Novel Imaging Technique Reveals New Details on Rare Eye Disorder

A novel imaging technique allowed experts from the National Eye Institute to determine that retinal lesions due to vitelliform macular dystrophy vary by genetic mutations. Addressing the differences in mutations may be the key to creating effective treatments for a rare eye disorder.

Imaging Technique Reveals Genetic Mutation Linked to Rare Eye Disorder

Michael F Chiang, M.D., The Director of NEI says that the agency's long-term investments in imaging technology are beginning to change our perception of eye diseases. Stating that the study is only an example of how improvements in imaging can reveal subtle details regarding the pathology of rare eye diseases that can inform the development of new and effective therapeutics.

The study published in the journal Investigative Ophthalmology & Visual Science, titled "Photoreceptor and Retinal Pigment Epithelium Relationships in Eyes With Vitelliform Macular Dystrophy Revealed by Multimodal Adaptive Optics Imaging," discussed that vitelliform macular dystrophy is an inherited genetic disease causing progressive vision loss via degeneration of the light-sensing retina. The genes implicated in the disease include BEST1, PRPH2, IMPG1, and IMPG2. Depending on which genes and mutations, the age of onset and severity of the disease vary widely.

All forms of rare eye disease have a lesion in the eye's central retina - the macula, that looks similar to egg yolk and is a build-up of toxic fatty material - lipofuscin. VMD affects roughly 1 in 5,500 Americans. As of now, there are no treatments for the rare disorder.

The head of the NEI Clinical and Translational Imaging Unit and co-author of the study, Johnny Tam, Ph.D., used multimodal imaging to observe the retinas of patients diagnosed with VMD at the NIH Clinical Center. The imaging uses adaptive optics, a technique employing deformable mirrors to improve the image resolution, to view live cells in the patient's retina, including light-sensing photoreceptors, blood vessels, and retinal pigment epithelial, in unprecedented detail, reports ScienceDaily.

Together with his team, researchers characterized 11 participants using genetic tests and clinical assessments. Then clinicians evaluated their retinas using the novel imaging technique. Assessment of the cell densities near the VMD lesions showed differences in cell density according to different mutations.

IMPG1 and IMPG2 mutations showed a greater effect on photoreceptor densities than RPE cell density. However, the opposite was true for mutations of BEST1 and PRPH2. In participants with only one eye affected by the rare disorder, researchers noted similar effects on the density of cells as the unaffected eye, despite lacking lesions.

What is Vitelliform Macular Dystrophy?

VMD is a genetic eye disorder causing progressive vision loss. Only after the retina, the specialized light-sensitive tissue lines the back of the eye. Specifically, the disease disrupts cells in a small area near the center of the retina, the macula, according to MedlinePlus.

The rare eye disorder causes the fatty yellow pigment to build up in the cells of the macula. Over time, the substance's large accumulation damages cell vital for clear central vision. This results in people often losing their central vision, and their eyes become blurry and distorted.

On the other hand, it does not affect a person's peripheral vision or ability to see at night.

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