Ocular effects of water from acidic lakes: an experimental study.

The purpose of this experimental study was to determine the effects on the conjunctiva and cornea of eyes exposed to water from acidic lakes in comparison with water from lakes having a nearly neutral pH. One eye each of 190 rabbits was exposed to an experimental sample of water having a pH of 5.18, 5.04, 4.70 or 4.50. The other eye of each rabbit was simultaneously exposed to a control sample of water having a pH of 6.40 or 6.21. The water was continuously instilled for 15 minutes every day for 7 days. Observations were made daily. The two eyes of each rabbit were compared for conjunctival congestion, corneal staining with fluorescent dye, the granulocyte count and osmolarity of the tears, bacteriologic findings in conjunctival swabs, corneal cell damage, corneal thickness and ultrastructural features of the corneal epithelium. Although some of the rabbits showed a difference of reaction in the two eyes, the majority showed similar reactions to water from the acidic and nearly neutral lakes.