Researchers have developed a noninvasive technique that can capture images of rod and cone photoreceptors with unprecedented detail. The advance could lead to new treatments and earlier detection for retinal diseases such as macular degeneration, a leading cause of vision loss.

«We are hopeful that this technique will better reveal subtle changes in the size, shape and distribution of rod and cone photoreceptors in diseases that affect the retina,» said research team leader Johnny Tam from the National Eye Institute. «Figuring out what happens to these cells before they are lost is an important step toward developing earlier interventions to treat and prevent blindness.»

In Optica, The Optical Society’s (OSA) journal for high impact research, the researchers show that their new imaging method overcomes resolution limitations imposed by the diffraction barrier of light. The researchers accomplish this feat while using light that is safe for imaging the living human eye.

«The diffraction limit of light can now be routinely surpassed in microscopy, which has revolutionized biological research,» said Tam. «Our work represents a first step toward routine sub-diffraction imaging of cells in the human body.»

Using less light to see more

Achieving high-resolution images of photoreceptors in the back of the eye is challenging because the eye’s optical elements (such as lens and cornea) distort light in a way that can substantially reduce image resolution. The diffraction barrier of light also limits the ability of optical instruments to distinguish between two objects that are too close together. Although there are various methods for imaging beyond the diffraction limit, most of these approaches use too much light to safely image living human eyes.

Story Source: Materials provided by The Optical Society. Note: Content may be edited for style and length.