Primate foveas have a distinctive yellow macular pigment that is one of their recognized specializations. The long-term objectives of this application are to test two major nonexclusive hypotheses about the functional roles of the macular pigment. The first hypothesis states that the macular pigment aids in visual resolution in the fovea by absorbing scattered or poorly focussed blue light. A parallel series of experiments will be done with monkeys and humans to examine the relationship of the foveal pigmentation to visual resolution. Monkey retinas will be studied by densitometry, microscopy and image analysis. The macular pigment density distribution, and other foveal features will be characterized. These data will be used to refine monochromatic fundus photography for measuring the macular pigment density in vivo. Humans with high and low amounts of macular pigment measured by the in vivo technique will be compared on a demanding test of visual acuity. The test stimulus will be placed precisely at closely spaced intervals within the foveal avascular zone by image stabilization. An accurate profile of visual acuity in the fovea will be determined. If the resolution hypothesis is correct, humans with higher amounts of macular pigment should have better visual resolving power. The second hypothesis states that the macular pigment protects the fovea from damage by light and oxygen. Protection could occur by absorption of light, quenching of radicals, or breaking chain reactions leading to lipid oxidation. Absorption of light will be measured optically by microdensitometry and image analysis. In the same retinas the concentrations of lutein and zeaxanthin, the carotenoids that comprise the macular pigment, will be measured by high performance liquid chromatography. Serum and other tissues of the same individuals will also be analyzed for carotenoid concentrations. Retinas of monkeys with high and low amount of macular pigment will be assayed for lipid oxidation products. If macular pigment is protective, the retinas low in macular pigment should be subject to more oxidative damage and be higher in lipid peroxides. Two health-related results are expected. One is a description of visual acuity in the avascular zone of the fovea. This may be useful for establishing treatment criteria for mascular disease. The other outcome will be better understanding of one of the key factors that is thought to protect the macula from damage.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY004911-06
Application #
3259530
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1983-09-30
Project End
1991-03-31
Budget Start
1989-07-01
Budget End
1991-03-31
Support Year
6
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Schepens Eye Research Institute
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02114
Delori, F C; Goger, D G; Hammond, B R et al. (2001) Macular pigment density measured by autofluorescence spectrometry: comparison with reflectometry and heterochromatic flicker photometry. J Opt Soc Am A Opt Image Sci Vis 18:1212-30
Hammond Jr, B R; Wooten, B R; Snodderly, D M (1998) Preservation of visual sensitivity of older subjects: association with macular pigment density. Invest Ophthalmol Vis Sci 39:397-406
Hammond Jr, B R; Wooten, B R; Snodderly, D M (1997) Density of the human crystalline lens is related to the macular pigment carotenoids, lutein and zeaxanthin. Optom Vis Sci 74:499-504
Crabtree, D V; Snodderly, D M; Adler, A J (1997) Retinyl palmitate in macaque retina-retinal pigment epithelium-choroid: distribution and correlation with age and vitamin E. Exp Eye Res 64:455-63
Snodderly, D M; Shen, B; Land, R I et al. (1997) Dietary manipulation of plasma carotenoid concentrations of squirrel monkeys (Saimiri sciureus). J Nutr 127:122-9
Hammond Jr, B R; Wooten, B R; Snodderly, D M (1997) Individual variations in the spatial profile of human macular pigment. J Opt Soc Am A Opt Image Sci Vis 14:1187-96
Hammond Jr, B R; Johnson, E J; Russell, R M et al. (1997) Dietary modification of human macular pigment density. Invest Ophthalmol Vis Sci 38:1795-801
Crabtree, D V; Adler, A J; Snodderly, D M (1996) Radial distribution of tocopherols in rhesus monkey retina and retinal pigment epithelium-choroid. Invest Ophthalmol Vis Sci 37:61-76
Crabtree, D V; Adler, A J; Snodderly, D M (1996) Vitamin E, retinyl palmitate, and protein in rhesus monkey retina and retinal pigment epithelium-choroid. Invest Ophthalmol Vis Sci 37:47-60
Hammond Jr, B R; Fuld, K; Snodderly, D M (1996) Iris color and macular pigment optical density. Exp Eye Res 62:293-7

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