Title : Comparative outcomes of a newly modified trabeculectomy versus conventional trabeculectomy
Abstract:
This prospective comparative study evaluated the outcomes of a newly modified trabeculectomy (NMT) versus conventional trabeculectomy (trab) in patients with open?angle glaucoma, with a special interest in its usefulness for normal-tension glaucoma.
A total of 121 eyes were analyzed: 27 eyes underwent NMT and 94 eyes underwent conventional trabeculectomy. The two groups were matched for age and preoperative intraocular pressure (IOP). Baseline IOP was identical in both groups, with a median of 18.0 mmHg (interquartile range [IQR] 16.0–21.0), and preoperative glaucoma medication use was also comparable at 3.0 agents (IQR 2.0–4.0).
The NMT technique modifies the scleral flap step in standard trabeculectomy. During surgery, a deep scleral flap is created and removed, extending from the scleral edge beneath the superficial scleral flap to the trabecular meshwork. This deep flap is approximately 1.5 mm wide centrally and is dissected to a depth sufficient to allow visualization of the choroid. This modification is intended to enhance aqueous outflow and thereby improve IOP reduction.
Postoperative outcomes were assessed in terms of IOP, visual acuity, number of medications, complications, and need for additional surgery over a one?year follow?up. At 3 and 6 months after surgery, the NMT group showed significantly lower IOP compared with the conventional trabeculectomy group. At 6 months, the median IOP was 12.0 mmHg (10.0–15.0) in the conventional trabeculectomy group and 8.0 mmHg (7.0–10.0) in the NMT group, with a statistically significant difference (P = 0.03). This indicates a stronger IOP?lowering effect of the modified procedure.
Complications observed included shallow (thin) anterior chamber and choroidal detachment. These occurred in 3.2% of eyes in the conventional trabeculectomy group and 11.1% in the NMT group for each complication, but the overall incidence of complications did not differ significantly between groups.
In conclusion, the newly modified trabeculectomy achieved significantly greater IOP reduction than conventional trabeculectomy at 3 and 6 months postoperatively, without a significant increase in complications. Therefore, NMT is considered a useful surgical option for open?angle glaucoma, particularly for normal-tension glaucoma where achieving lower target IOP is crucial.
