Achromatopsia: literature review and case study

Abstract

Congenital achromatopsia is a rare macular dystrophy affecting one in 30,000 to 50,000 people. It is associated with five genetic markers, with mutations in the CNGA3 and CNGB3 genes responsible for over 90% of cases. The disease presents with colour vision defect, early onset of visual impairment, photophobia, pendular nystagmus, and an abnormal photopic electroretinogram (ERG). The disease has two forms: incomplete, which is milder due to residual cone function, and complete, which is severe due to the complete absence of cone function. The diagnosis of achromatopsia has been challenging due to the variability in clinical presentations and associated symptoms. The advent of spectral domain optical coherence tomography (SD-OCT) has revolutionized the evaluation and understanding of achromatopsia.
Achromatopsia is a rare macular dystrophy with variable presentation, presenting with a range of symptoms including reduced vision, photophobia, dyschromatopsia, and nystagmus. Diagnostic tests like SD-OCT, fundus autofluorescence, and electrophysiology aid in ruling out distinct aetiologies. Traditional diagnostic methods, such as diminished light-adapted flash photopic ERG and 30 Hz flicker, have been used to diagnose achromatopsia. Recent diagnostic modalities, like SD-OCT, have helped in evaluating achromatopsia, providing a better understanding of the disease. The use of SD-OCT has helped document a progressive degenerative process noted with increased age, with a flattened appearance of the cystic area on OCT. Animal genetic studies have further collaborated on the progressive nature of the disease, with a CNGA3 genetic mutation contributing to the progressive form of the disease.
Achromatopsia is a rare macular dystrophy with variable presentation, presenting with vision reduction, photophobia, dyschromatopsia, and nystagmus [1,2]. Diagnosis traditionally involves a diminished light-adapted flash photopic ERG and 30 Hz flicker, which correlate with the functional loss of cone photoreceptors. Recent diagnostic modalities like SD-OCT have helped in evaluating achromatopsia, giving a better understanding of the disease. Congenital achromatopsia, also known as rod monochromatism, affects one in 30,000 to 50,000 people and is associated with five genetic markers. The disease presents with color vision defects, early visual impairment, photophobia, pendular nystagmus, and abnormal photopic electroretinograms. SD-OCT can help visualize characteristic morphological alterations linked to achromatopsia, aiding in diagnosis and potentially enhancing future therapeutic alternatives.

DOI - https://doi.org/10.65525/SVUP.9788199956094.2026.18-31