Ok thank you,
An eye closed or squinting is a symptom of infection and/or inflammation. It may be seen with diseases of the external eyelids, third eyelid, conjunctiva, cornea. It may also occur with inflammation of the structures inside the eye, with glaucoma (high pressure within the eye), or something foreign stuck in the eye.
This is a situation that requires a vet.
A vet may need to do some test such as: tear test to measure tear production, to check for ulcers in the cornea, a tonometry test (measures pressure in the eye).
Treatment will depend on the underlying cause the tests show.
From Anti-inflammatory medications, topical corticosteroids, antibiotic or antiviral eye medication, lubricant eye drops, wet compresses.
I wish I could tell you exactly what is causing the eye trauma, but as I stated above there are a couple of thing that could causing it, and proper test from the vet are the only way to diagnose it. I strongly advise a vet visit because many eye diseases can leave the poor animal blind.
Keep the eye clean as it sounds like your doing. You can use warm water dampened cotton balls or Q tips or even plain saline. Do not put human eye drops like visine in it. That will cause damage.
Please let me know if you need any further help with this.