Cloudy Eyes

By Dr. Donald Consla, Lead Wellness Veterinarian

As dogs and cats age they can start to develop changes in their eyes just like people. One of the most common misconceptions I observe in day-to-day practice is that all changes in the eyes are synonymous with cataracts. This is not always the case and sometimes, the changes pet owners are seeing are normal. Let’s talk about the age-related changes first. This change is called nuclear sclerosis. The “nuclear” portion refers to the center of the lens of the eye and “sclerosis” means scarring. Essentially, as the eye ages, the new fibers of the lens build around the old fibers pushing them inward. Over time these fibers build up like the layers of an onion and become more dense. We typically start to see this change around 7-8 years of age in dogs and cats. Owners will often notice that when light hits their pet’s eye, the pupil (where the lens lives) has a hazy blue or pearl-like appearance. This appearance is from the light scattering off the now denser lens. This is a normal change. In humans, this change may cause some difficulty seeing up close. This may happen in our four-legged friends as well but overall it does not cause any significant changes to vision.

While nuclear sclerosis is normal, there are many disease processes that can cause the eyes to appear cloudy. Many of these conditions are painful and you may notice redness of the eye, discharge or squinting. If you notice any of these clinical signs, you should seek veterinary care immediately. We can classify these into three main anatomic areas: the cornea, the anterior chamber or uvea and the lens. The cornea is the clear outer surface of the eye. Ulcers or scratches, viral infections, glaucoma, dry eye and mineral/fatty deposits are a few examples of conditions that would cause this tissue to become cloudy. Many of these conditions are painful and seem to start all of a sudden.

The next area is the anterior chamber and uvea. The anterior chamber is the fluid-filled space between the cornea and the lens. The uvea is the iris or colored part of the eye (a muscle that controls the size of the pupil). Any inflammation or infection of this part of the eye will cause cloudiness, discomfort or even what looks like blood in the eye. Like many of the corneal lesions, disease in this area requires urgent veterinary care.

We have talked about nuclear sclerosis but the other most common change to the lens is cataracts. A cataract is a mineralization of the lens (versus scarring of the lens). It can be difficult to tell the difference from looking at the eye externally but when using an ophthalmoscope, it is clear. With nuclear sclerosis, we are still able to see through the lens to the back of the eye. With a cataract, we are unable to see through any mineralized portion of the lens. Cataracts can happen as dogs and cats age but also from various disease processes such as diabetes, inflection or inflammation in the eye.

Your veterinarian can help distinguish between any of these changes and if you notice any redness, discharge or squinting you should seek veterinary care immediately.

Schedule a senior wellness exam for your pet at our Clinic by calling 412.847.7004 or email

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