A very diluted copper sulfate solution was used in eye drops to clarify vision and reduce sensitivity to light. 0.15 mg/ml concentration.
In 1 ml is 20 drops. 20 / .15 = 133. So, one drop of copper sulfate per 133 drops of distilled water. There are 1182 drops in a 2 oz. bottle. 1182/133 = 9 drops. So, 9 drops of our 1 mg per drop copper sulfate goes into a 2 oz. bottle, and fill the rest with distilled water.
Historical information on using copper sulfate for eye conditions:
“Verdigris and blue vitriol (copper sulfate) were used, among other things, in remedies for eye ailments such as bloodshot eyes, inflamed or “bleary” eyes, “fat in the eyes” (trachoma?), and cataracts.”