artificial tears: can they cause chemical burn when used improperly?

2 weeks ago, I woke up at 3am w/dry eye. I used a vial of Bion
artificial tears that came from a foil package of 4. I realized the
next day that I should have thrown that package away -- you are
supposed to use all 4 vials in the package w/in 4 days, and mine was 2
weeks old!!

There is a apparently a pH-stabilizing chemical that evaporates after
4 days.

See: http://www.alconlabs.com/ca_en/eo/conditions/FAQ-dryeye.jhtml

I am concerned that using the vial after the cut-off time could have
made the vial highly alkali and burned my eyes. My eyes were irritated
for 2 days afterwards, then seemed to be ok. This was 2 weeks ago. Now
I have a lot of eye pain, blood vessels in my cornea, increased
floaters, decreased vision, and other eye problems.

However, what complicates matters is that I also had an allergic
reaction to an anesthetic the doctor put in my eye April 2nd (see my
post on discoloration of pigment around my pupil, from May 1). I am
trying to eliminate the artificial tears as a possible cause of my
problems; if anyone knows about chemistry and the eye, can you please
respond?

Here are the ingredients of the artificial tears:

Active Ingredients: Duasorb, a water soluble polymeric system
containing:: Dextran 70 0.1% (Lubricant), Hydroxypropyl
Methylcellulose 2910 0.3% (Lubricant)

Inactive Ingredients: Calcium Chloride, Magnesium Chloride, Potassium
Chloride, Purified Water, Sodium Bicarbonate, Sodium Chloride, Zinc
Chloride, Hydrochloric Acid and/or Sodium Hydroxide and/or Carbon
Dioxide to adjust pH

Thanks.