Purpose: We longitudinally investigated macular function by multifocal electroretinography (mfERG) in a cohort of patients with Vogt-Koyanagi-Harada (VKH) syndrome.

Prospective study.

VKH syndrome was diagnosed in 11 patients (22 eyes) according to history and ocular examinations. They were treated with immunosuppressive agents and the macular function was evaluated using best-corrected visual acuity (BCVA) and mfERG before treatment and one, three, six, and 12 months after treatment.

All investigated patients with VKH syndrome showed active intraocular inflammation at their first visit. A decreased visual acuity (VA) and abnormalities of mfERG were observed in all these patients. VA rapidly improved at one and three months and gradually improved thereafter. All but one eye achieved a BCVA of ≥20/25 at 12 months following treatment. The N1 amplitude and latency were significantly improved at three and six months and continuously improved thereafter. The P1 amplitude and latency were significantly improved at one and three months and progressively improved thereafter. However, the amplitude of N1 and P1 waves was still significantly decreased at 12 months.

Macular function revealed by Snellen chart and mfERG is severely impaired in VKH patients with active uveitis. Treatment with immunosuppressive agents leads to an earlier, faster, and better recovery of VA, and a delayed but limited recovery of macular function as indicated by mfERG at 12 months. MfERG could be an ancillary test that may be useful in guiding therapy of patients with VKH syndrome.