Adaptive optics SLO imaging opens door to retina details

Adaptive optics scanning laser ophthalmoscope (SLO) imaging allows visualization of the minute details of the retina that were not visible previously and that can help explain visual disturbances, said Srinivas Sadda, MD, Doheny Eye Institute, University of Southern California, Los Angeles.

Adaptive optics imaging is a technology that is relevant in retinal imaging, Dr. Sadda said.

"Biological optical systems contain optical aberrations that are dynamic; that is, they cannot be corrected but there must be continuous adaption," he said. "The aberrations cause blurring of images that strike the retina, which limits the resolution. Adaptive optics tightens blurred optics by addressing the aberrations."

Adaptive optics, first used in astronomy, is now being applied to ophthalmology. The system has an adaptive mirror, which Dr. Sadda said he believes is the most important element. The mirror continually modulates in shape and perfectly matches the aberrations of the waves coming out of the eye.

"The result is a complete, perfect correction in real-time that ultimately can be acquired by a sensor that provides detailed pictures," he said.

One example of the power of the technology is the image of the cone outer segments in a living human eye. The tiny cellular structures were clearly visible. In another patient with cone-rod dystrophy, ring-like abnormalities of the outer segment mosaic were seen, which allowed identification of the cause of a visual disturbance (a ring-like area of paracentral distortion) that previously had been invisible with other imaging.

"Adaptive optics-based retinal imaging technology has opened the door to visualization of the cellular details of the retina," Dr. Sadda said. He speculated that the technology possibly could be applied to age-related macular degeneration to monitor the photoreceptors and disease progression and pathologies of the microvasculature.