Question on using CS as eye drop

My child suffers from eye allergies this whole summer. The symptoms is forcefully blinking eyes. Later we learned that he is very allergic to dust mite, weeds/grass/tree pollen of the season. I add one drop of CS to Sea Salt water and rince his nose am and pm and his sniff improves a lot. But his eye blinking persists with the use of Zanitor eye drop. My question are can I use CS (I have mesosilver) as eye drop for him? Is 20mmp too strong, and how much I need to dilute? Also for both nose and eye use, is it safe to use CS for a long term? I don't want him to be dependent on CS either, but if I stopped, his sniff would come back. Thank you so much for your advice and help! (We already tried bed encasement, hardwood floor and air purifier)