Full-field electroretinogram (ffERG) over 48 months correlates with baseline retinal dysfunction in Vogt-Koyanagi-Harada disease: a longitudinal study.

OBJECTIVE

To evaluate full-field electroretinogram (ffERG) parameters and evaluate their clinical associations in patients with acute Vogt-Koyanagi-Harada (VKH) disease over a 4-year follow-up.

METHODS AND ANALYSIS: This retrospective cohort study included 21 patients with acute VKH disease followed for 48 months after initiation of systemic corticosteroid therapy, with or without adjunctive immunosuppression. ffERG was performed at 1, 6, 12, and 48 months (M) post-treatment. At M48, eyes were classified into two groups: Group 1 (normal ffERG) and Group 2 (subnormal ffERG), based on whether any ffERG parameters fell below the 5th percentile of age-matched healthy controls. Main outcomes included longitudinal ffERG changes, clinical associations, and the 6-month recovery ratios relative to baseline (M1).

RESULTS

All ffERG parameters improved significantly from baseline to M6 (p < 0.001) and to M12 (p < 0.001) and stabilized thereafter. Group 2 exhibited consistently reduced ffERG amplitudes compared to Group 1 throughout follow-up (p < 0.01 to p < 0.001), despite similar recovery trends. Recovery ratios at M6 ranged from 27%-78% in Group 1 and 26%-175% in Group 2; however, Group 2 remained below normal levels at M48. Sunset glow fundus (SGF) at M12 was significantly more frequent in Group 2 (60.7%) than in Group 1 (21.4%, p = 0.025).

CONCLUSIONS

Retinal function improved during the first year and stabilized thereafter, irrespective of treatment type. Persistent subnormal ffERG at 48 months reflected a poorer baseline function and was associated with the development of SGF.