Impact of Biologic and Targeted Synthetic Therapies on Retinal and Choroidal Parameters Assessed by Optical Coherence Tomography Angiography

Background: To compare retinal microvascular parameters assessed by optical coherence tomography angiography (OCTA) among patients with axial spondyloarthritis (axSpA) receiving different biologic and targeted synthetic therapies and to evaluate the association between smoking status and OCTA-derived retinal microvascular parameters. Methods: This cross-sectional study included 159 eyes of 82 patients with radiographic or non-radiographic axSpA receiving tumor necrosis factor inhibitors (TNFi), interleukin-17 inhibitors (IL-17i), or Janus kinase inhibitors (JAKi) for at least one year. At the time of examination, all patients had BASDAI scores below the established threshold for active disease (BASDAI < 4). Comprehensive ophthalmic evaluation and swept-source OCTA imaging were performed. Superficial capillary plexus vessel density and foveal avascular zone (FAZ) areas in both the superficial (SCP) and deep capillary plexus (DCP) were assessed. Statistical analyses were adjusted for age, sex, smoking status, history of uveitis, treatment duration, and ocular variables. Results: Significant differences were observed among treatment groups in the deep foveal avascular zone (DCP-FAZ) area (p = 0.0060). Post hoc analyses demonstrated larger DCP-FAZ values in patients receiving TNFi than in those receiving IL-17i (p = 0.0010), and larger values in the IL-17i group than in the JAKi group (p = 0.0151). No significant differences were observed in superficial FAZ area or superficial capillary plexus vessel density between treatment groups. Patients receiving JAKi were older and had a shorter treatment duration than those in the other groups. Smoking status was associated with a significantly smaller deep FAZ area (p = 0.0019), whereas no significant association was observed for superficial FAZ measurements. A weak positive correlation was found between intraocular pressure and deep FAZ area (r = 0.18, p = 0.0237), and treatment duration was weakly positively correlated with deep FAZ area (rho = 0.16, p = 0.0454). Conclusions: Retinal microvascular parameters differed among patients with axSpA receiving different classes of biologic and targeted synthetic therapies. Differences were observed primarily in the deep FAZ area, while smoking status was also associated with deep retinal microvascular parameters. Because of the cross-sectional design, these findings should be interpreted as associations rather than evidence of treatment effects. OCTA may provide a useful non-invasive method for assessing retinal microvascular characteristics in patients with axSpA. Further longitudinal studies are warranted to clarify the relationship between systemic therapies, smoking status, and retinal microvascular changes.