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Singing A Fun Farewell Song

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Earlier in the month, I posted a photo taken during the retirement ceremony of Paul Sieving, director of the NIH’s National Eye Institute. I’ve since discovered this video recording of the song that I played for Paul during the ceremony. It’s the popular 1970s song, “I Can See Clearly Now” with special lyrics to mark the occasion. Credit: National Eye Institute

Best Wishes to Paul Sieving

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Sieving Farewell Ceremony
Best wishes to my friend Paul Sieving (left) upon his retirement as director of NIH’s National Eye Institute (NEI), On September 5, 2019, I joined the NIH family at a special ceremony to thank Paul for his nearly 20 years of leadership and scientific achievement at NEI. Afterwards, we posed for this photograph and to talk about old times. Paul and I were colleagues at the University of Michigan 30 years ago. In the next chapter of his research career, Paul will join the faculty at the University of California, Davis, where he will establish its Center for Ocular Regenerative Therapy. All the very best, Paul! Credit: NIH

Studying Color Vision in a Dish

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Credit: Eldred et al., Science

Researchers can now grow miniature versions of the human retina—the light-sensitive tissue at the back of the eye—right in a lab dish. While most “retina-in-a-dish” research is focused on finding cures for potentially blinding diseases, these organoids are also providing new insights into color vision.

Our ability to view the world in all of its rich and varied colors starts with the retina’s light-absorbing cone cells. In this image of a retinal organoid, you see cone cells (blue and green). Those labelled with blue produce a visual pigment that allows us to see the color blue, while those labelled green make visual pigments that let us see green or red. The cells that are labeled with red show the highly sensitive rod cells, which aren’t involved in color vision, but are very important for detecting motion and seeing at night.


Lens Crafting

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Credit: Salma Muhammad Al Saai, Salil Lachke, University of Delaware, Newark

Live long enough, and there’s a good chance that you will develop a cataract, a clouding of the eye’s lens that impairs vision. Currently, U.S. eye surgeons perform about 3 million operations a year to swap out those clouded lenses with clear, artificial ones [1]. But wouldn’t it be great if we could develop non-surgical ways of preventing, slowing, or even reversing the growth of cataracts?  This image, from the lab of NIH-grantee Salil Lachke at the University of Delaware, Newark, is part of an effort to do just that.

Here you can see the process of lens development at work in a tissue cross-section from an adult mouse. In mice, as in people, a single layer of stem-like epithelial cells (far left, blue/green) gives rise to specialized lens cells (middle, blue/green) throughout life. The new cells initially resemble their progenitor cells, displaying nuclei (blue) and the cytoskeletal protein actin (green). But soon these cells will produce vast amounts of water-soluble proteins, called crystallins, to enhance their transparency, while gradually degrading their nuclei to eliminate light-scattering bulk. What remains are fully differentiated, enucleated, non-replicating lens fiber cells (right, green), which refract light onto the retina at the back of the eye.


Creative Minds: Reprogramming the Brain

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Cells of a mouse retina

Caption: Neuronal circuits in the mouse retina. Cone photoreceptors (red) enable color vision; bipolar neurons (magenta) relay information further along the circuit; and a subtype of bipolar neuron (green) helps process signals sensed by other photoreceptors in dim light.
Credit: Brian Liu and Melanie Samuel, Baylor College of Medicine, Houston.

When most people think of reprogramming something, they probably think of writing code for a computer or typing commands into their smartphone. Melanie Samuel thinks of brain circuits, the networks of interconnected neurons that allow different parts of the brain to work together in processing information.

Samuel, a researcher at Baylor College of Medicine, Houston, wants to learn to reprogram the connections, or synapses, of brain circuits that function less well in aging and disease and limit our memory and ability to learn. She has received a 2016 NIH Director’s New Innovator Award to decipher the molecular cues that encourage the repair of damaged synapses or enable neurons to form new connections with other neurons. Because extensive synapse loss is central to most degenerative brain diseases, Samuel’s reprogramming efforts could help point the way to preventing or correcting wiring defects before they advance to serious and potentially irreversible cognitive problems.


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