A new method for imaging the human retina gave researchers the first look at individual retinal ganglion cells (RGCs).

This technique could enable ophthalmologists to diagnose diseases like glaucoma much earlier than current technology permits, allowing sight-saving treatment to start sooner.

Healthy adult retina.Research results were published in the Proceedings of the National Academy of Sciences.

A research team from the University of Rochester Medical School devised a method for non-invasively imagining the retinal, which enabled them to identify individual RGCs. RGCs relay visual information to the brain.

The death of RGCs causes glaucoma. The current diagnosis method assesses the thickness of nerve fibers that project from the RGCs to the brain to identify them. By the time a diagnostician notices the thickness increase, patients could have lost 100,000 RGCs or more. Finding the dead RGCs earlier means treatment can start before the patient’s sight is compromised.

The new method, multi-offset detection, modifies an existing technology, confocal adaptive optics scanning light ophthalmoscopy (AOSLO). AOSLO provides access to some individual cells, like photoreceptors, but not individual RGCs.

Using the same apparatus, the researchers collected multiple retinal images, varying the size and the location of the detector used to gather light scattered out of the retina. Combining these images yielded images of individual cells. In animal studies, structures within the cells, like nuclei, were distinguishable.

The same technique works on other types of cells. In macular degeneration, cone photoreceptors are the first to die. Multi-offset detection enabled researchers to assess the health of cones, including those in damaged areas of the retina.

The new technique will be refined to improve its robustness. It “offers the opportunity to evaluate many retinal features that have previously remained inaccessible to imaging in the living eye,” said Ethan Rossi, lead author of the study.