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Nucelear Sclerosis Old Dog with Hazy Eyes

Old Dog with Hazy Eyes

An old dog with hazy eyes has likely developed a condition that is known as nuclear sclerosis. Also known as lenticular sclerosis, nuclear sclerosis is considered a completely normal sign of aging. Most dog owners describe their old dog with hazy eyes as having developed a bluish transparent tint of the pupil which differs from its former jet black color. Fortunately, this change in the lenses of the dog's eyes related to aging doesn't typically affect a dog’s vision. If you notice though any changes in the way your dog sees, consult with your vet at once. You may be dealing with some other type of eye disorder that needs veterinary attention.


Dilated dog pupil showing cloudiness of nuclear sclerosis.

Old Dog with Hazy Eyes

Nuclear sclerosis is considered a normal, slowly developing change associated with aging. To better understand this condition, it helps to become better accustomed with the dog's lens.

The lens are a transparent structure made primarily of water and proteins, which along with the cornea, are responsible for helping the eye focus on objects at various distances. The way the lens of the eye works can be compared to the way a photographic camera maintains focus through movement of its lenses.

During a dog's lifespan, cells in the lens are constantly produced. With new cells forcing older cells inwards, as the dog ages, the fibers of the lens become more and more tightly compressed. Because there is little room for lens expansion, the lens is believed to become less clear as this process takes place. With the dog's lens growing denser and harder, dogs therefore develop the typical hazy appearance typically seen in an old dog with nuclear sclerosis.

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Generally, this cloudy appearance appears in dogs over the age of eight. Nuclear sclerosis most often affects both eyes. While this is a slowly developing condition, it can sometimes be noticed suddenly for the simple fact that the cloudiness can easily be missed under normal daily circumstances. It sometimes takes seeing the eyes under a certain light and looking at the eyes intently to take notice.

There are no particular dog breeds predisposed to this eye condition, but it appears that exposure to the sun can be a contributing factor for changes to a dog's lens.

While nuclear sclerosis isn't painful nor doesn't typically result in vision changes, on rare occasions, when the condition is very advanced, secondary changes may occur that lead to vision changes sufficient to warrant surgery.

Nuclear Sclerosis vs. Cataracts

dog-cataract picture

Though the two conditions may look the same, nuclear sclerosis isn’t the same as cataracts, a mineralized opacity within the dog's lens, causing a change in the ability of light to pass through the retina. As mentioned, while nuclear sclerosis doesn’t typically affect vision, cataracts causes diminished vision.

Cataracts and nuclear sclerosis are two of the most common eye problems seen in senior dogs. However, cataracts can also be seen sometimes in younger dogs. Though the two conditions may appear similar to a dog owner, a veterinarian using an ophthalmoscope can determine exactly which condition is affecting the dog.

Nuclear sclerosis is far more common than cataracts if we look at statistics. It is therefore more likely that an old dog with cloudy eyes is affected by nuclear sclerosis rather than cataracts.

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While some dogs with nuclear sclerosis do in fact develop cataracts, another common symptom of the aging process, the good news is that, despite the fact that cataracts does affect vision, this condition can be surgically corrected. Consider asking your veterinarian to fill you in on the procedure.

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"If the dog or cat is (at least) 8 or 10 years old and does not have significant visual deficits, the odds are better that it's nuclear sclerosis than cataracts," ~ Carmen Colitz, veterinarian and assistant professor of ophthalmology at The Ohio State University College of Veterinary Medicine.

Vet checks a dog's eye

Vet checks an old dog with hazy eyes.

At the Vet's Office 

If you have an old dog with hazy eyes, you want to mention this to your vet so the vet can evaluate your dog's eyes. Your vet will likely ask you several questions such as when you first noticed your dog's eyes becoming cloudy and if it seems to be affecting your dog's vision.

Your vet will then perform a physical exam and part of it will include looking at your dog's eyes. By visual inspection alone, sometimes the vet can deduce some pointers as to whether the dog has cataracts or nuclear sclerosis.

Cataracts appear like whitish chunks of crushed ice of various shapes, sizes and opacity. Also, while nuclear sclerosis affects both eyes, cataracts may be uni- or bilateral, explains veterinarian Dr. Joan Capuzzi.

Your vet will use an ophthalmoscope to look for signs of trouble. The eye exam may require the use of eye drops (topical tropicamide) that prevent the dog's pupils from constricting. The pupil dilation effect (medically known as mydriasis) is short-lasting and will typically only last about 15 minutes.

Retroillumination, using a slit-lamp is by far the best way to detect lenticular changes in old dogs. The room is darkened for this eye exam. If the vet is able to shine a light through the lens and see all the way back to the retina, then, the condition is diagnosed as nuclear sclerosis. If view of the retina is blocked instead, this is suggestive of cataracts. Consider that when the vet can’t see through your dog's lens, neither can your dog. If cataracts is present your dog's vision is therefore impaired to some extent and your vet may refer you to a veterinary ophthalmologist for more testing. If your dog has nuclear sclerosis, your vet will suggest you do nothing.

Dogs do not use their senses to ‘view’ the world in the same way humans do, nor do they rely upon vision as heavily as humans. Deteriorating vision or blindness would not nearly cripple the domesticated dog in the way it would a human. Though an old dog with hazy eyes affected by nuclear sclerosis won't likely suffer from vision loss, dogs with cataracts likely will; it is therefore important to remember (barring roads and traffic) your visually impaired fellow can still live out a completely happy life!

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  • DVM360: Cataracts: How to uncover the imposter lenticular sclerosis

Photo Credits:

  • Joel Mills - Own work, Nuclear sclerosis in a nine year old Collie mixed breed. This condition is often confused with a cataract. CC BY-SA 3.0
  • Flickr Creative Commons, Puppy Cataract, Chester has a cataract in his left eye, by nathanmac87, CCBY2.0

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