Probing spatial and chromatic vision with small-spot psychophysics
During daytime, most humans are capable of perceiving fine spatial detail and a rich palette of colors. This sensory capacity is remarkable considering our visual percepts are constructed from just three types of photoreceptor signals—those arising from L, M, and S cones. To obtain an accurate estimate of the spatio-chromatic structure of the world, the circuitry of the retina and brain must process the signals originating in cones across space and time. We use single-cone psychophysics to study these processes near the human fovea, where our visual sense is finest.
Structure-function relationships in retinal disease
Degenerative diseases of the outer retina result in the death of rod and cone photoreceptors. These structural losses necessarily occur at the cellular scale, and have traditionally been studied by histology—either in animal models or in post-mortem human tissue. By contrast, much of our knowledge about the functional consequences of degenerative retinal disease has been acquired using relatively coarse tools for probing vision: visual acuity measurements and conventional automated perimetry. To examine structure-function relationships at the cellular scale in living eyes, we use multi-modal adaptive optics high-resolution retinal imaging in conjunction with precise cone-targeted stimulation. The tools we develop to achieve this have the potential to enhance our understanding of how retinal diseases develop, progress, and respond to therapeutic intervention.
Tuten WS, Cooper RF, Tiruveedhula P, Dubra A, Roorda A, Cottaris NP, Brainard DH, Morgan JIW (in press). Spatial summation in the human fovea: do normal optical aberrations and fixational eye movements have an effect? Journal of Vision.
Tuten WS*, Harmening WM*, Sabesan R, Roorda A, Sincich LC (2017). Spatiochromatic interactions between individual cone photoreceptors in the human retina. Journal of Neuroscience, 37(39): 9498-9509.
Tu JH, Foote KG, Lujan BJ, Ratnam K, Qin J, Gorin MB, Cunningham Jr. ET, Tuten WS, Duncan JL, Roorda A (2017). Dysflective cones: Visual function and cone reflectivity in long-term follow-up of acute bilateral foveolitis. American Journal of Ophthalmology Case Reports, 7, 14-19.
Sabesan R*, Schmidt BP*, Tuten WS, Roorda A (2016). The elementary representation of spatial and color vision in the human retina. Science Advances, 2, e1600797.
Wang Q, Tuten WS, Lujan BJ, Holland J, Bernstein PS, Schwartz SD, Duncan JL, Roorda A (2015). Adaptive optics microperimetry and OCT images in macular telangiectasia type 2 retinal lesions show preserved function and recovery of cone visibility. Investigative Ophthalmology and Visual Science, 56(2): 778-786.
Harmening WM*, Tuten WS*, Roorda A, Sincich LC (2014). Mapping the perceptual grain of the human retina. Journal of Neuroscience, 34(16): 5667-5677.
Tuten WS, Tiruveedhula P, Roorda A (2012). Adaptive optics scanning laser ophthalmoscope-based microperimetry. Optometry and Vision Science. 89(5): 563-574.