👁️ Causes of Blindness in Dogs and Cats – A 2025 Vet’s Guide to Eye Diseases and Vision Loss

By Dr Duncan Houston, BVSc

🔬 How the Eye Works

Vision begins with light passing through the cornea and pupil, then focused by the lens onto the retina, where light is converted into electrical impulses. These signals travel via the optic nerve to the brain, which interprets them into images. Problems at any point in this pathway can cause blindness. 🧠👁️

🐶🐱 Signs of Vision Loss in Pets

• 🚶‍♂️ Bumping into walls or furniture
• 🦴 Trouble finding food or toys
• 🐾 Hesitance in new environments
• 🔎 Disorientation or confusion

If you suspect vision loss, your veterinarian can determine the underlying cause and explore options. 📋

🧪 Common Causes of Blindness

1. 🔥 Uveitis

Uveitis is inflammation of the uvea, which includes the iris, ciliary body, and choroid. Causes include infections (e.g., FIP, ehrlichiosis), trauma, tumors, toxins, and immune-mediated diseases. Uveitis is painful and can lead to blindness if untreated. ⚠️

2. 👁️ Cataracts

A cataract is cloudiness in the lens that blocks light from reaching the retina. They’re usually painless but cause progressive vision loss. Common causes:

• 🧬 Genetics (especially in dogs)
• 💉 Diabetes mellitus (particularly in dogs)
• ⚡ Trauma or electric shock
• 📉 Nutritional deficiencies
• 🧓 Age-related changes

In cats, cataracts are most often secondary to uveitis. 👨‍⚕️

3. 💥 Glaucoma

Glaucoma results from increased pressure in the eye due to poor fluid drainage. This pressure can quickly damage the retina and optic nerve, leading to blindness. Causes include genetics (primary) and secondary triggers like uveitis or lens luxation. Symptoms include:

• 🌑 Enlarged eye
• 😞 Eye pain, squinting
• 📉 Sudden vision loss

4. 🧠 Retinal Detachment

The retina is a layered structure that converts light into brain signals. Detachment means light signals can’t be transmitted. Causes include:

• 🧬 Genetics
• ⚡ Trauma
• 🦠 Infections or immune diseases
• 🔁 Uveitis or eye surgery
• 📈 High blood pressure

5. 📉 Progressive Retinal Atrophy (PRA)

PRA is an inherited retinal degeneration that leads to blindness over time, typically starting with night vision loss. It’s more common in dogs than cats and may be accompanied by cataracts. 📉

6. 🚨 SARDS (Sudden Acquired Retinal Degeneration Syndrome)

SARDS causes sudden, irreversible blindness in dogs over days to months. The cause is unknown and the retina appears normal initially, which can make diagnosis tricky. ⚠️

7. ⚡ Optic Neuritis

Inflammation of the optic nerve disrupts visual signals from eye to brain. Causes include:

• 🐶 Distemper (dogs)
• 🐱 Cryptococcosis (cats)
• 🦠 Infections, immune conditions, trauma, tumors

8. 🔄 Lens Luxation

The lens is held by fine ligaments; if they break, the lens can shift:

• ⏩ Forward = blocks fluid drainage → glaucoma
• ⏪ Backward = risk for retinal detachment

Terrier breeds are especially prone to this inherited issue. 🐕

9. 🩹 Corneal Diseases

Conditions like keratoconjunctivitis sicca, pigmentary keratitis, and pannus can scar the cornea and lead to blindness if untreated. Regular vet exams and treatment with eye medications are key. 👁️

🧪 Differentiating Cataracts from Other Eye Issues

Cloudy eyes are not always cataracts. Nuclear sclerosis is a harmless age-related change that can look similar. Your vet can examine your pet to distinguish between them. 🔬

👨‍⚕️ What to Do If You Suspect Vision Loss

• 📅 Schedule a veterinary eye exam
• 📸 Consider specialist referral if needed
• 🧪 Tests may include ERG, ultrasound, bloodwork, or eye pressure checks

💡 Early detection makes a big difference—some causes are treatable or manageable if caught in time.

📲 Ask A Vet for Vision Concerns

Noticing signs of blindness in your dog or cat? Our team can help assess urgency, guide your next steps, or refer you to an eye specialist. Use the Ask A Vet App or visit AskAVet.com for real-time support. 🐶🐱📱

✅ Summary: Top Causes of Blindness

• 🔥 Uveitis (inflammatory eye disease)
• 👁️ Cataracts (especially in diabetic dogs)
• 💥 Glaucoma (high eye pressure)
• 🔄 Retinal detachment or degeneration (PRA, SARDS)
• ⚡ Optic neuritis or lens luxation
• 🩹 Corneal scarring diseases

💬 Final Words from Dr Duncan Houston

Blindness in pets can be sudden or slow, painful or painless—but it’s always stressful for pet parents. Fortunately, with early diagnosis and good support, many causes of vision loss can be treated or managed. 🐾💙

Still unsure what’s affecting your pet’s eyes? Chat directly with a vet today through the Ask A Vet App or at AskAVet.com. 👁️🐶🐱