Salt poisoning blindness in wistar rat, rabbit, and pig

Abstract

The objective of this study was to determine the ocular changes leading to blindness following different salt concentration consumption in Wistar rats. Test groups consumed 1, 2, 3, 3.5, or 4% salt concentration respectively as potable water, while the control group used tap water. Ophthalmic examinations with a slit-lamp and fundus camera were performed. Lack of eye response to light and manual stimuli were considered as blindness criteria. Similar experimental conditions were performed in pigs and rabbits. Short duration consumption of 1 or 2% salt concentrations did not produce any detectable ocular signs, whereas long duration consumption of 2% salt concentration induced prominent ocular signs. After 3–4 days of consuming 3% and higher salt concentrations, retinal and vitreous hemorrhages, posterior vitreous detachment PVD, and retinal detachment were observed. The following ocular changes included conjunctivital injection, cornea and lens opacities, swelling of the optic disc, blindness, vitreous collapse, and finally phthisis bulbi. Salt poisoning led to hypernatremia and hyperosmolarity. Due to hyperosmolarity, the vitreous lost some of its fluid contents and vitreous shrinkage resulted in vascular damage, retinal and vitreous hemorrhage, PVD, and retinal detachment. In addition, conjunctivitis, corneal and lens opacities, swelling of the optic disc, blindness, vitreous collapse, and finally phthisis bulbi was evident.