Getting old isn't for sissies. That's true for us as well as our pets. As we age, we're likely to find that our bodies just don't work the way they used to. But the ills of aging aren't necessarily the same in humans as in dogs and cats.

Eye diseases are among the most commonly seen problems in older dogs and cats.

You may notice a bluish haze in your pet's eyes. It isn't cataracts, as is often suspected, but the result of a normal aging of the lens. The condition, called lenticular sclerosis or nuclear sclerosis, usually doesn't affect vision or require any treatment.

Dogs do get cataracts, but they show up as cloudy spots on the normally transparent lens of the eye. They look like a milky gray film behind the pupil. Cataracts may start to appear when a dog is 6 to 8 years old. Unlike lenticular sclerosis, cataracts can eventually lead to blindness.

Because they rely more on scent than sight, however, dogs with cataracts can get around fairly well by using their noses — as long as you don't move the furniture. If your dog's cataracts are so bad that he's running into things, ask your veterinarian about cataract surgery.

Older cats rarely develop cataracts. They are more likely to suffer vision loss from retinal diseases, uveitis (a painful inflammation of certain eye structures) or glaucoma. Like dogs, cats adapt fairly well to vision loss. They compensate by relying more on their hearing or their whiskers.

Other age-related vision problems, such as keratoconjunctivitis sicca (better known as dry eye), require aggressive treatment. Tears, which are produced by the lacrimal glands, lubricate, protect and cleanse the eye. Tear production tends to decrease with age. If that happens, the eye becomes dry and irritated and starts to produce more mucus, causing a goopy discharge. Dry eyes are itchy, and dogs may scratch at them or rub them on the carpet in an attempt to relieve the itch. Dogs with dry eye are also more likely to develop corneal ulcers.

Dry eye is diagnosed with a tear test. The veterinarian places a tiny paper strip at the inner corner of the eye, where the tears pool, and holds it there for one minute to see how much of the strip becomes wetted with tears. If the result indicates that tear production is below normal, the animal likely has dry eye. Dry eye is less common in cats than in dogs.

Depending on the condition of the eye, your vet may prescribe artificial tears, antibiotic eyedrops or an immunosuppressant drug that stimulates tear production. This helps to keep the dog comfortable and the cornea healthy.

Glaucoma is an increase in pressure within the eye. It can develop quickly and is extremely painful. If your pet is squinting and its eye is tearing and feels harder than normal, consider it an emergency. A dog or cat with an acute case of glaucoma can lose his eyesight within 48 hours if the condition isn't treated immediately.

Take your dog to the vet for an eye exam anytime you notice the following signs:

• Redness

• Cloudiness

• Discharge

• Opaque or whitish film over the eye

• Tearing, squinting, pawing at the eye or other signs of pain

• Sensitivity to light

• An unusually soft or hard eye

• A swollen, crusty or itchy eyelid

• A bulging or sunken eye

If you notice that your pet's vision is not as keen as it used to be, don't simply chalk it up to old age. Oftentimes, medication or other treatment can help, especially if the problem is diagnosed early.