Yes / Congenital achromatopsia or rod monochromatism is a rare autosomal recessive condition
defined by a severe loss of cone photoreceptor function in which rods purportedly retain normal or
near-to-normal function. This report describes the results of electroretinography in two siblings with
CNGB3-associated achromatopsia.
Full field light- and dark-adapted electroretinograms (ERGs) were recorded using standard
protocols detailed by the International Society for Clinical Electrophysiology of Vision (ISCEV). We also
examined rod-mediated ERGs using series of stimuli that varied over a 6 log unit range of retinal
illuminances (−1.9–3.5 log scotopic trolands).
Dark-adapted ERGs in achromatopsia patients exhibited severely reduced b-wave amplitudes
with abnormal b:a ratios (1.3 and 0.6). In comparison, the reduction in a-wave amplitude was less
marked. The rod-mediated ERG took on an electronegative appearance at high-stimulus illuminances.
Although the defect that causes achromatopsia is primarily in the cone photoreceptors, our
results reveal an accompanying disruption of rod function that is more severe than has previously been
reported. The differential effects on the b-wave relative to the a-wave points to an inner-retinal locus for
the disruption of rod function in these patients.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/15500 |
| Date | 2017 September 1920 |
| Creators | Maguire, John, McKibbin, M., Khan, K., Ali, M., Kohl, S., McKeefry, Declan J. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, Accepted manuscript |
| Rights | © 2018 Taylor & Francis. The Version of Record of this manuscript has been published and is available in Ophthalmic Genetics in 2018 at https://doi.org/10.1080/13816810.2017.1368087., Unspecified |
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