The eyes of the olms.

The experiments of the Austrian biologist Paul Kammerer to breed eyes in blind olms is probably one of the most notable manifesations of Lamarckian thinking and research at the beginning of the 20th century. If living in the environment of the dark caves in the Slovenian Kraijna for thousands of years has reduced the eyes of the olms until they nearly disappeared, then is it possible to influence the development in the other direction and speed it up? Will a transformed milieux or media (in a Lamarckian sense) conduct olms to vision, to the mysteries of light? Kammerer's legendary skill in taking care of animals (especially amphibians), the highly modern research environment of an institution unique in whole Europe and America at that time (the Biologische Versuchsanstalt Wien), years of experimental crossings, and, finally, the convergence of biological media and technical media (for example media of development in photography), provided the opportunity for Kammerer to succeed. The olm experiments are part of an elaborate research program of the Viennese Versuchsanstalt and its facilities that assume the environment of animals to be the critical point in developmental, hereditary, and evolutionary research. Theoretically Kammerer's olms ask questions about vision in general and its organ, the eye.

Motion perception deficits in albino ferrets (Mustela putorius furo).

Albino ferrets contrary to their pigmented conspecifics show no optokinetic nystagmus. Therefore, in this study motion perception was compared between pigmented and albino ferrets (Mustela putorius furo) trained to discriminate between coherently moving random dot patterns and dynamic noise stimuli in a two-alternative forced choice task. Fully coherently versus incoherently moving patterns could be distinguished by ferrets of both phenotypes. Motion coherence thresholds, however, were significantly higher in albinos. These results indicate that albino ferrets are not motion blind as could be expected from their total lack of optokinetic reactions. However, they are severely impaired in global motion perception.

Unilateral ocular subalbinism in a laboratory Beagle dog.

Blue discoloration of the iris was found in the left eye of a male laboratory Beagle dog, which had a normal tricolor coat and clinically showed no visual impairment. Ophthalmoscopically, the affected eye revealed red-colored tigroid fundus, in which no tapetum was present. The retinal vasculature and the optic disc showed no noticeable changes. Histopathologically, in the left eye melanocytes had extremely few melanin granules in the anterior segment, including the anterior border layer, in the stroma and sphincter muscle of the iris and in the stroma of the ciliary body and choroid. However, the posterior pigment epithelium of the iris, the pigment epithelium of the ciliary body and the retinal pigment epithelium showed normal pigmentation. The tapetal elements were completely absent. Number and distribution of the S-100 protein-positive melanocytes with or without melanin granules in the iris, ciliary body and choroid of the left eye were similar to those of the normal right eye. Ultrastructurally, melanocytes in the anterior segment of the affected iris possessed no or few melanosomes which were incompletely melanized. In the right eye, no abnormal features were observed. Based on these results, the present case was diagnosed as unilateral ocular subalbinism with tapetal aplasia in a Beagle dog.