To the Editor:
The papers by Behrendt and his collaborators1,2 are of profound interest and prompt the following comments. When Behrendt and Duane write that "it is no longer necessary to investigate single, discrete, point-sized areas of the fundus employing small pencils of light and photometric measurement of the reflected energy to obtain satisfactory spectral reflectance analyses," one may be permitted to observe that if photospectrography of the fundus was possible some ten years ago (Weale3,4), spectrophotography should be possible today. The belief that blue light of wavelength 477 nm "does not penetrate beyond the neurofibral layer" may be thought a little too categorical on the following grounds: (1) As such light is seen subjectively, it must penetrate this layer. (2) As such light can be used to detect photochemical reactions photographically4 and photoelectrically (Ripps and Weale5), the odds are that it penetrates this layer. Moreover,
Weale RA. FUNDUS PHOTOGRAPHY. Arch Ophthalmol. 1966;76(3):467. doi:10.1001/archopht.1966.03850010469040
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