Background/aims: To determine the association of age, presence of optic nerve head drusen (ONHD) and number of previous intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections with inner retinal layer thicknesses in patients with pseudoxanthoma elasticum (PXE).
Methods: In this retrospective case-control study, longitudinal spectral-domain optical coherence tomography imaging data from patients with PXE were compared with controls. A custom deep-learning-based segmentation algorithm was trained and validated to quantify the retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL). The association of age, number of anti-VEGF injections and ONHD with the RNFL and GCL thickness in the outer ETDRS subfields as dependent variables was investigated using mixed model regression.
Results: Fourty-eight eyes of 30 patients with PXE were compared with 100 healthy eyes. The mean age was 52.5±12.9 years (range 21.3-68.2) for patients and 54.2±18.7 years (range 18.0-84.5) for controls. In patients, ONHD were visible in 15 eyes from 13 patients and 31 eyes had received anti-VEGF injections. In the multivariable analysis, age (-0.10 µm/year, p<0.001), the diagnosis of PXE (-2.03 µm, p=0.005) and an interaction term between age and the presence of ONHD (-0.20 µm/year, p=0.001) were significantly associated with the GCL thickness. Including the number of intravitreal injections did not improve the model fit. The RNFL thickness was not significantly associated with any of these parameters.
Conclusions: This study demonstrates a significant association of ageing and ONHD with GCL thinning in patients with PXE, but not with the number of anti-VEGF injections. Given the severity of inner retinal degeneration in PXE, a clinical trial investigating neuroprotective therapy warrants consideration.
Keywords: dystrophy; genetics; optic nerve; retina.
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