I’ve have dry eyes and have used eye drops for years, usually 2 brands called Systane and Refresh Tears. They are the most highly reviewed and most expensive. Today at the store I read the lables for the first time on these 2 and several other cheaper brands. All listed their “active” ingredients at about 0.5%, with the rest being all PG.
Prices for 15ml bottles range from $5 to $12. So, that’s $333 to $800 per liter for PG !!!
Yeah so we can extrapolate from your implication, that you would be better off simply filling a small dropper bottle with PG and using that instead since PG does retain moisture and prevents bacteria breeding in it - those being the primary features of your average eye drops.
I wear contacts and use those drops occasionally, though since moving from Adelaide to Katoomba half a decade ago, I have found the misty mountain air doesn’t dry my contacts, really at all so I almost never feel the need for drops here.
In Adelaide - especially during summer - I’d be practically squirting that shit in my eyes all day long and they still remained dry/irritated.
I will happily be the guinea-pig next time I put-in my contacts, but I’m not wearing them today so there’s no need for moisture… though still, I could drip some PG in anyway…
I did look this up but I didn’t see it as 99.4% pg
Systane looks to be a combo of PEG 400 and PG with some boric acid and saline thrown in to balance the ph and preserve it from going off. I would suggest it is mostly water with PEG 400 and PG
Systane Ultra
Active ingredients: Polyethylene Glycol 400 0.4%, Propylene Glycol 0.3%
Inactive ingredients: Aminomethyl propanol, boric acid, hydroxypropyl guar, POLYQUAD® (polyquaternium-1) 0.001% preservative, potassium chloride, purified water, sodium chloride, sorbitol. May contain hydrochloric acid and/or sodium hydroxide to adjust pH.
Systane
Active Ingredients: Polyethylene Glycol 400 0.4%, Propylene Glycol 0.3%
Inactive Ingredients: Boric acid, calcium chloride, hydroxypropyl guar, magnesium chloride, polyquaternium-1 as a preservative, potassium chloride, purified water, sodium chloride, zinc chloride. May contain hydrochloric acid and/or sodium hydroxide to adjust pH.
Systane Balance
Active Ingredients: Propylene Glycol 0.6%
Inactive Ingredients: Boric acid, dimyristoyl phosphatidylglycerol, edetate disodium, hydroxypropyl guar, mineral oil, polyoxyl 40 stearate, POLYQUAD® (polyquaternium-1) 0.001% preservative, sorbitol, and purified water. May contain hydrochloric acid and/or sodium hydroxide to adjust pH.
I would not personally put straight PG or Peg 400 in my eye deliberately
So maybe stick a little PG in some saline solution - instead of pure PG - and you’ll have a rough DIY version for, almost nada.
I’ve had some brands of those drops that literally feel as thick as glycerine in my eye: like glue, it almost sticks my lids shut and I (again quite literally) have to peel gummy shit out my eyes after it’s warmed to eyeball temp and started evaporating away but I never remember which brand it is so can’t remember which drops to avoid, until I buy them again, and forget again…
It’s a viscous cycle.
I usually just use the contact lens soaking solution if I am home and want moister eyes, but that’s still only when the heater’s too high in winter causing them to dry out.
A bargain for piece of mind.