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.