Trabecular stent bypass microsurgery for open-angle glaucoma

4.1 In a systematic review and meta-analysis of 2,143 patients from 32 studies, comparing stent insertion combined with phacoemulsification against phacoemulsification alone in patients with glaucoma and cataract, there was a statistically significant decrease in intraocular pressure (IOP) from baseline in the combined group compared against the phacoemulsification-only group at a follow‑up of 12 to 58 months (standardised mean deviation [SMD] −0.46, 95% confidence interval [CI] −0.87 to −0.06, 4 randomised controlled trials [RCTs], I²=47%, p=0.128). In a systematic review and meta-analysis of 248 patients (5 studies) with mild to moderate glaucoma treated by stent insertion alone, there was a statistically significant reduction in IOP from baseline after implantation of 1 stent at a follow‑up of 6 to 18 months (SMD −1.95, 95% CI −3.41 to −0.49, 3 studies; I²=96%, p=0.000) and of 3 stents at 6‑month follow‑up (SMD −4.26, 95% CI −5.18 to −3.33, 1 study). But there was not a statistically significant reduction in IOP from baseline after implantation of 2 stents at 6 to 12 months (SMD −3.08, 95% CI −6.90 to 0.74, 2 studies; I²=98%, p=0.000). In the same study there was a 22% reduction in IOP from baseline after 1‑stent insertion at 18‑month follow‑up (1 study), and at 6‑month follow‑up there was a 30% reduction in IOP after 2‑stent implantation (2 studies) and a 41% reduction after 3‑stent insertion (1 study).

4.2 In the systematic review and meta-analysis of 2,143 patients there was a statistically significant reduction in the number of topical glaucoma medications used after the procedure in the combined group compared against the phacoemulsification-only group (SMD −0.65, 95% CI −1.18 to −0.12, 3 studies; I²=58%, p=0.092). There was a weighted mean reduction in topical glaucoma medications per patient of 1.33 from baseline after insertion of 1 stent combined with phacoemulsification (3 RCTs), of 1.1 from baseline after insertion of 2 stents combined with phacoemulsification (1 RCT) and of 1.01 after phacoemulsification alone (3 RCTs).

4.3 In an RCT of 239 patients comparing stent insertion combined with phacoemulsification (n=116) against phacoemulsification alone (n=123) in patients with open-angle glaucoma not controlled on 1 medication, the proportions of eyes with corrected distance visual acuity of 20/40 or better in the combined group were 45% (49 eyes) before the procedure and 94% (99 eyes) at 12‑month follow‑up. In the phacoemulsification-only group, the proportions were 44% (53 eyes) before the procedure and 90% (101 eyes) 12 months after the procedure. In an RCT of 192 patients comparing implantation of 2 stents (n=94) against medical therapy (n=98), the proportions of eyes with best corrected visual acuity (BCVA) of 20/40 or better in the stent group were 84% before the procedure and 79% at 12‑month follow‑up. In the medical therapy group, the proportions were 87% before the procedure and 84% at 12‑month follow‑up.

4.4 In the RCT of 192 patients, the vertical cup‑to‑disc ratio had not changed from baseline (change within ±0.2) in 97% (90/93) of patients in the stent group at 1‑year follow‑up, and was worse than baseline (increase of more than 0.2) in 1 patient (n=93). In the medication group, the vertical cup‑to‑disc ratio had not changed from baseline in 99% (88/89) of patients in the stent group at 1‑year follow‑up and was better than baseline (decrease of more than 0.2) in 1 patient (n=89). In an RCT of 119 patients comparing implantation of 1 stent (n=38) against implantation of 2 stents (n=41) or 3 stents (n=40), the mean cup‑to‑disc ratios at 18‑month follow‑up were the same as preoperative values.

4.5 In an RCT of 100 patients comparing stent insertion combined with phacoemulsification (n=50) against phacoemulsification alone (n=50) in patients with open-angle glaucoma and cataract, the successful stent implantation rate was 96% (48/50). In a prospective case series of 19 patients treated by stent implantation and phacoemulsification, the stent was successfully implanted in all eyes (19/19).

4.6 The specialist advisers listed the following key efficacy outcomes: IOP reduction, glaucoma medication use and quality of life.