Analyzing the efficacy of a novel method for detecting achromatopsia
Authors:   Research Center for Medical Genetics, Moscow, Russian Federation, Sukhanova N.V. , Rychkova S.I. ,   Institute for Information Transmission Problems of the RAS (Kharkevich Institute), Moscow, Russian Federation,   Pirogov Russian National Research Medical University, Moscow, Russian Federation,   A.I. Burnazyan Federal Medical Biophysical Center of the Federal Medical Biological Agency of Russia, Moscow, Russian Federation, Likhvantseva V.G. ,   Academy of Postgraduate Education of the Federal Scientific and Clinical Center of the Federal Medical Biological Agency of Russian Federation, Moscow, Russian Federation, Sandimirov R.I. ,   Pirogov Russian National Research Medical University, Moscow, Russian Federation, Kadyshev V.V. ,   Research Center for Medical Genetics, Moscow, Russian Federation, Zinchenko R.A. ,   Research Center for Medical Genetics, Moscow, Russian Federation
Published: June 2024

Aim: to assess the efficacy of a novel method for diagnosing achromatopsia. Patients and Methods: twenty patients with congenital achromatopsia established by genetic testing were enrolled. Sixteen (80%) patients were diagnosed with mutations in the CNGB3 gene and 4 (20%) patients were diagnosed with mutations in the CNGA3 gene. The control group 1 (with eye diseases) included 37 patients with congenital optic atrophy and 5 patients with oculocutaneous albinism. The control group 2 (without eye diseases) included 40 individuals. At the initial stage of the study, we compared the perception of brightness of chromatic and achromatic images in patients with achromatopsia. To this end, we employed our own images with specific characteristics of color tone, lightness (brightness), and saturation. The results of the first phase have demonstrated that for most patients with achromatop-sia, the lightest and least distinguishable images on a white background are blue. In light of this, we developed tests to detect achromatopsia (tests #1 and #2). Each test comprises four gray silhouette images (with a lightness of 80% for test #1 and 50% for test #2) and four blue images (R0/ G255/B255). For the blue images, saturation is maximal (S 100%) in both tests, while luminosity is L 80% for test #1 and L 50% for test #2. Results: all individuals in the control group 2, patients with optic atrophy and oculocutaneous albinism, were able to see all blue and gray images of both tests and easily identified the blue images corresponding to the gray (achromatic) ones. In the first test, 95% of patients with achromatopsia (n=19) were unable to see blue images or distinguish their shape from gray images. In contrast, all patients were able to distinguish the shape of gray images of the same lightness and specify them. In test #2 (L 50%), the majority of patients (n=13, 65%) exhibited difficulties with the shape of blue images. The remaining seven patients (35%) demonstrated the ability to name blue images and match them to gray images. Two of them were diagnosed with mutations in the CNGA3 gene, while five of them were diagnosed with mutations in the CNGB3 gene. Therefore, the cone system disorder in these patients was less severe than in the others. Conclusion: the achromatopsia test, developed on the basis of comparative analysis of perceived luminosity of chromatic and achromatic images, is simple and accessible. This test provides preliminary differential diagnosis with other eye diseases and determines the most appropriate strategy of further examinations to establish the diagnosis. KEYWORDS: achromatopsia, color vision, method to diagnose achromatopsia, color per-ception abnormality, monochromacy, color vision deficiency, color disfunction. FOR CITATION: Sukhanova N.V., Rychkova S.I., Likhvantseva V.G., Sandimirov R.I., Kadyshev V.V., Zinchenko R.A. Analyzing the efficacy of a novel method for detecting achromatopsia. Russian Journal of Clinical Ophthalmology. 2024;24(2):49–54 (in Russ.). DOI: 10.32364/2311- 7729-2024-24-2-1.