Cataracts and retinopathy are diabetes complications in dogs. Both complications can cause blindness. Take your dog to an ophthalmologist if it shows signs of blindness, such as bumping into objects, confusion, or depression.
Dogs can develop vision problems, including blindness. This can occur suddenly or gradually.
The causes of blindness in dogs are many, and one of them is diabetes. Cataracts and retinal disorders (retinopathy) are complications of diabetes.
These can lead to sudden blindness due to cataracts, or gradual blindness due to retinopathies.
In this article, you will find out if diabetic dogs can go blind and what the symptoms of blindness in diabetic dogs are. You will also learn if blindness in diabetic dogs can be reversed, and much more.
Can Diabetes Make My Dog Blind?
Complications of diabetes can lead to gradual or sudden blindness in dogs. Diabetic cataracts lead to sudden blindness while retinal disorders lead to gradual blindness. Dogs develop these complications if their blood sugar levels are elevated for a long time.
Diabetes complications usually occur when a diabetic dog is left undiagnosed and untreated for a long time.
Elevated blood sugar levels (hyperglycemia) for a long time can lead to two complications related to blindness:
- Cataract (common).
- Disorders of the retina and optic nerve (rare in dogs).
Related: 17 Symptoms of Diabetes in Dogs
Sudden vs. Gradual Blindness
The main difference between the sudden and gradual onset of blindness is the cause. Sudden blindness occurs when diabetic dogs develop cataracts. Gradual blindness occurs when diabetic dogs develop retinopathy.
Sudden blindness in a diabetic dog most often occurs due to cataracts, which is a very common complication of diabetes. It is estimated that 75% of dogs with diabetes become blind from cataracts in one year after developing it. 
Gradually blindness can go unnoticed by the owner for a long time. Dogs know their home well, allowing them to avoid obstacles. Even if they are partially blind.
Owners begin to realize something is wrong with their pets when they are in a foreign place. This is when their dog will bump into objects or get easily startled.
Early Signs of Blindness in Diabetic Dogs
The early symptoms of blindness in diabetic dogs are subtle and go unnoticed by many owners.
Here are common early signs of blindness in diabetic dogs:
- Lower activity levels
- Sudden aggression
- Unexplained lethargy
Consult your veterinarian if you think your dog has vision problems
Symptoms of Blindness in Diabetic Dogs
Blindness can be extremely stressful for a dog that wakes up without its sight overnight. Your dog needs to learn how to navigate, relying on its other senses.
Here are the most common clinical signs of blindness in diabetic dogs:
- Bumping into walls or objects.
- Reluctancy to move.
- Startles easily when petted or approached.
- Strong reactions to noise.
- Avoidance of stairs.
- Pawing at the face.
- Sleeping longer than usual.
- Sleeping at other times.
- Eyes look cloudy (cataracts).
- Pupils don’t dilate or constrict.
Cataracts in Diabetic Dogs
Cataracts are a complication of diabetes in dogs. It occurs when blood glucose levels are high for a long time. Cataracts can lead to blindness within 48 hours in some cases.
Cataracts and vision loss occur due to long-term elevated blood sugar and high blood pressure. These directly affect the:
- Vitreous body
- Crystalline lens
- Optic nerve
Cataracts can occur in diabetic dogs 5-6 months to 12 months after the diagnosis of the disease. This complication develops extremely quickly and can lead to blindness in less than 48 hours.
In cataracts, the crystalline (the lens of the eye) becomes cloudy and appears as a hazy, opaque white growth.
This opacification occurs gradually, making it difficult to notice for most dog owners.
Why Do Diabetic Dogs Get Cataracts?
Diabetic dogs develop cataracts because the lens absorbs glucose from the surrounding fluids.
The lens of the eye is a vital component. It is a piece of living tissue as clear as glass. The lens is encapsulated and has no direct blood supply. It feeds with the ocular fluids surrounding it.
The eye lens absorbs glucose from the ocular fluids. Excess sorbitol (sugar alcohol obtained by reducing glucose) occurs when there are excess amounts of sugar in these fluids. Sorbitol draws water into the lens and disrupts its clarity, resulting in cataracts.
The presence of cataracts does not necessarily mean your dog’s diabetes is poorly treated. Properly treated dogs can get cataracts too.
Cataracts have three stages:
1. Incipient Cataracts
In incipient cataracts, you can observe a slight opacification of your dog’s eye. Your pet’s general vision is not too affected in this phase.
The pupil will gradually change from black to blue or white. If your dog’s eye becomes cloudier and your dog’s behavior changes, the cataract may have passed to the next stage and become mature.
2. Mature Cataracts
In mature cataracts, the eye becomes completely opaque, and your dog loses its sight. The pupil will gradually change from black to blue or even white.
It is important to seek veterinary advice to stop the cataract from progressing.
3. Hyper-Mature Cataracts
Mature cataracts can turn hyper-mature if left untreated. Hyper-mature cataracts are characterized by the wrinkling of the lens. The only option to save your dog’s vision is surgery.
Cataracts do not endanger your dog’s life. But they modify it, making normal tasks difficult.
Diabetic retinopathy is a less common complication of chronic diabetes in dogs. It occurs when high blood glucose levels affect the retinal blood vessels.
Diabetic retinopathy develops when glucose levels are elevated for a long time. The exact cause is unknown, but it appears that high glucose levels affect the retinal vessels.
This complication of diabetes can take several years to develop. Most dogs develop it in 1.4 years. 
Diabetic retinopathy can also occur if diabetes is properly diagnosed and treated.
Can Diabetic Blindness in Dogs Be Reversed?
You can reverse blindness in diabetic dogs if you act when the early signs appear. The incipient and mature stages of cataracts are resolved with appropriate anti-diabetic treatment. Severe cases are reversed with lens replacement surgery.
The reversal of blindness in diabetic dogs depends on the stage of cataracts:
- Cases of mild cataracts in dogs with diabetes are remedied with appropriate treatment (insulin).
- Cases of hyper-mature cataracts are remedied by surgical removal of the affected lens.
The surgery is performed in both eyes. The good news is that once your dog has synthetic lenses, cataracts won’t reoccur.
Blindness can be permanent if surgery is not performed quickly to fix the cataract.
If diabetic retinopathy is not treated in time, the damage can be so severe that blindness is permanent.
How Do I Keep My Diabetic Dog From Going Blind?
Blindness is best prevented with regular visits to the vet. Your vet will watch for the first signs of vision impairment. This ensures early diagnosis and treatment. Regular checkups reduce the chances of your dog developing blindness. Treating eye problems in diabetic dogs is always more difficult than preventing them.
Can My Dog’s Vision Be Restored?
Your diabetic dog’s vision can be restored if diagnosed early. If the blindness is caused by cataracts, lens replacement surgery can reverse the problem. Blindness can remain permanent if your dog’s eye is severely damaged or inflamed. Only the vet can give you an answer if your dog’s blindness can be reversed or not after a complete examination.
Why Is My Diabetic Dog Going Blind?
When sugar builds up in the lens of the eye, it can lead to diabetic cataracts. This condition causes the eye to become opaque and brittle, and your dog can lose its sight within 48 hours of developing cataracts. Diabetic cataracts are not the same as cataracts that occur with age.
Can Insulin Make Dogs Blind?
Insulin cannot make a dog go blind. Diabetic dogs do not produce enough insulin. The role of insulin is to lower blood sugar. When blood glucose levels are elevated for a long time, diabetes can lead to cataracts and/or retinopathy. Both can lead to blindness if left untreated.