What is lenticular sclerosis?
Lenticular sclerosis or nuclear sclerosis is the medical term for a bluish transparent haze that develops in the lens of the eye in middle-aged to senior dogs. This is considered a normal change in the lens associated with aging, and is observed as a cloudiness or bluish discoloration on the pupil.
Vision does not appear to be significantly affected in dogs diagnosed with lenticular sclerosis. This condition is not the same as cataracts.
Cataracts are white and opaque and represent a change in the ability of light to penetrate to the retina. Cataracts cause diminished vision. Cataracts and lenticular sclerosis are two of the most common eye problems seen in dogs over the age of nine. Some estimates show the prevalence of lenticular sclerosis or cataracts at 50% in dogs over nine years of age and 100% in dogs over the age of thirteen.
Lenticular sclerosis typically occurs bilaterally (in both eyes) and symmetrically in dogs. Lenticular sclerosis appears as an evenly gray, rounded opacity (cloudiness) in the center of the lens, and is most easily observed when the pupil is dilated. The opacity is often more dramatic when viewed from the side rather than from the front. When the eye is examined with an ophthalmoscope, the retina and fundus (back of the eye) can still be seen through the sclerotic lens.
While the exact mechanism is poorly understood, it appears that the lens gradually becomes harder with age. Lens fibers are produced throughout life, but the lens does not become bigger. It is believed that, as the central lens is compressed by new fibers deposited on the outer rings of the lens, the compression leads to hardening and lens becomes opaque.
Home / Pet Care News and Blog / What Causes a Blue Eye in Dogs?Your Kitchener Vet | © 2022 Kingsdale Animal Hospital chevron-downtwitter-squarefacebook-squaretwitterfacebookenvelopelinkedinxinginstagrampaper-planepinterest-pwhatsappcrossmenuarrow-3-down-bottomArrow-1-Up-Topdelete-disabled-crossmenu-burger-square6arrow-location-directionMobileemail-letter-square
Diseases that cause blue eyes in dogs
We should state that the first reason your dog has blue eyes might not be a discoloration. While most dogs have an eye color which is some shade of brown, it is possible for certain breeds to have blue eyes throughout their lifetime. One of the most common blue-eyed dog breeds is the Siberian Husky.
Another curious fact about blue eyes in dogs is that many puppies will have blue eyes when they first open them. This then changed as they age into adolescence, becoming their natural color in a few months time. If you look closely, you can often see the flecks of color appear gradually. Its important to know this is a natural process and not a sign of disease.
If the dogs eye is turning blue unnaturally, then there are not many possible causes. Generally, there are two reason why your dogs eyes have turned blue. They are:
There are other diseases which can lead to eyes changing color. They include cataracts, corneal dystrophy, glaucoma or uveitis. With these diseases, the eyes are not likely to turn blue. Instead, they will grow cloudy or achieve a whitish hue. It is possible there is a blue tinge, but it may depend on the light and original eye color.
Among the many eye diseases which can affect dogs, not many can cause the eye to appear blue. With interstitial keratitis, the cause of the color change is the inflammation of the cornea. Interstitial means the inflammation is occurring between the cells of the cornea. The result is a whitish film which appears over the eye. The cause is the infectious canine hepatitis virus, something we will discuss further in the next section.
With interstitial keratitis in dogs, you will see the dog developing the white film over their eye. This film can look blue, but to varying degrees. This will occur about 10 days after the dog has been exposed to the virus and become infected. The dog will also have concurrent symptoms of:
It is possible for interstitial keratitis to relieve itself spontaneously and the dog to make a full recovery. However, it is also possible the dog will maintain the blue color for the rest of their lives.
This variation of hepatitis strain is caused by a virus, specifically by the canine adenovirus type 1 (CAV-1). Although fortunately not very common, it is incredibly contagious. The main reason it is not widespread is due to the hard work of canine vaccination strategists. As part of a puppys initial vaccinations and their yearly boosters, a vaccination against CAV-1 is given. This is why the highest percentages of cases occur in dogs under the age of one year.
Once the virus is in the dogs system, it reproduces within the bodys tissues. This means that it can then be eliminated from the body via various secretions. These include blood, nasal discharge, saliva, feces and urine. This is why it is highly contagious, especially in dogs which spend a lot of time together. Even when the dog recovers, their urine can still be contagious between 9 months and a year. The disease usually enters through the mouth or nostrils. It will then spread to the liver and kidneys.
Individual dogs respond in various ways, depending on a number of factors. Some dogs will not even display symptoms, others can die in a matter of hours. There are many variations between these two extremes, but we always need to be careful of symptoms. The change in color of the eye is due to edema, i.e. liquid filling up between the layers of cells. The eyes can be given a whitish coloration, but the eye turning blue can also occur.
Other symptoms of CAV-1 include:
Even when a dog recovers, the blue or white colorations over the eye might remain. It will depend on the acuteness of the symptoms and the progression of the infection. More commonly, the blue color will disappear afer a few days of its own accord.
Nuclear sclerosis in dogs is a physiological degeneration which can occur in all mammals, including human beings. This means it is a normal consequence of age. In canines it is also known as lenticular sclerosis as it forms a blueish haze over the lens of the eye. The look is quite similar to that of the beginning of a cataract, but it is imperative we distinguish between the two.
The reason for an appropriate diagnosis is due to potential loss of vision. With nuclear sclerosis, the haze over the eye doesnt necessarily affect the dogs vision. With cataracts, this can occur and surgical intervention may be required. Lenticular sclerosis can affect vision, but only if the lens grows very dense, something not common in dogs.
