Factors associated with macular oedema regression and visual outcomes after dexamethasone implant therapy in uveitic macular oedema.

CLINICAL RELEVANCE: Uveitic macular oedema (uveitic macular oedema) is an important cause of visual morbidity in patients with uveitis, highlighting the clinical importance of understanding factors associated with treatment response. BACKGROUND: To identify clinical factors and optical coherence tomography features associated with macular oedema regression and best-corrected visual acuity improvement at 3 months after dexamethasone implant (dexamethasone implant) treatment for non-infectious uveitic macular oedema. METHODS: This retrospective cohort study included patients with non-infectious uveitic macular oedema treated with dexamethasone implant. Baseline demographics and clinical characteristics were collected, including best-corrected visual acuity, central retinal thickness, and intraocular pressure at pre-injection and at 1 and 3 months post-injection. uveitic macular oedema regression was defined as the absence of intraretinal and subretinal fluid on spectral-domain optical coherence tomography at 3 months. The best-corrected visual acuity improvement was defined as a decrease of ≥ 0.1 logMAR, with a ≥ 0.2-logMAR threshold evaluated in a sensitivity analysis. Mixed-effects logistic regression models were used to evaluate associated factors, and first-injection sensitivity analyses were performed to assess the robustness of the findings. RESULTS: A total of 85 dexamethasone implant injections in 48 eyes of 38 patients were analysed. uveitic macular oedema regression at 3 months occurred after 54 injections (63.5%). Higher pre-injection central retinal thickness was independently associated with reduced odds of regression (adjusted odds ratio [OR] per 100-µm increase: 0.362; 95% confidence interval [CI]: 0.194 - 0.675, p = 0.002). Ellipsoid zone disruption was associated with reduced odds of ≥ 0.1-logMAR improvement after adjustment for pre-injection best-corrected visual acuity (adjusted OR: 0.261; 95% CI: 0.084-0.815; p = 0.021). Using the 0.2-logMAR threshold, longer uveitic macular oedema duration and ellipsoid zone disruption remained significant. CONCLUSION: Dexamethasone implant treatment provided favourable short-term anatomical and visual outcomes in patients with non-infectious uveitic macular oedema, although repeat treatment was frequently required. Baseline clinical and optical coherence tomography characteristics were associated with treatment response and may help characterise the expected outcomes following dexamethasone implant treatment.