunctival hyperemia, eye pain, and iritis. Corneal endothelial cell density decreased more with implants than timolol after 3–20 months (MD -201.640 cells/mm², 95 % CI -284.697 to -118.583). Substantial heterogeneity (I² = 98–100 %) was observed, warranting cautious interpretation.

Conclusions

Intracameral prostaglandin implants are an effective alternative to timolol, offering early IOP reduction advantages that equilibrate over time. While the absolute IOP reduction (< 1 mmHg) falls below typical clinical significance thresholds, implants may offer advantages through improved treatment adherence. The benefit-risk assessment favors lower-dose implants, with the 15 μg bimatoprost implant showing the most sustained efficacy. Longer-term safety monitoring is warranted, particularly regarding corneal effects.