Elsevier

Vision Research

Volume 48, Issue 26, November 2008, Pages 2564-2568
Vision Research

In vivo imaging of the photoreceptor mosaic of a rod monochromat

https://doi.org/10.1016/j.visres.2008.04.006Get rights and content
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Abstract

Complete achromatopsia (i.e., rod monochromacy) is a congenital vision disorder in which cone function is absent or severely diminished, often due to mutations in one of two components of the cone phototransduction cascade (transducin or the cyclic-nucleotide gated channel). Previous histological data concerning cone structure are conflicting; suggesting anywhere from normal numbers of foveal cones to a complete absence of foveal cones. Here, we used an adaptive optics ophthalmoscope to obtain in vivo retinal images from a rod monochromat for whom the genetic basis of the disorder consists of a homozygous mutation in the CNGB3 gene. Behavioral data from the patient were consistent with an absence of cone function. Retinal images revealed a severely disrupted photoreceptor mosaic in the fovea and parafovea, where the size and density of the visible photoreceptors resembled that of normal rods. Imaging of additional rod monochromats to characterize differences in the photoreceptor mosaic between genetically classified patients will be required to determine which, if any, might be receptive to restorative gene therapy procedures.

Abbreviations

CNG
cyclic-nucleotide gated
OCT
optical coherence tomography
ERG
electroretinogram
AO
adaptive optics

Keywords

Cones
Rods
Adaptive optics
Achromatopsia
Retinal disease
Waveguiding

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