Structural Reversal of Disc Cupping After Trabeculectomy Alters Bruch Membrane Opening-Based Parameters to Assess Neuroretinal Rim.

OBJECTIVE

To assess the impact of trabeculectomy for glaucoma on morphometric neuroretinal parameters of the optic nerve head (ONH) using spectral-domain optical coherence tomography (SD-OCT).

DESIGN

Retrospective, interventional case series.

METHODS

Participants: Eighty-eight eyes of 88 patients who underwent trabeculectomy with mitomycin C in 2016.

INTERVENTION

All patients underwent trabeculectomy in 1 eye (study eye) and had evaluable SD-OCT examinations of the ONH to measure neuroretinal tissue before and at least at 1 of the 3-, 6-, and 12-month follow-up time points after surgery.

MAIN OUTCOME MEASURES

Longitudinal change in Bruch membrane opening minimum rim width (BMO-MRW), Bruch membrane opening minimum rim area (BMO-MRA), peripapillary retinal nerve fiber layer (RNFL) thickness, intraocular pressure (IOP), and mean deviation in perimetry.

RESULTS

In study eyes, BMO-MRW significantly increased postsurgically comparing baseline and follow-up examinations at 3 months (P = .012), at 6 months (P = .007), and at 1 year (P = .010) after trabeculectomy. The increase in BMO-MRW 6 months after surgery correlated with IOP reduction (r = 0.48; P = .001). BMO-MRA showed an equal increase (P ≤ .034). RNFL thickness remained stable between baseline and follow-up at 3, 6, and 12 months and showed a moderate loss after 18 months (P = .021) of follow-up.

CONCLUSIONS

Structural reversal of disc cupping after trabeculectomy markedly influences Bruch membrane opening-based parameters for up to more than 1 year. Improvement in morphometry seems to correlate with the reduction of IOP while visual field function appears not to be influenced. In longitudinal follow-up of glaucoma patients by SD-OCT, evaluation of BMO-based parameters necessitates to reflect bias caused by surgery.