SINGAPORE – Many dog owners use the word “cataracts” when they see cloudiness in their dogs’ eyes, drawing from their knowledge of how cataracts affect ageing people.

However, what they are seeing is often nuclear sclerosis, not cataracts. Every dog will experience nuclear sclerosis, which is a normal change as a result of ageing that makes the lens appear slightly cloudy, like looking through lightly frosted glass.

Unlike cataracts, nuclear sclerosis does not cause pain or vision loss. True cataracts are opacities in the lens that block vision. A veterinary ophthalmologist’s specialised equipment and knowledge can help to differentiate the two conditions.

While nuclear sclerosis occurs in cats, it does not look so white in their eyes compared with the condition in dogs.

In Singapore, lanosterol eye drops are being marketed for dissolving cataracts in dogs, but these products may rob dogs of their sight by delaying proper treatment.

Dog owners may opt for these eye drops to avoid general anaesthesia and surgery, as well as for ease of their use, accessibility and seemingly few side effects.

Companies selling these eye drops mainly cite one published 2015 journal article that has since been debunked. However, these eye drops, sold at some veterinary clinics in Singapore , continue to sell like hot cakes despite poor evidence supporting their use.

In the 2015 study , which was published in academic journal Nature, photographs showing the reduction in cataract severity in dogs were subjectively graded. The pictures appeared to show nuclear sclerosis (normal lens ageing change) rather than cataracts. 

A dog experiencing nuclear sclerosis, which is a normal ageing change that makes the lens appear slightly cloudy, like looking through lightly frosted glass.

PHOTO: GLADYS BOO

Lanosterol has poor penetrative ability and is unlikely to reach the lens after application on the surface of the eye. 

A 2019 study showed that compounds such as lanosterol fail to restore lens clarity. 

The “success” stories owners report may be due to misunderstanding. Dog lenses look different under various lighting conditions, making it easy to imagine improvement.

If the dog has only nuclear sclerosis, owners may think the drops work because their dog has not gone blind after years of use. When dogs develop true cataracts later, owners may assume the drops initially helped prolong their dog’s vision.

One concerning scenario is when an untreated cataract causes the lens to dislocate and drop into the back of the eye, a condition known as lens luxation.

The cataract disappears from view, leading owners to believe the drops dissolved it. But this is not due to the drops – it is usually followed by serious complications like glaucoma and retinal detachments.

Glaucoma is a condition when the eye pressure increases, causing irreversible blindness and pain; often necessitating eye removal for pain relief.

Delayed treatment may lead to eyeball removal

In dogs that actually have cataracts, using these eye drops delay owners from seeking treatment.

True cataracts can cause glaucoma, inflammation and retinal detachments. These secondary complications usually lead to pain in the dog’s eye.

As a last resort, an ophthalmologist may have to recommend removal of the eyeballs for pain relief.

The eye cannot be saved after the narrow window of opportunity to perform cataract surgery has passed.

Symptoms to watch out for include cloudiness in the eye, redness, squinting, bumping into things or seeming unconfident on walks or finding toys.

Seek advice from your vet who may be able to perform a general eye examination. Your vet may refer you to a board-certified veterinary ophthalmologist for a definitive diagnosis. 

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Cataracts in dogs are commonly inherited rather than caused by old age. In addition, they can develop overnight and become a surgical emergency. This condition occurs very frequently in dogs in Singapore because of the poor inbreeding practices here.

Do not waste your money on unproven therapies. It will prove to be more expensive after totalling the cost of placebos and the vet visits to deal with complications.

Sight is a precious gift to any living being. Without it, the pleasures of life can be diminished.

Dr Gladys Boo is the only Diplomate of the American College of Veterinary Ophthalmologist in Singapore. She is a veterinarian at The Eye Specialist for Animals.

Vet Talk is a fortnightly column where veterinarians offer advice on pet issues.

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