Dog Cataracts: Symptoms, Causes, Surgery and When to Act

If your dog's eyes have developed a bluish, grey or white haze — or if they're bumping into furniture, hesitating on stairs, or struggling in low light — cataracts may be developing. They're one of the leading causes of blindness in dogs but, in the right candidates, surgery is highly successful.

What Is a Cataract?

A cataract is an opacity of the lens — the internal optical element that focuses light on the retina. When the lens becomes cloudy, less light reaches the retina and vision progressively deteriorates. In advanced stages, vision is nearly completely lost.

Don't Confuse With Nuclear Sclerosis

Nuclear sclerosis is a normal age-related change where the lens gradually becomes denser (similar to hair going grey). It gives the eyes a bluish-grey appearance but rarely significantly affects vision. A veterinary ophthalmologist can reliably distinguish the two. Many owners are concerned about what turns out to be normal ageing rather than cataracts.

Causes

• Diabetes mellitus: The most common cause in adult dogs. Excess glucose in the lens creates sorbitol, which damages lens fibres. Diabetic cataracts progress extremely fast — sometimes within weeks.
• Hereditary: Common in Labrador, Golden Retriever, Poodle, Cocker Spaniel, Bichon Frisé. Can appear in young dogs.
• Trauma: A direct blow or eye penetration can opacify the lens.
• Chronic uveitis: Persistent intraocular inflammation damages the lens.
• Age: Senile cataracts are common but progress more slowly than diabetic ones.

Symptoms

• Visible lens opacity (grey, white, or bluish)
• Bumping into furniture or door frames, especially in new environments
• Hesitation on stairs or reluctance to jump
• Startling when touched unexpectedly
• Behaviour changes consistent with reduced vision

Diagnosis

A vet can identify cataracts with a slit lamp. For surgical planning, a veterinary ophthalmologist will perform:

• Electroretinography (ERG): confirms the retina is still functional — mandatory before surgery
• Ocular ultrasound: rules out retinal detachment
• Tonometry (eye pressure) and Schirmer tear test

Treatment

Surgery (Phacoemulsification)

The only treatment that restores vision. The cloudy lens is emulsified with ultrasound and removed, then an artificial intraocular lens (IOL) is implanted. The same technique used in humans.

• Success rate in experienced hands: 85–95%
• Best candidate: mature cataract, no active uveitis, healthy retina on ERG
• Poorer candidate: severe uveitis, secondary glaucoma, dysfunctional retina

Without Surgery

No eye drops or medications dissolve or reverse cataracts. Without surgery, the goal is managing complications: phacoclastic uveitis and secondary glaucoma can be painful even in an already-blind eye — requiring anti-inflammatory drops or, in severe cases, eye removal.

If Your Dog Goes Blind Without Surgery

Dogs adapt remarkably well to blindness as long as their environment stays consistent. Don't rearrange furniture, speak before touching them, and use scent markers to help them orient. Many blind dogs live happy, full lives.