Longitudinal OCT changes of the peripapillary RNFL after different glaucoma interventions – a comparative study

BACKGROUND: The study's objective was to investigate the development of the peripapillary retinal nerve fiber layer (pRNFL) thickness after Deep Sclerectomy (DS), XEN microstent implantation and Preserflo (PF) microshunt implantation compared to Trabeculectomy (TE). METHODS: This retrospective monocentric study analyzed eyes with primary open-angle glaucoma (POAG) after TE, DS, XEN- or PF-implantation over 2 years. Intraocular pressure (IOP), number of IOP-lowering medications, best-corrected visual acuity (BCVA), and success rates were analyzed. pRNFL was measured by spectral domain optical coherence tomography (SD-OCT). RESULTS: 462 eyes were analyzed. 108 underwent TE, 183 DS, 90 XEN- and 81 PF-implantation. Mean IOP and mean number of IOP-lowering medications decreased, while BCVA remained stable in all groups. Mean pRNFL significantly decreased in all groups, changing from 64.6 ± 2.0 to 57.8 ± 1.9 μm (-6.8 μm, p < 0.001), 63.6 ± 1.8 to 58.3 ± 2.5 μm (-5.3 μm, p = 0.005), 63.2 ± 2.2 to 60.0 ± 2.1 μm (-3.2 μm, p = 0.008) and 62.1 ± 1.8 to 59.9 ± 1.8 μm (-2.2 μm, p = 0.008) in the TE, DS, XEN and PF groups. Between 1 and 2 years postoperatively, no further statistically significant decline was observed in any group (TE: p = 0.131; DS: p = 0.374; XEN: p = 0.129; PF: p = 0.471). CONCLUSIONS: Despite success in reducing IOP and IOP-lowering medications, the pRNFL declines during the first postoperative year, with no further statistically significant decline observed during the second year.