Congenital Achromatopsia: A Case Study and Low Vision Aids

Introduction. Congenital achromatopsia (CA) is predominantly an autosomal recessive disease affecting the retinal cone photoreceptors. The condition affects approximately 1 in 30,000 people. Individuals with CA generally have photophobia, pendular nystagmus, abnormal photopic electroretinogram, and lack of color discrimination. Case Presentation. Presented is a case of CA in a healthy, 24-year-old male. The patient presented with decreased vision since birth that was slightly improved with a spectacle prescription. The patient was unaware of the cause of his decreased vision at initial presentation, although he had been told previously that he “has a problem with his macula.” The patient’s uncorrected distance VA was 2/16 on the METDRS chart (20/160 Snellen equivalent) OD and OS and 0.1/0.8M at 19 near OU. Biomicroscopy revealed an unremarkable anterior segment and fundoscopy revealed mild macular pigmentary changes OU. Deviation From the Expected. The macula was irregular and coincided with an abnormal OCT revealing a hypopigmented area centrally in the fovea OU. In addition, the photopic electroretinogram (ERG) revealed a reduced single-flash b-wave amplitude and a nondetectable 32-hz flicker response OU. Discussion. CA can cause varying degrees of decreased vision ranging from 20/80 to 20/200. Macular appearance varies from a completely normal macular appearance to an atrophic macular lesion and ancillary testing can be used to aid in the diagnosis. Conclusion. CA can be a difficult condition to diagnose without performing additional testing such as an OCT or ERG. While there is no treatment for the condition, low vision aids are often helpful to improve quality of life.