Most eye drop solutions are nothing more than saline solution. Buy an eye dropper and fill it with saline solution (that costs 99 cents a pint on sale) and use that when your eyes are dry. Much better than paying $3-$5 for 1 ounce of eye drops!
John and Sharon must be insiders to the eyecare industry. Indoctrinated! "Gotta buy our industry's drops and solutions--it's the ONLY way!"
I did exactly what Kathy suggests for years and years, not to save money, but rather because most eyedrops--as in John's example--contain bizarre chemicals. I never had a problem. (Not to mention taking a shower every day, which gets water in the eye... oh, and swimming in pools, lakes, rivers and oceans, and even getting gnats right in my eye, just like you have.)
Now, I've done this web search for a recipe to make my own saline because I'm having a new problem--my eyes are becoming sensitive in an allergic sense to all the chemicals that are in eyedrops and saline solutions, and I need to wet my eyes with something because I'm post-Lasik.
I am getting the impression that some readers may be thinking about sterility of any solution as a lasting property. Yes, eye drops are sterile when you purchase and first open them but that can quickly change if the tip touches your eye. Most of these solutions would have some form of preservative to not spoil.
I used to get sore eyes from cats (well not from the cats directly - the eyes were mine) and home-made saline solution with a not particularly precise amount of salt in boiled water (that had of course cooled before I put it to my eyes) worked wonders every time. It doesn't need to be that precise to work great for allergic soothing.
I used this for a science fair project and it worked fine. 1/4 teaspoon iodized salt boiled into 1 cup of tap water.