Eye problems are common in both dogs and cats.  Below is not a comprehensive list but some of the more common problems we see, when they show up, what pets are affected, and some of the signs to watch for.

These can range from small scratches on the eye to deep ulcers. They are usually caused by trauma, but can also be caused by irritation from soap during bathing, chemical burns, dry eye, or infections.  Both dogs and cats can get corneal ulcers, and symptoms include:

• Red eyes
• Increased watering from the eyes, discharge buidup at the corner of the eyes
  
• Squinting the eyes or holding the eye shut
• Pawing at the eyes or face
  
• Light sensitivity

Corneal ulcers are easy to diagnose with a fluorescein stain.  This stain will stick to damaged corneal epithelium and show up bright green under a special light.  Treatment includes frequent eye drops for most ulcers, but deep ones may need surgery to save the eye.

KCS is an immune-mediated process that causes the lacrimal gland in the eye to stop producing tears.  It is more common in dogs.  When there is no tear production, the eyes become dry and this leads to mucoid discharge buildup in the corners of the eyes, squinting, and can predispose the dog to corneal ulcers.  Dogs that are taking certain antibiotics can also be predisposed to developing KCS.  Treatment initially consists of medication to stimulate tear production.  If this does not work, either artificial tears are used for the rest of the pet's life, or a surgery can be performed to move a salivary duct up to the eye to create new tears for the dog.

These are very common in middle aged to older pets, and occur when the lens develops an opacity that causes it to become cloudy.  Sometimes people confuse cataracts with lenticular sclerosis, which is a normal aging change that the lens goes through once a pet reaches about 6-7 years of age.  With lenticular sclerosis, there is a slight cloudy appearance to the lens but this does not interfere with vision.  A veterinarian can easily tell the difference between these two conditions when evaluating the eyes with a scope.  True cataracts can form secondary to inflammation in the eye, because of genetic predispositions to forming them, or from age related changes in the eye.  Diabetic dogs will always develop some degree of cataracts even if glucose regulation is tight.

*note - sudden onset of cataracts in dogs always warrants a blood sugar check for diabetes*

Cataracts will progress until your pet no longer has vision in the affected eye.  Some dogs do very well with no vision, but cataracts can also cause other problems in the eye.  If the lens moves out of position, which happens more frequently in lenses with cataracts, this predisposes your pet to glaucoma.  Very mature cataracts can actually start dissolving in the eye, which causes dramatic inflammation and pain.  There is an option for cataract surgery in dogs and cats, and referral to the ophthalmologist is needed to evaluate if your pet is a good candidate for cataract surgery.

This is an inherited condition in dogs where the eyelids are not in the proper position, instead rolling into the eye so that the eyelashes are rubbing against the eye.  This creates irritation on the cornea and sclera, and can cause ulcers, increased eye discharge, or may have no symptoms at all.  Surgical correction is needed if the pet is bothered by the entropion.

This is an inherited condition in dogs where the eyelids are not in the proper position, instead rolling outwards away from the eye.  This can cause chronic conjunctivitis, dry eyes, and irritation.  Surgical correction is needed if the pet is bothered by the ectropion.

This is the lay term for protrusion of the nictitans gland, or the third eyelid gland.  Certain breeds are predisposed to this condition.  Once protruding, the gland will become swollen and irritated, which led to its name "cherry eye" - the gland looks like a red swollen cherry at the corner of the eye.  Surgery is needed to replace the gland and tack it back into place with sutures.  Removing the gland is not recommended because it helps to supply the eye with tears and can lead to dry eye if it is taken out. 

Just as this condition is serious in people, often it is an emergency situation in dogs.  Some breeds are predisposed to glaucoma, but it is also common in dogs with cataracts, especially if the lens luxates and blocks the flow of fluid in the eye.  Symptoms include:

• Red eye with swollen vessels in the sclera (white of the eye)
  
• Protruding or bulging eye (one looks larger than the other)
• Pawing at the face or eyes
• Squinting
• Light sensitivity

Diagnosing glaucoma is quick and easy and can be done with an instrument called a tonopen, which reads pressures in the eye.  Normal eye pressures for dogs are 10-20.  When dogs are first diagnosed with glaucoma, often times their eye pressures are 40 or higher.  This is very painful and if left untreated will cause permanent blindness.  Treatment is aimed at decreasing pressure in the eye, usually through eye medications.  We often refer pets to the ophthalmologist after stabilizing the eye.  If medical treatment does not work, then often enucleation (removal of the affected eye) is necessary to prevent pain.

This is a condition in middle aged to older dogs that results in atrophy (or wasting away) of the retina, the lining on the back of the eyes responsible for conducting light so that you can perceive vision.  The first symptom is usually poor vision at night with an increased eye shine, followed by a steady decline in vision until the pet is blind.  Certain dog breeds are predisposed, and a thorough retinal yearly exam should help identify those pets afflicted with PRA.  There is no treatment, but antioxidant supplementation is supposed to help slow the progression of PRA.