👁️ Cataracts in Diabetic Dogs – A 2025 Vet’s Guide to Vision Loss, Prevention, and Surgery

By Dr Duncan Houston, BVSc

🔍 What Is a Cataract?

A cataract is a cloudiness in the lens of the eye that prevents light from passing through normally. The lens, normally clear, becomes opaque—partially or completely—causing blurred vision or blindness. 🧬

🐶 Why Do Diabetic Dogs Get Cataracts?

In diabetes mellitus, high glucose levels in the eye fluid lead to sorbitol accumulation in the lens. Sorbitol pulls water into the lens, disrupting its clarity and forming cataracts. Fructose also contributes to this fluid imbalance. 💧

Even well-controlled diabetic dogs can develop cataracts.

⏳ How Fast Do Cataracts Form?

In diabetic dogs, cataracts often form rapidly—within weeks. The lens is living tissue, and its transparency is disrupted quickly when sugar levels are unbalanced. ⚠️

💊 Can Cataracts Be Prevented?

Kinostat®, an aldose reductase inhibitor, may prevent or delay cataract formation if started early. However, it is not yet commercially available. It cannot reverse cataracts once formed. ⏱️

🔎 Cataract Maturity Stages

The maturity of a cataract refers to how much of the tapetum (a reflective layer at the back of the eye) is blocked by the cataract:

• 🟢 Young: <10% obstruction
• 🟡 Early Immature: 10–50%
• 🟠 Late Immature: 51–99%
• 🔴 Mature: 100% tapetum obstruction (total blindness)

⚠️ Hypermature Cataracts

These begin to liquefy and may cause painful inflammation (uveitis). They do not restore vision and often worsen the prognosis for surgery. 🧨

🔥 What Is Uveitis?

Uveitis is inflammation of the eye's vascular layer and often follows a hypermature cataract. It causes:

• 🔴 Redness
• 😣 Pain
• ⚫ Pupil constriction

If present before surgery, the success rate drops from 95% to 50%. Timely intervention matters. 🎯

👁️ Can My Dog’s Vision Be Restored?

Maybe. Surgery can restore vision if the eye is otherwise healthy. A veterinary ophthalmologist will determine candidacy based on tests like the electroretinogram (ERG) to confirm retinal function. 🧪

⚠️ Don’t waste time on unproven “cataract-dissolving drops.” They don’t work and delay proper care.

🐕 Is It Cruel to Keep a Dog Blind?

No. Dogs adapt very well to blindness—especially if it’s painless. They rely heavily on scent and hearing and can live happy, active lives. Just avoid rearranging furniture and supervise them closely. 🛋️

🏥 Cataract Surgery: What to Expect

👨‍⚕️ Step 1: Regular Vet Exam

• 📊 Ensure diabetes is well-regulated
• 💉 Bloodwork and general anesthesia clearance

👁️ Step 2: Ophthalmologist Evaluation

• 🔎 ERG to confirm visual potential
• 🔬 Check for uveitis or other internal eye damage

🔧 Step 3: Surgery Options

• Phacoemulsification: Ultrasonic liquefaction and removal of the lens (preferred for diabetic dogs)
• Lens Extraction: Less commonly used due to more inflammation

💡 Post-Surgery

An artificial lens is typically implanted to restore vision. Some dogs do well without a lens but may have difficulty with sharp focus. 🩺

💊 Aftercare

• 🧴 Cortisone eye drops (weeks)
• 💊 Oral anti-inflammatories (weeks to months)
• 🔓 Dilating drops to keep the pupil open
• 🛡️ Elizabethan collar (cone) to prevent self-trauma

🚨 Possible Complications

• 🔥 Long-term uveitis
• ⚪ Capsule opacification (may be corrected with laser)
• 🌫️ Corneal clouding
• 🩸 Bleeding
• 🌡️ Glaucoma
• 🔌 Retinal detachment

🧐 One Eye or Both?

Many dogs only need one eye repaired to regain meaningful vision. Whether to do both depends on your dog’s lifestyle and your ophthalmologist’s advice. 👁️👁️

📲 Ask A Vet for Eye Care Support

Have a diabetic dog showing signs of vision loss? Reach out for advice on timing, surgery readiness, and monitoring. Visit AskAVet.com or download the Ask A Vet App to speak with a veterinary expert today. 🐶📱

✅ Summary: Key Points

• 👁️ Most diabetic dogs develop cataracts and can go blind
• ⚠️ Cataracts form rapidly and can lead to uveitis
• 🧪 Surgery may restore vision if the eye is otherwise healthy
• 💊 Kinostat may help prevent cataracts but isn’t yet available
• 🔧 Phacoemulsification is the preferred surgical technique
• 📈 Success depends on timing and overall eye health

💬 Final Words from Dr Duncan Houston

Cataracts in diabetic dogs are common—but treatable. Don’t let your dog suffer in silence. With proper care, many dogs regain their vision or adapt beautifully to life without it. The first step is always a conversation with your vet. 🐕❤️

We’re here to help—use the Ask A Vet App or visit AskAVet.com for real-time support and planning. 🐾📱