Résumé
Retinal function depends on light trapping. However, continuous exposure to light may cause damage to the highly vulnerable retinal structure. This study aimed to investigate the possible histological alterations that might occur in the retinal neurons as a result of continuous exposure to fluorescent light in adult male albino rats. Ten healthy adult male albino rats were equally divided into two groups: a control group and a light-exposed group. Rats of control group were kept in 12 h light/1 2 h dark for 12 weeks. Rats of light-exposed group were put in top-opened cages illuminated by white fluorescent bulbs continuously for 1 week and then were kept in 12 h light/12 h dark for the following 11 weeks. The retina was extirpated and processed for examination by light and electron microscopy. The thickness of outer nuclear, inner nuclear, outer plexiform, and inner plexiform layers was estimated morphometrically and was statistically analyzed. Fluorescent light-exposed neural retina revealed that photoreceptor outer segments were markedly disorganized and inner segments were short and less condensed. Outer nuclear layer containeo few photoreceptors with marked intercellular spaces. Inner nuclear layer showed wide spaces between its neurons, with some of them having shrunken nuclei and others having disintegrated nuclei. Muller cells with deeply stained bodies and processes were seen in inner and outer nuclear layers. Many ectopic neurons were detected in the inner plexiform layer. Ganglion cell layer mostly contained deeply stained glial cells and few ganglion neurons. Nerve fiber layer showed an apparent increase in thickness. The estimated and analyzed thickness of the outer nuclear, inner nuclear, outer plexiform, and inner plexiform layers confirmed the results. Continuous exposure to fluorescent light triggered retinal remodeling, including neuronal loss, reactive gliosis with neuronal and glial cells migration. This may lead to visual impairment