Scientists, including one of Indian-origin, have created the most detailed map to date of a region of the human eye long associated with blinding diseases, such as age-related macular degeneration.The high-resolution molecular map developed by University of Iowa researchers catalogues thousands of proteins in the choroid, which supplies blood and oxygen to the outer retina, itself critical in vision.By seeing differences in the abundance of proteins in different areas of the choroid, the researchers can begin to figure out which proteins may be the critical actors in vision loss and eye disease."This molecular map now gives us clues why certain areas of the choroid are more sensitive to certain diseases, as well as where to target therapies and why," said Vinit Mahajan, assistant professor in ophthalmology at the UI and corresponding author on the research paper."Before this, we just didn't know what was where.What vision specialists know is many eye diseases, including age-related macular degeneration (AMD), are caused by inflammation that damages the choroid and the accompanying cellular network known as the retinal pigment epithelium (RPE)."Yet they've been vexed by the anatomy: Why does it seem that some areas of the choroid-RPE are more susceptible to disease than others, and what is happening at the molecular level?" said Mahajan.The researchers set about to answer that question with non-diseased eye tissue donated by three deceased older individuals through the Iowa Lions Eye Bank.Mahajan and Jessica Skeie, a post-doctoral researcher in ophthalmology at the UI, created a map that catalogues more than 4,000 unique proteins in each of the three areas of the choroid-RPE: the fovea, macula, and the periphery.The researchers can now see which proteins are more abundant in certain areas, and why. One such example is a protein known as CFH, which helps prevent a molecular cascade that can lead to AMD.The researchers learned, though the map, that CFH is most abundant in the fovea. That helps, because now they know to monitor CFH abundance there; fewer numbers of the protein could mean increased risk for AMD, for instance.

"Now you can see all those differences that you couldn't see before," Mahajan, whose primary appointment is in the Carver College of Medicine.The study was published in the journal JAMA Ophthalmology.