Cataracts Vs. Nuclear Sclerosis

Cataracts Versus Nuclear Sclerosis

Emily Conway, BVMS, MS, MRCVS, DACVO

Cloudy eyes can be a major concern for pet owners, especially since cataracts are an important cause of vision impairment in pets. Cataracts and Nuclear sclerosis are the most common causes of clouding of the lens that may be noted by pet owners, but there is sometimes confusion over which condition a pet is affected by.

A cataract is an opacity of the lens; cataracts can be congenital, secondary to inflammation, metabolic, traumatic, or age-related. The degree of visual disturbance relates to how much of the lens is affected – an incipient cataract can affect 10-15%of the lens and may not cause any visual impairment. A mature cataract, however, affects 100% of the lens and causes significant visual impairment. Cataracts can lead to the development of inflammation inside the eyes, which can lead to the development of serious complications, like glaucoma. Early evaluation of cataracts may help prevent complications long term.

Nuclear sclerosis, on the other hand, is an age-related change to the lens. Nuclear sclerosis is often noted after 8-10 years of age in dogs and cats. The fibers of the lens are produced throughout life and over time the nucleus of the lens (the center of the lens) become compressed. As a result, the nucleus of the lens is denser and can appear cloudy. In contrast to cataracts however, nuclear sclerosis is not thought to cause any significant vision impairment in our pets.

If you are concerned that your pet may have cataracts or nuclear sclerosis, they can be differentiated with a thorough ophthalmic exam. To fully evaluate the lens, your veterinarian or a veterinary ophthalmologist may dilate the pupils with a medicated eye drop. Although people are sometimes sensitive to light after dilation, pets tolerate being dilated very well with an eye exam.

If you have any concerns about your pet’s vision or are concerned that their eyes are cloudy, it is always a good idea to have their eyes evaluated!