Retinal structure in vitamin A deficiency as explored with multimodal imaging

Abstract

To define the retinal structural abnormalities in a patient with vitamin A deficiency. The patient had a complete ophthalmic examination, electroretinography (ERG), short-wave fundus autofluorescence (SW-AF) and spectral domain optical coherence tomography (SD-OCT) imaging. Serum vitamin A levels were measured. A 63-year-old man with alcoholic cirrhosis, sclerosing cholangitis and chronic pancreatitis experienced blurred vision and nyctalopia for over a year. There was no family history of eye disorders or consanguinity. His best-corrected visual acuity was 20/20 in each eye; color vision as determined with Ishihara color plates was normal in each eye. Anterior segment examination was unremarkable. He was pseudophakic in both eyes. Standard ERGs showed non-detectable rod function, a cone-mediated dark-adapted response to the standard flash and borderline reduced cone function. Serum vitamin A levels were below 0.06 mg/L (normal 0.3-1.2 mg/L). Fundus examination revealed numerous round yellow-white lesions along the superior arcade and nasal to the optic nerve in both eyes. These lesions were hypoautofluorescent on SW-AF. SD-OCT cross sections demonstrated that they were focal disruptions distal to the ellipsoid band of the photoreceptors with hyperreflective images bulging up the ellipsoid and region. The retinal pigment epithelium and the inner retina appeared intact. Limited and gradual vitamin A supplementation for over a month (20 000 IU/day) led to a dramatic improvement in retinal function and to the resolution of the symptoms. The retinal lesions remained unchanged. Imaging of this patient with nyctalopia and severe rod dysfunction suggests that the retinal white lesions known to occur in vitamin A deficiency localize to the photoreceptor layer, particularly the outer segment. On OCT, they are reminiscent of lesions observed in genetic diseases with retinoid cycle dysfunction and of drusenoid subretinal deposits, an abnormality commonly associated with age-related macular degeneration.