Elektroretinographische Messung der Spektralsensitivität von Albinoaugen bei direkter und diaskleraler Belichtung

Summary

The relative spectral sensitivity of the dark adapted rabbit eye was measured by means of the electroretinogram. As already reported this is modified in albino rabbits by the reflection of blood behind the visual cells.

By varying the size of the stimulus area it was shown that these modifications result from indirect stimulation by light diffusely reflected from the fundus. The lack of alteration of the spectral sensitivity by the Soret band of haemoglobin absorption is probably due to the fact that the light reflected from the fundus in the blue part of the spectrum is subthreshold. Therefore, the retinal response in the short wavelength part of the spectrum is determined entirely by the light falling directly on the retina and not by reflected light.

However, with diascleral illumination the Soret band was reflected in the sensitivity curve since under these conditions the light reaching the photoreceptors must pass through a blood filter.

In discussing the modifications of spectral sensitivity due to diascleral stimulation, such factors as blood and other tissue absorption and scattering of light in the sclera (which affects the size of the retinal area stimulated) are considered.