Case of adult-onset neuronal intranuclear hyaline inclusion disease with negative electroretinogram

Purpose

To report the findings in a 72-year-old man with neuronal intranuclear hyaline inclusion disease (NIHID) with the negative-type electroretinogram (ERG) and without night blindness.

Methods

Standard ophthalmological examinations including the medical history, measurements of the best-corrected visual acuity and intraocular pressures, slit-lamp biomicroscopy, ophthalmoscopy, spectral-domain optical coherence tomography, fundus autofluorescence, and perimetry were performed. In addition, neurological and electrophysiological examinations were performed.

Results

NIHID was confirmed by skin biopsy. The ophthalmologic examinations revealed sluggish pupillary reflexes without visual disturbances and retinal abnormalities. The amplitudes of the dark-adapted 0.01 ERG was absent, and light-adapted 3 ERG and light-adapted 30 Hz flicker ERG were reduced in amplitude and delayed in implicit time. The rod system was more severely affected than the cone system, indicating that NIHID is classified as one of rod-cone dysfunction syndrome. The dark-adapted 3 ERG consisted of a markedly reduced b-wave with larger a-wave (negative ERG), but the amplitude of a-wave was smaller than normal.

Conclusions

Since the ophthalmoscopical findings and the subjective visual functions may be essentially normal, the characteristic ERG abnormalities can be an important findings in adult-onset NIHID without night blindness.