Document Type



Doctor of Philosophy (PhD)



First Advisor's Name

Richard A. Bone

First Advisor's Committee Title

Committee chair

Second Advisor's Name

John T. Landrum

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Yesim Darici

Third Advisor's Committee Title

committee member

Fourth Advisor's Name

Prem P. Chapagain

Fourth Advisor's Committee Title

committee member


Macular Pigment, Lens Optical Density, Cataract, Heterochromatic Flicker Photometry(HFP), Lutein, Zeaxanthin, Meso-Zeaxanthin, Scotopic Threshold

Date of Defense



Age related macular degeneration (AMD) is one of the leading causes of blindness amongst the elderly. Macular pigment (MP) in the retina has been established to protect individuals against AMD. Improving levels of MP by diet or supplements is the constant quest of clinical practitioners and researchers, thus necessitating development of instruments capable of repeatable and reliable MP measurement. Cataract, a consequence of the rising opacity levels of the lens with age is one of the other major causes of blindness in the world. Mapcatsf, a LED-based microprocessor-controlled heterochromatic flicker photometer (HFP) using photopic vision is capable of measuring the levels of MP and the opacity of the lens in terms of optical density.

Test-retest measurements conducted on 83 subjects were analyzed for repeatability in macular pigment optical density (MPOD) measurements. Reliability of the lens optical density (LOD) measurements were tested and compared with those obtained at absolute scotopic thresholds for 25 individuals. A supplement study with 32 individuals both in the young (50) age groups for 6 months further established Mapcatsf’s capacity to monitor changing levels of MP in individuals. As an overall outcome, high levels of repeatability and reliability were obtained in MPOD and LOD measurements establishing Mapcatsf as an instrument for use in clinical settings in the future.



Included in

Physics Commons



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