Postoperative RNFL-Changes after Successful Trabeculectomy: 2-Year Outcomes

The most important tool in glaucoma therapy is to lower the intraocular pressure to slow down the apoptosis of retinal ganglion cells. Trabeculectomy (TE) is considered the gold standard in glaucoma surgery. The aim of this study was to analyse the postoperative changes in retinal nerve fibre layer (RNFL) using optical coherence tomography (OCT) after TE.

We examined 40 patients naïve to prior glaucoma surgery retrospectively, who received a TE for medically uncontrolled primary open-angle glaucoma (POAG). Intraocular pressure (IOP), IOP-lowering medication, mean deviation of perimetry, visual acuity and peripapillary RNFL-thickness using OCT were evaluated during the first 24 month after TE.

In total 40 eyes from 40 patients were treated with TE. Mean IOP decreased from 25.0 ± 0,9 to 13.9 ± 0.6 (p < 0.01), and the mean number of IOP-lowering eye drops from 3.3 ± 0.2 to 0.5 ± 0.2 (p < 0.01). Visual acuity and mean deviation in perimetry remained stable while mean global RNFL-thickness decreased from 67.8 ± 2.9 to 63.7 ± 2.9 (p < 0.01) and 63.4 ± 2.9 µm (p < 0.01) 12 and 24 months after TE.

The TE is an effective method to reduce the IOD and the amount of IOP-lowering medication. Nevertheless, a significant further loss in RNFL thickness was observed in the first 12 months after TE. Thus, RNFL changes seem to stabilise only after a protracted period.