Light damage is an important and well establish model to study degenerative mechanism in the retina. So far this light damage assay has been used in high light intensity directly leading to photoreceptor damage. In order to study involvement of supportive tissues we examined light damage at the lower threshold levels. For this purpose mice were previously adapted to dark conditions followed by an exposure to a light intensity of 8000 lux for 30 minutes.

After 3 days tunnel assays revealed few signals of apoptosis and after 9 days histology showed a variety of different patterns in the retina of mice exposed to 8000 lux. Changes in retinal structure were detected close to the optic nerve close to temporal area. These changes comprise thickening of the outer nuclear layer whereas others regions show loss of nuclei in the outer nuclear layer.

The complex pattern of retinal aberrations after threshold light damage suggests much more signaling pathways involved. Study of the complexity of these pathways will lead to the identification of new degenerative mechanisms.