Jason Porter

BS (’97), PhD (’04) optics

(This profile appears at the University of Houston College of Optometry website.)  

Visual quality is limited by a host of factors, including imperfections (or aberrations) in the optics of the eye and the health of various cell types in the retina used to detect light and process this information for subsequent delivery to the brain.

Using psychophysical, optical and functional imaging techniques, my primary goal is to better understand how the eye's optics and structure of the retina and optic nerve head affect vision in normal and diseased eyes.

After completing my BS degree in Optics from the University of Rochester in 1997, I continued my graduate work in Optics at the University of Rochester's Institute of Optics under the advisement of David Williams. My graduate research focused on constructing a clinical wavefront sensor to measure the optical quality of a large population of normal and postoperative laser refractive surgery eyes, and on investigating the sources of aberrations induced in conventional and customized LASIK (laser in-situ keratomileusis) procedures.

In collaboration with Ian Cox (Bausch & Lomb) and Scott MacRae (University of Rochester), I examined changes in the eye’s optical quality after cutting a corneal flap and after performing a laser ablation, how aberrations were induced due to static shifts of the pupil (such as changes in pupil center location with dilation), and characterized dynamic eye movements that occur during surgery. I also assisted in the design of the Rochester Adaptive Optics Ophthalmoscope, an instrument capable of both imaging individual photoreceptors and of conducting visual psychophysics in living human eyes.

Upon receiving my PhD in Optics in 2004, I conducted my postdoctoral work with David Williams at the Center for Visual Science (University of Rochester) in the area of high-resolution retinal imaging using adaptive optics. Adaptive optics is a relatively new technology that can measure and correct for the eye’s aberrations, leading to substantial improvements in image quality when a subject looks through an adaptive optics system. Conversely, the same instrument can provide an extremely sharp view of a subject’s retina with the capability of imaging individual cells in a living eye.

As a postdoc, I contributed to the construction of a fluorescence adaptive optics scanning laser ophthalmoscope (AOSLO) that can noninvasively acquire in vivo reflectance and fluorescence images of individual photoreceptors, ganglion cells and retinal pigment epithelium cells.

In September 2006, I joined the faculty at the University of Houston’s College of Optometry.

Our lab’s main goals are to learn more about the mechanisms responsible for the development and progression of retinal diseases (such as glaucoma and photoreceptor-based degenerations) and how the retina develops in the normal eye. To this end, we have built a dual deformable mirror, fluorescence AOSLO to image single cells in living eyes, thereby allowing us to conduct experiments that could only otherwise have been done in excised tissue.

These experiments are often complimented with the use of other clinical and research-based imaging techniques (such as spectral domain optical coherence tomography) and visual function examinations (including perimetry, electroretinography, etc.) to investigate structure-function relationships. Several projects in the lab revolve around imaging retinal and optic nerve head structures in normal and glaucomatous eyes, as well as in eyes with color vision deficiencies and retinal disease.

For example, through our currently funded NIH R01 grant , we seek to better understand the relation between in vivo changes in lamina cribrosa and optic nerve head geometry, axonal damage and vision loss in glaucoma. We also conduct engineering research, often to help facilitate our scientific goals, in areas such as optimal methods for controlling deformable mirrors and non-traditional methods of wavefront sensing and adaptive optics correction.

Our AOSLO provides the opportunity to non-invasively monitor normal and diseased retinal structure and function on a cellular level in the same eyes over time. The ability to see cellular structures in vivo could enhance our ability to better diagnose retinal diseases and track the efficacy of potential treatments.