Abstract
Purpose :
To describe fundus optical imaging and vision characteristics in a patient with Niemann-Pick disease.
Methods :
Retrospective chart review of the case of a young adult male who was incidentally found, in relation to a spectacle prescription consultation, to have a bilateral white perifoveolar ring in both eyes. He was subsequently found to have homozygosity for a pathogenic missense variant in SMPD1 and diagnosed with Niemann-Pick disease, a sphingomyelin lysosomal neural storage disease.
Results :
Visual acuity was 1.0/1.0 in both eyes with correction for myopia -1.0/-0.25 diopters. The patient had no subjective pericentral scotoma. Intraocular pressure was 12 mmHg, and photopic microperimetry was normal in both eyes. Color fundus photography was normal except for the presence of a white ring of inner retinal hyperreflectivity encircling the foveola in both eyes. Optical coherence tomography showed a slight signal reduction of the retina behind the ring, but otherwise the retina and choroid were normal. On infrared scanning laser ophthalmoscopy, the white material was invisible and entirely transparent. The ring was also transparent on adaptive optics fundus photography in 850 nm illumination (rtx1, Imagine Eyes, Orsay, France), but when the cone photoreceptors on either side of the ring were in focus, the photoreceptors behind the ring were out of focus, and vice versa.
Conclusions :
The sphingomyelin in the perifoveolar inner layers of the retina that obstructs the imaging of the deeper layers of the retina in visible light is transparent in infrared, but it shifts the focal plane of the rtx1 adaptive optics camera sufficiently to require an adjustment of its focal plane, possibly because the material increases the refractive index of the nerve fiber layer in the inner retina.
This is a 2021 ARVO Annual Meeting abstract.