Monochromatism: A Review of its Causes, Clinical Features, and Diagnosis
Introduction
Monochromatism is a rare, inherited visual disorder characterized by a significant reduction in the perception of color. It is caused by the dysfunction of cone photoreceptors in the retina, resulting in a significant decrease in color discrimination. In this review, we discuss the causes, clinical features, and diagnosis of monochromatism.
Causes
Monochromatism is an autosomal recessive disorder caused by a single gene mutation (Henkin et al., 2016). The gene responsible for the disorder is the OPN1LW gene, which is located on the X chromosome and encodes for a photopigment that is responsible for mediating color vision (Cai et al., 2014). Mutations in this gene lead to the dysfunction of cone photoreceptors, resulting in achromatic vision (the inability to detect color).
Clinical Features
Patients with monochromatism experience significantly reduced color discrimination, with some patients exhibiting no color perception at all (Henkin et al., 2016). Patients may also experience reduced visual acuity, photophobia, and low contrast sensitivity. Visual field testing may reveal central or peripheral scotomas.
Diagnosis
Monochromatism can be diagnosed with a comprehensive eye examination, including color vision testing and visual field testing. Electroretinography (ERG) can be used to determine the function of cone photoreceptors, while optical coherence tomography (OCT) can be used to detect retinal abnormalities.
Conclusion
Monochromatism is a rare, inherited visual disorder characterized by a significant reduction in the perception of color. It is caused by a single gene mutation, resulting in dysfunction of cone photoreceptors. Clinical features include reduced color discrimination, reduction in visual acuity, photophobia, and scotomas. Diagnosis can be made with comprehensive eye examination and imaging studies.
References
Cai, Y., Zhang, L., Li, D., Chen, Q., Liao, Y., Jiang, Q., & Guo, X. (2014). Novel OPN1LW mutation in a Chinese family with complete achromatopsia. Molecular vision, 20, 500-505.
Henkin, R. I., Greenberg, A. C., Garzia, R. P., & Fujimoto, J. G. (2016). Achromatopsia: Diagnosis, clinical features, and management. Clinical Ophthalmology, 10, 1267-1277.