this told me TONS about dog eyes!

It may help to see actual photos of other dogs' eye issues along with their ultimate diagnoses...
Photo provided by Flickr
When you pull down the lower lid you may also see the third eye lid, also called the nictitating membrane, that will protrude over the bottom inner corner of the eye. The 3rd eyelid is not as easily protruded in the dog eye as in the cat. The 3rd eyelid is usually a pale pink or white color and has thin blood vessels on its surface. The 3rd eyelid is not visible in this photograph.
One sore, infected eye, with a pus-filled exudate. Take this dog right to the vet.
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As many dogs are skittish when someone tries to administer eyedrops, it is important to remain calm. After washing your hands and shaking the saline solution, sit down and put your dog between your legs with its back to you. Tilt your dog's head back and hold its eyelid open. (Alternatively, make a pouch of your dog's lower lid by slightly squeezing it together.) Place the eyedropper or bottle close to the outside of your dog's eye. Quickly squeeze the drops into the eye. Allow your dog to blink, which will help spread the solution over the eye. Also, administer the saline solution several times throughout the day, as it is washed away by tears. If your dog is prone to eye problems, consider adding one of the following to her diet:
Photo provided by FlickrThe following are signs that something may be wrong with one or both of your dog’s eyes:
Photo provided by Flickr4. If the dog’s eyelids are bruised or torn (usually from a fight or other trauma):
Photo provided by Flickr
Eye discharge is a common problem in dogs. Some types are completely normal, while others are associated with potentially serious health concerns. In order to determine when professional help is necessary, pet parents need to understand the various types of dog eye discharge and what each may mean. Let’s take a look at five common types of dog eye discharge and what you should do about them.Excessive eye watering () is associated with many different conditions that run the range from relatively to serious. Allergies, irritants, foreign material in the eye, anatomical abnormalities (e.g., prominent eyes or rolled in eyelids), blocked tear ducts, corneal wounds, and (increased eye pressure) are common causes of epiphora in dogs.Tears play an essential role in maintaining eye health. They provide oxygen and nourishment to the cornea (the clear layer of tissue at the front of the eye) and help remove any debris that might get trapped there. Tears normally drain through located at the inner corner of each eye, but sometimes a little bit of goop or crust will accumulate there. This material is made out of dried tears, oil, , dead cells, dust, etc. It is most evident in the morning and is often perfectly normal. The goop or crust should be easy to remove with a warm damp cloth, the eyes should not be red, and your dog should not exhibit any signs of eye discomfort (rubbing, squinting, blinking, and sensitivity to light). The amount of “sleep” a dog produces each night (or after long naps) should stay relatively constant. If you notice any worsening of your dog’s condition, make an appointment with your veterinarian.Light colored dogs often develop a reddish brown discoloration to the fur below the inner corner of their eyes. This occurs because tears contain a pigment called porphyrin that turns this reddish brown color upon prolonged exposure to air. In the absence of other problems, tear staining in this area is normal and is just a cosmetic concern. If you want to minimize your dog’s tear stains, try one or more of these solutions: Wipe the area a few times a day with a cloth dampened in warm water or an eye cleaning solution; keep the fur around your dog’s eyes trimmed short; and/or add an antibiotic-free nutritional supplement that reduces tear staining to your dog’s diet.If your dog has a relatively mild increase in tearing but his eyes look normal in all other respects and he doesn’t seem to be in any discomfort, it is reasonable to monitor the situation. Your dog may have simply received a face full of pollen or dust, and the increased tearing is working to solve the problem. But if the epiphora continues or your dog develops red, painful eyes or other types of eye discharge, make an appointment with your veterinarian.Dry eye (keratoconjunctivitis sicca or KCS) is a condition that usually develops when a dog’s immune system attacks and destroys the glands that produce tears. With tear production being less than normal, the body tries to compensate by making more mucus to lubricate the eyes. But mucus can’t replace all the functions of tears, so the eyes become red and painful and may develop ulcers and abnormal corneal pigmentation. Left untreated, KCS can result in severe discomfort and blindness.