Viral Anterior Uveitis: Differences in Retinal Vessel Area Density between the Affected and Non-Affected Eye Using Optical Coherence Tomography Angiography.

Purpose: To investigate differences in the retinal vessel area density (VAD) on optical coherence tomography angiography (OCTA) between eyes with unilateral herpetic viral anterior uveitis (VAU) (herpes-simplex virus (HSV) and varicella-zoster virus (VZV)) and the non-affected fellow eye.
Methods: In this monocentric, observational, prospective case series we analyzed the VAD of the macula, optic disc, and peripapillary region in affected and non-affected eyes of 22 patients with HSV-positive and 22 patients with VZV-positive VAU using OCTA. We analyzed also the visual field mean deviation (MD), the retinal nerve fiber layer (RNFL) thickness, Bruch's Membrane Opening-Minimum Rim Width (BMO-MRW), and ganglion cell layer (GCL) thickness on OCT and correlated the results with the different VADs.
Results: The macular VAD in the superficial vascular plexus (SVC) was significant lower in the affected compared to the non-affected eye for both viruses (HSV: 33.0% ± 3.3% vs. 34.7% ± 2.6%, p  = 0.011; adjusted p  = 0.040; VZV: 33.1% ± 3.2% vs. 34.3% ± 2.8%, p  = 0.012; adjusted p  = 0.050). Additionally, the VAD of the peripapillary SVC differed between the affected and non-affected eye for VZV-positive VAU (47.1% ± 6.2% vs. 50.5% ± 6.3%, p  = 0.048, adjusted p  = 0.100). For both HSV-positive and VZV-positive VAU, there were correlations between macular or peripapillary SVC VAD and BMO-MRW, GCL thickness, RNFL thickness or MD of the affected eye.
Conclusion: We observed vascular dysfunction characterized by decreased macular and peripapillary VAD in the superficial plexus on OCTA in eyes with HSV- and VZV-positive VAU compared to non-affected fellow eyes. These changes might be an early sign of glaucomatous damage or may be a direct consequence of the herpes viruses themselves.