Multimodal imaging has enabled researchers from the National Eye Institute (NEI) in the United States to determine that retinal lesions from vitelliform macular dystrophy (VMD) vary by gene mutation. Addressing the differences may lead to effective treatments for this and other rare diseases.
NEI Director Dr Michael F. Chiang said the study is “just one example of how improved imaging can reveal subtle details about pathology in a rare eye disease that can inform the development of therapeutics”.
VMD is an inherited genetic disease that causes progressive vision loss through degeneration of the retina. Genes implicated include BEST1, PRPH2, IMPG1, and IMPG2. Depending on the gene and mutation, age of onset and severity vary widely. All forms of the disease have in common, a lesion in the central retina that looks like an egg yolk and is a build-up of toxic fatty material called lipofuscin. There is currently no treatment.
The researchers used multimodal imaging with adaptive optics – a technique that employs deformable mirrors to improve resolution – to view live cells in the retina, including the light-sensing photoreceptors, retinal pigment epithelial (RPE) cells, and blood vessels in unprecedented detail.
Assessment of cell densities (photoreceptors and RPE cells) near VMD lesions revealed differences in cell density according to the various mutations. IMPG1 and IMPG2 mutations had a greater effect on photoreceptor cell density than RPE cell density. The opposite was true with PRPH2 and BEST1 mutations. Participants with only one affected eye showed similar effects on cell density in the unaffected eye, despite lacking lesions.
- Liu T., Aguilera N, Bower AJ, Li J, Ullah E, Dubra A, Cukras C, Brooks BP, Jeffrey BG, Hufnagel RB, Huryn LA, Zein WM, Tam J. “Photoreceptor and retinal pigment epithelium relationships in eyes with vitelliform macular dystrophy revealed by multimodal adaptive optics imaging.” July 28, 2022. Investigative Ophthalmology & Visual Science.