Dry eye comes about two ways. If he does not have dry eye now he more likely never will.
Incidents resulting in dry eye:
1. Cherry eye removal. The proper procedure to repair a cherry eye is to insert it back where it belongs as it is part of the tear gland. Old school practice, which some vets still do because it is cheaper for the owner, is to remove it. This results in dry eye which will require a daily and lifetime of eye lubricant.
2. Hereditary - Some dogs are born with underdeveloped tear gland resulting in dry eye. Normally this is an issue for both eyes and not just one.
Symptoms: You can tell a dog has dry eye because the eye is normally dark in color and will have no shine to it. If not treated the dog will rub it. You may also see a lot of gunk or eye boogers as well.
Testing: A tear test is performed at your vet office showing the amount of tear production, if any.
Treatment: You treat dry eye with daily eye drops. The most common drop prescribed, and can only be purchased from a vet, is Cyclosporine. This is not cheap but sometimes required at the beginining. Cyclosporine is given two to three times a day.
After a round of cylosporine or Optimmune (a blend) you can use Optixcare eye Lubricant + Hyaluron (Amazon.com has great prices) during the day and at night GenTeal PM Ointment Lubricant (Walmart or local pharmacy). Medication is a must in order to keep your dog comfortable.
Every dog is different as for how often to apply the eye medication. If you notice the eye getting crusty you need to up your number of times you apply daily.
Not treating a dry daily daily is painful and can result if blindness.