Predictive potential of optical coherence tomography parameters for the prognosis of decreased visual acuity after trabeculectomy in open-angle glaucoma patients with good vision

Trabeculectomy (trab) is the most effective surgical procedure for lowering IOP and preventing glaucoma progression. However, decline in best-corrected visual acuity (BCVA) is one of the most serious postoperative complications of trab. Here, we investigated methods to predict decreased BCVA after trab in glaucoma patients with good preoperative BCVA.

This study included 35 eyes of 35 open-angle glaucoma (OAG) patients (male / female: 21 / 14, age: 64.0 ± 9.7 years old, preoperative intraocular pressure: 15.9 ± 5.4 mmHg, mean deviation: -18.1 ± 5.6 dB) with preoperative BCVA of 0.7 or better who underwent trab and were observed for more than 12 months. As a preoperative analysis, we measured temporal quadrant circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and ganglion cell complex thickness in a central strip between the disc and fovea (csGCCT), an area that corresponds to the location of the papillomacular bundle (PMB) in swept-source optical coherence tomography (OCT). We defined BCVA decline as a loss of more than 3 lines of BCVA after 12 months. Measurement parameters were compared between the BCVA-decline group and the non-BCVA-decline group.

BCVA decline was detected in 11 cases (31.4%) 12 months after trab. There was a statistically significant difference in axial length (P = 0.049). A single logistic analysis showed that the BCVA-decline group had significantly lower cpRNFLT than the non-BCVA-decline group (27.7 ± 8.0 μm vs. 45.1 ± 5.3 μm, P < 0.001, cut-off value: 33.4 μm), as well as lower csGCCT (72.4 ± 7.7 μm vs. 87.5 ± 5.1 μm, P = 0.002, cut-off value: 82.3 μm). Multivariable logistic analysis showed that the BCVA-decline group had significantly lower temporal quadrant cpRNFLT (P < 0.001) and lower middle csGCCT (P < 0.001) compared to the non-BCVA-decline group.

Lower temporal quadrant cpRNFLT and middle csGCCT, OCT scan areas that correspond to the location of the PMB, might be biomarkers that predict BCVA decline after trab in OAG patients with good vision.