Retinal Damage and Sensitivity Loss of A Light-Sensitive Crustacean Compound Eye ( Cirolana Borealis ): Electron Microscopy and Electrophysiology

Abstract

The compound eye of the deep-water-living crustacean Cirolana borealis has been exposed to measured amounts of white light, and the effects have been analysed by electron microscopy and electrophysiology (ERG). The threshold for damage of the retinula cells lies between 117 lx (0·47Wm−2) and 1250 lx (4·9 Wm−2). With daylight exposures of more than 70 W m−2, there is severe structural derangement and the amplitude of the electroretinogram (ERG) is abolished. No recovery of the retinula cell organization or of the ERG occurs after daylight exposure and a dark period of up to 5 days. A novel type of photoreceptor membrane shedding is described for both dark-adapted and light-exposed eyes. Hence, morphologically and functionally, the Cirolana eye is strictly adapted to a dim-light environment and is destroyed by too intense illumination.