Hyperacute Outer Retinal Dysfunction in a Child: A Case Report With 18 Months of Multimodal Imaging Follow-Up

To report a case of hyperacute outer retinal dysfunction (HORD), a rare pediatric outer retinopathy, with 18 months of multimodal imaging follow-up.

Case report with multimodal imaging.

A 3-year-old girl presented with abrupt bilateral vision loss two weeks after a flu-like illness. Examination showed sluggish pupils, attenuated retinal vessels, and blotchy yellowish peripheral pigmentation. Optical coherence tomography demonstrated diffuse ellipsoid zone and external limiting membrane disruption with parafoveal outer nuclear layer thinning. Full-field electroretinography showed extinguished photopic and scotopic responses. She received pulse steroids, intravenous immunoglobulin, oral prednisone, and weekly methotrexate. Parents reported improved visual function from one month, with ambulatory vision regained by three months. Over 18 months, the ellipsoid zone and external limiting membrane partially recovered centrally, parafoveal outer nuclear layer thinning persisted, and cystoid spaces developed in the right eye on tapering of therapy that regressed on dose re-escalation.

This case is consistent with the reported HORD phenotype and adds a descriptive observation of peripheral pigmentation already present at presentation. Visual function improved during immunosuppressive treatment, but a treatment effect cannot be determined from a single uncontrolled case. Whether the cystoid spaces reflect inflammatory or degenerative change remains uncertain.