Date of Degree

12-2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Program

Vision Science

Advisor

Jeffrey C. Rabin

Advisor

Brian K. Foutch

Advisor

Christopher M. Putnam

Advisor

Julie A. Lovell

Abstract

This dissertation investigated the mechanisms and applications for optimizing color vision performance across diverse contexts. In a world where color cues augment critical decisions to optimize performance and safety in transportation (e.g., aviation, railway), military, law enforcement, medical diagnostics, and myriad occupational tasks, deficiencies in color perception pose significant challenges. By uniting four interrelated studies, this work explored intrinsic retinal processes, assistive technologies for deficiencies, and novel pathways that challenge conventional understandings of vision. The research bridged fundamental vision science with applications in occupational settings, low vision rehabilitation, and clinical diagnostics, ultimately aiming to optimize color performance.

The first study examined macular pigment (MP), an intrinsic yellow filter in the retina that absorbs short-wavelength light, which provides photoprotection and offers visual performance benefits. Its role in color performance was probed using the Cone Contrast Test (CCT), a tool employed in operational and professional assessments. By evaluating MP optical density’s influence on CCT performance, this chapter elucidated how this built-in filter subtly shapes color vision.

The second study addressed acquired color vision deficiencies (CVD) stemming from ocular diseases. This feasibility study tested color-correcting lenses (CCLs) as a low-vision aid, assessing their ability to improve color performance in affected individuals. This work highlighted CCL’s potential as a non-invasive intervention and opened avenues for rehabilitation in patients with deteriorating color vision due to pathology.

The third study extended this to hereditary CVD, evaluating the efficacy of CCLs in occupational contexts. Despite prior research, evidence for CCLs enabling individuals to pass rigorous professional color screening tests remained inconclusive. Using advanced multi-notch filter technology, the study measured improvements in functional outcomes and neural processing to ascertain whether these lenses met stringent occupational standards and enhanced workplace performance for those with inherited deficiencies.

The fourth study shifted focus to the melanopsin pathway, mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs), which traverse the retinal region lacking rods and cones known as the anatomical blind spot. This chapter focused on development of a rapid threshold-based assessment called the Blind Spot Vision Test (BSVT) to demonstrate detectable light perception through ipRGC signals in the blind spot. The BSVT served as a novel tool for evaluating melanopsin integrity, with implications for clinical diagnostics and interventional research, and broadened our understanding of non-image-forming vision.

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REVISED as of 10-22-25 for Final Review
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