Achromatopsia: Long term visual performance and clinical characteristics.

Area of Science:

• Ophthalmology
• Genetics
• Pediatric Visual Impairment

Background:

• Achromatopsia is an inherited cone dysfunction causing poor color vision, reduced visual acuity, photophobia, and nystagmus.
• It is a significant cause of visual impairment in children, with a global prevalence of 1 in 30,000.

Purpose of the Study:

• To detail the clinical features of achromatopsia.
• To identify the primary causative genes in the studied population.
• To analyze the disease's progression, focusing on visual function stability over time.

Main Methods:

• A retrospective analysis of medical records from 76 achromatopsia patients.
• Patients were categorized into younger (<10 years) and older (≥10 years) groups.
• A subset with long-term follow-up was analyzed for age-related changes.

Main Results:

• CNGA3 gene variants were identified in 73.6% of patients, a higher prevalence than globally reported.
• Common clinical signs include photophobia (96.2%), nystagmus (93.6%), hypermetropia (72.3%), and strabismus (51.1%).
• No age-related decline in visual acuity was observed in the overall cohort, while a subset showed slight improvement with age.

Conclusions:

• CNGA3 is the predominant gene linked to achromatopsia in this population, unlike worldwide distributions.
• Photophobia, nystagmus, and hypermetropia are characteristic findings.
• The condition appears clinically stable, with potential for slight visual acuity improvement over time.