Martijn J. Kanis

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PURPOSE To separately measure the optical densities of lutein (L) and zeaxanthin (Z) in the human retina in vivo. L and Z are the basic constituents of the macular pigment (MP). METHODS Spectral fundus reflectance was measured in 23 subjects (group 1) at 0 degrees , 1 degrees , 2 degrees , 4 degrees , and 8 degrees eccentricity with a modified macular(More)
Macular pigment (MP) and melanin possibly protect the macular area by absorbing blue light and acting as antioxidants. Because little is known about the interocular correlation of melanin, we determined its optical density (MOD) in both eyes of healthy subjects using fundus reflectometry. The measuring method also provided optical densities of MP (MPOD). In(More)
Light is the signal that entrains the biological clock in humans to the 24-hour external time. Recently, it has been shown that short wavelengths play a key role in this process. In the present study, we describe a procedure to measure, objectively and in a quick way, the spectral composition of the light reaching the retina in vivo. The instruments(More)
PURPOSE To establish the relation between AMD stage and a quantitative measure for the integrity of foveal cone photoreceptors related to the optical Stiles-Crawford effect. METHODS Fifty-six AMD eyes and 57 control eyes were included in the final analysis. AMD was graded in accordance with the International Classification System into five mutually(More)
The protective effect of macular pigment (MP) and melanin against age-related macular degeneration (AMD) is still controversial from cross-sectional studies. In an attempt to clarify this issue, we performed a population-based longitudinal study. MP optical density (MPOD) and melanin optical density (MOD) data were collected during the second follow-up(More)
To test whether foveal cone photoreceptors are impaired in primary open-angle glaucoma (POAG). Nineteen POAG eyes with central glaucomatous visual field defects, and 34 age-matched control eyes were included. Fundus reflectometry, together with a model fit procedure, provided information on a set of parameters: lens optical density, macular pigment optical(More)
Directional and nondirectional spectral reflection data from 0, 1, 2, 4, and 8 deg eccentricity, and the optic disk, were analyzed from 400 to 950 nm with an existing optical reflection model. The optical model, developed for the fovea, appeared to be also suitable for more eccentric locations. The optical densities of melanin and of the macular pigments(More)
A 68-year-old man who had undergone two penetrating keratoplasties of his left eye was admitted with early corneal graft failure. Culture of the anterior chamber fluid yielded Paracoccus yeei, a nonfermentative gram-negative bacillus which thus far had only been implicated in ocular disease by means of PCR and 16S rRNA gene sequencing directly on patient(More)