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Cone photoreceptor classification in the living human eye from photostimulation-induced phase dynamics
- Source :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Year :
- 2019
- Publisher :
- Proceedings of the National Academy of Sciences, 2019.
-
Abstract
- Significance The three spectral types of cone photoreceptors underlie color perception and are largely responsible for inherited and acquired color vision anomalies. In vivo mapping of the trichromatic cone mosaic by imaging provides the most direct and quantitative means to assess the role of photoreceptors in color vision, but remains challenging because cone reflections only weakly differentiate cone types. Here, we show a noninvasive light microscopy modality that reveals the cell’s spectral type, using the optical phase change that arises within the cell when stimulated with light. Our procedure is orders of magnitude faster and more accurate than prior approaches and makes in vivo cone classification promising for a much wider range of color vision applications.<br />Human color vision is achieved by mixing neural signals from cone photoreceptors sensitive to different wavelengths of light. The spatial arrangement and proportion of these spectral types in the retina set fundamental limits on color perception, and abnormal or missing types are responsible for color vision loss. Imaging provides the most direct and quantitative means to study these photoreceptor properties at the cellular scale in the living human retina, but remains challenging. Current methods rely on retinal densitometry to distinguish cone types, a prohibitively slow process. Here, we show that photostimulation-induced optical phase changes occur in cone cells and carry substantial information about spectral type, enabling cones to be differentiated with unprecedented accuracy and efficiency. Moreover, these phase dynamics arise from physiological activity occurring on dramatically different timescales (from milliseconds to seconds) inside the cone outer segment, thus exposing the phototransduction cascade and subsequent downstream effects. We captured these dynamics in cones of subjects with normal color vision and a deuteranope, and at different macular locations by: (i) marrying adaptive optics to phase-sensitive optical coherence tomography to avoid optical blurring of the eye, (ii) acquiring images at high speed that samples phase dynamics at up to 3 KHz, and (iii) localizing phase changes to the cone outer segment, where photoactivation occurs. Our method should have broad appeal for color vision applications in which the underlying neural processing of photoreceptors is sought and for investigations of retinal diseases that affect cone function.
- Subjects :
- Adult
Male
retina
Medical Sciences
genetic structures
Color vision
01 natural sciences
adaptive optics
Photostimulation
010309 optics
Young Adult
03 medical and health sciences
chemistry.chemical_compound
Engineering
Optics
Optical coherence tomography
0103 physical sciences
Image Processing, Computer-Assisted
medicine
Humans
cone classification
Adaptive optics
030304 developmental biology
Physics
0303 health sciences
Retina
optical coherence tomography
Multidisciplinary
Color Vision
medicine.diagnostic_test
business.industry
Retinal
Biological Sciences
Middle Aged
eye diseases
medicine.anatomical_structure
chemistry
Physical Sciences
Retinal Cone Photoreceptor Cells
Human eye
sense organs
business
Photic Stimulation
Tomography, Optical Coherence
Visual phototransduction
Subjects
Details
- ISSN :
- 10916490 and 00278424
- Volume :
- 116
- Database :
- OpenAIRE
- Journal :
- Proceedings of the National Academy of Sciences
- Accession number :
- edsair.doi.dedup.....631058b343b9c88fe87c5ff014fc442d
- Full Text :
- https://doi.org/10.1073/pnas.1816360116