In vivo functional imaging of human cone photoreceptors

Ravi S. Jonnal, Jungtae Rha, Yan Zhang, Barry Cense, Weihua Gao, Donald T. Miller

Research output: Contribution to journalArticlepeer-review

146 Citations (Scopus)


We evaluate a novel non-invasive optical technique for observing fast physiological processes, in particular phototransduction, in single photoreceptor cells in the living human eye. The method takes advantage of the interference of multiple reflections within the outer segments (OS) of cones. This self-interference phenomenon is highly sensitive to phase changes such as those caused by variations in refractive index and scatter within the photoreceptor cell. A high-speed (192 Hz) flood-illumination retina camera equipped with adaptive optics (AO) is used to observe individual photoreceptors, and to monitor changes in their reflectance in response to visible stimuli ("scintillation"). AO and high frame rates are necessary for resolving individual cones and their fast temporal dynamics, respectively. Scintillation initiates within 5 to 10 ms after the onset of the stimulus flash, lasts 300 to 400 ms, is observed at visible and near-infrared (NIR) wavelengths, and is highly sensitive to the coherence length of the imaging light source. To our knowledge this is the first demonstration of in vivo optical imaging of the fast physiological processes that accompany phototransduction in individual photoreceptors. (c) 2007 Optical Society of America.

Original languageEnglish
Pages (from-to)16141-16160
Number of pages20
JournalOptics Express
Issue number24
Publication statusPublished - 26 Nov 2007
Externally publishedYes


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