Case ReportMOSAICISM AS A PROPOSED MECHANISM FOR ASYMMETRIC RETINAL TESSELLATIONSRaevis, Joseph J. MD; Denisova, Ksenia MD; Mechel, Elzbieta MD; Shrier, Eric M. DOAuthor Information Department of Ophthalmology, SUNY Downstate Medical Center, Brooklyn, NY. Reprint requests: Joseph J. Raevis MD, Department of Ophthalmology, SUNY Downstate Medical Center, 450 Clarkson Avenue, 7th floor, Box #58, Brooklyn, NY 1120; e-mail: [email protected]. None of the authors has any financial/conflicting interests to disclose. Retinal Cases & Brief Reports: May 2021 - Volume 15 - Issue 3 - p 214-217 doi: 10.1097/ICB.0000000000000770 Buy Metrics AbstractIn Brief Background/Purpose: Report a case of markedly asymmetric retinal tessellations and propose mosaicism as a mechanism. Methods and Results: A 59-year-old pseudophakic woman presented with uncorrected 20/20 vision and was found to have markedly different retinal tessellation appearances in both eyes. The axial lengths were 25.66 mm and 25.88 mm in the right and left eyes, respectively, and no significant asymmetrical choroidal thinning was seen on optical coherence tomography or optical coherence tomography angiography. Fluorescein angiogram showed significant hyperfluorescence, representing the underlying choroid, which correlated with the tessellation patterns in the left eye. She had no other ocular or systemic findings such as stripes or whorled skin. Conclusion: This is the first reported case of markedly asymmetric retinal tessellation patterns that are not due to asymmetric axial myopia or choroidal thinning. We propose that mosaicism is a possible mechanism causing this finding. A 59-year-old woman presented with markedly different retinal tessellation appearance that could not be explained by axial myopia or choroidal thinning. Mosaicism is known to affect the color of the iris and we propose that this same mechanism may have a similar effect on the tessellation pattern of the retina.