The effect of trabeculectomy on rates of visual field progression and retinal nerve fiber layer thinning

Abstract

Purpose : To compare the effect of trabeculectomy on the rates of functional (visual field, VF) vs. structural (optical coherence tomography, OCT) glaucoma progression.

Methods : Participants were recruited from the African Descent and Glaucoma Evaluation Study (ADAGES). Eyes that underwent trabeculectomy and had at least 3 good quality Humphrey 24-2 VFs and spectral-domain OCT scans of the retinal nerve fiber layer (RNFL) performed before or after surgery were included for analysis. Rates of mean deviation (MD) and global RNFL thickness change were calculated using a linear mixed effects model.

Results : For VF analysis, 86 eyes before trabeculectomy and 134 eyes after trabeculectomy were included. The mean (95% CI) global rate of progression decreased from -0.41 (-0.52 to -0.30) before surgery to -0.25 (-0.33 to -0.17) dB/year after surgery (39% reduction, p=0.003). For OCT analysis, 20 eyes before trabeculectomy and 90 eyes after trabeculectomy were included. The mean rate of RNFL thinning decreased from -0.65 (-1.78 to 0.47) before surgery to -0.25 (-0.46 to -0.03) um/year after surgery (61% reduction, p=0.008).

Conclusions : Trabeculectomy decreases the rate of progression of VF and OCT global parameters. Despite the smaller sample size, the effect was more evident on OCT and may help better understand the effect of IOP reduction on rates of change of structural and functional parameters in glaucoma.

This is a 2021 ARVO Annual Meeting abstract.