The Impact of Clinical Success Levels on Postoperative RNFL Development After Trabeculectomy

Trabeculectomy is the standard surgical treatment for advanced glaucoma, yet the relationship between postoperative intraocular pressure (IOP) and long-term structural preservation remains unclear. We investigated longitudinal changes in peripapillary retinal nerve fiber layer (RNFL) thickness following trabeculectomy in primary open-angle glaucoma and evaluated whether lower postoperative IOP levels are associated with improved structural stability.

This retrospective consecutive case series included 106 eyes undergoing trabeculectomy between 2010 and 2020 with follow-up of up to 5 years. RNFL thickness was assessed using spectral-domain optical coherence tomography at baseline and during follow-up. IOP, glaucoma medication use, best-corrected visual acuity, and visual field mean defect were recorded longitudinally.

Mean IOP decreased from 23.8 ± 0.9 mmHg preoperatively to 10.5 ± 0.7 mmHg at 1 month and remained significantly reduced at 5 years (13.8 ± 0.7 mmHg), with sustained reduction in medication use. RNFL thickness declined significantly from 64.4 ± 2.0 µm during the first postoperative year to 57.2 ± 1.6 µm and subsequently remained relatively stable. While eyes achieving a postoperative IOP <12 mmHg showed no statistically significant RNFL thinning compared to baseline, eyes with higher postoperative IOP exhibited greater structural decline despite meeting conventional success criteria.

Trabeculectomy provides durable IOP reduction; however, early structural loss may still occur. Our findings suggest that lower postoperative IOP levels may be associated with greater structural preservation, although this relationship requires further investigation.