This section describes efficacy outcomes from the published literature that the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
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.