Cataracts in Cats With Diabetes: What to Expect

Name: Cataracts in Cats With Diabetes: What to Expect
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-02

Cataracts in cats with diabetes happen when high blood sugar damages the lens, causing cloudy eyes and vision loss. In cats, this often develops quickly, sometimes within weeks to months of a diabetes diagnosis, and it can affect one or both eyes. The good news is that many diabetic cats adapt well to vision changes, and some can have their sight restored with surgery.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Diabetic cataracts form when sugar builds up in the lens and pulls in fluid, which breaks down lens proteins and makes the lens cloudy [1].
Most cataracts in cats are linked to other eye disease or inflammation, but diabetes is a known cause of cataract formation [2].
Cloudy eyes in a diabetic cat can appear suddenly, and both eyes are often affected around the same time.
Cataract surgery (phacoemulsification) can restore vision in some cats, but it requires a full health workup first [3].
Even without surgery, regular veterinary monitoring matters because cataracts can lead to uveitis, glaucoma, and a shrunken, blind eye [2].

What Are Cataracts in Cats With Diabetes?

A cataract is a clouding of the lens, the small clear structure behind the iris that focuses light onto the retina [4]. When the lens turns cloudy or opaque, light cannot pass through normally, so vision drops. The change can be tiny and barely noticeable, or it can cover the whole lens and cause blindness in that eye [4].

Cataracts can affect one eye (unilateral) or both eyes (bilateral) [4]. In diabetic cats, both eyes are commonly involved.

It helps to know what a cataract is not. A cloudy eye in an older cat is often lenticular sclerosis, a normal aging change that looks hazy but does not block vision the way a cataract does. Your veterinarian can tell the difference during an eye exam.

Diabetic Cat Cataracts: Why Diabetes Causes Cloudy Eyes

The lens normally gets its nutrients from the fluid around it, not from blood vessels. When blood sugar stays high, sugar enters the lens and converts into another compound that draws water in. That extra fluid disrupts the tightly packed lens proteins, and the lens starts to cloud [1].

This process is driven largely by oxidative stress, the same kind of cell damage that plays a role in many diabetic complications [1]. Research into diabetic cataracts in people and animals continues, and scientists are looking at ways to slow the process with medication, though no approved preventive drug exists for cats today [5].

One important difference between species: in dogs, diabetic cataracts are extremely common and often develop fast. In cats, most cataracts are not "spontaneous" and are more often tied to inflammation inside the eye (anterior uveitis) or to inherited disease in young cats [2]. Diabetes is still a recognized cause, but a diabetic cat with a cloudy eye needs a full eye exam to rule out uveitis and other problems [2].

Signs Owners Notice

Early cataracts can be easy to miss. Watch for:

A gray, white, or milky haze in the pupil area
Bumping into furniture or misjudging jumps
Hesitating on stairs or in dim light
Startling easily when approached
Less interest in toys or play
Squinting, redness, or a change in eye color (this points to inflammation, not just a cataract)

Because diabetic cats also drink and urinate more, you may notice those signs first. If you are tracking thirst and output at home, this guide on how to tell if your cat's increased thirst is a sign of kidney disease or diabetes can help you sort out what you are seeing.

How Fast Do Cataracts Develop in Diabetic Cats?

This is the question owners ask most. In dogs, diabetic cataracts can mature in weeks. In cats, the timeline is more variable and less predictable. Some diabetic cats develop lens clouding within months of diagnosis, while others live for years with diabetes and never form a significant cataract.

Veterinary research has not pinned down a reliable average time frame for cats, so treat any sudden change in your cat's eyes as a reason to call your vet. Rapid clouding, especially with squinting or redness, needs prompt attention.

How Veterinarians Diagnose Cataracts

Diagnosis starts with a complete eye exam. Your veterinarian will use a light and often a slit lamp or ophthalmoscope to see how much of the lens is cloudy and whether the cloudiness is in the lens or somewhere else in the eye.

Other tests may include:

Tonometry to check eye pressure, since glaucoma can accompany lens disease [2]
Ocular ultrasound to look at the lens and retina when the cataract is too dense to see through. In one reported case, ultrasound revealed a distorted lens capsule that changed the surgical plan [6]
Electroretinography (ERG) to confirm the retina still works before considering surgery [3][6]
Blood work and infectious disease testing to rule out uveitis causes such as feline leukemia virus, feline immunodeficiency virus, and toxoplasmosis [3]

Your vet will also review how well your cat's diabetes is controlled. Good glycemic control supports overall health and may reduce the risk of complications during any procedure. If you are new to monitoring, this article on monitoring blood glucose curves in diabetic dogs and cats explains the basics.

Treatment Options for Diabetic Cat Cataracts

Surgery

The main treatment for cataracts is surgery to remove the clouded lens, a procedure called phacoemulsification [2]. In one published case, a diabetic cat with cataracts in both eyes had successful surgery that restored vision, though an artificial lens was placed in only one eye because of pre-existing changes [3]. Another case described successful surgical treatment of a mature cataract in a cat with no detectable uveitis [6].

Surgery is not right for every cat. Candidates need a working retina, controlled diabetes, and no active eye inflammation. Complications are possible, and the cost is significant. Your veterinarian or a veterinary ophthalmologist will decide whether your cat is a candidate.

Medical Management

If surgery is not an option, the focus shifts to comfort and monitoring. Cataracts can trigger anterior uveitis, glaucoma, and a blind, shrunken eye, so continued veterinary checkups are important [2]. Your vet may prescribe eye drops to control inflammation or pressure. Never use human eye drops in your cat without veterinary direction.

Managing Diabetes Itself

Tight diabetes control is the foundation of care. The 2026 AAHA Diabetes Management Guidelines for Cats cover insulin options, diet, activity, and home glucose monitoring, and they note that remission is possible for some cats [7]. Better glucose control supports eye health and overall wellbeing. If your cat is on glargine insulin, this guide on insulin glargine for cats: feline diabetes dose and glucose curve walks through what to expect. Your veterinarian calculates the dose from your cat's weight and health, so never adjust insulin on your own.

A Quick Comparison

Approach	What It Does	Best For	Main Limits
Phacoemulsification	Removes the clouded lens and can restore vision [2]	Cats with a healthy retina and controlled diabetes [3][6]	Cost, anesthesia risk, possible complications
Medical management	Controls inflammation and eye pressure [2]	Cats who are not surgical candidates	Does not restore vision
Diabetes control	Supports overall health and may aid remission [7]	Every diabetic cat	Does not reverse an existing cataract

Recovery, Outlook, and Long-Term Management

After cataract surgery, most cats need a period of restricted activity, frequent rechecks, and eye drops. Vision often returns quickly when the retina is healthy, as seen in the reported case where surgery restored sight in both eyes [3].

Without surgery, many cats adjust surprisingly well. Cats rely heavily on hearing, smell, and memory. Keep furniture in place, talk to your cat before touching, and use night lights. Block stairs and pool areas if vision is poor.

Long-term, plan on:

Regular eye exams to catch uveitis or glaucoma early [2]
Ongoing diabetes monitoring, including glucose checks and vet visits [7]
Watching for other diabetes complications. One report described congestive heart failure in two diabetic cats that improved with better glycemic control, which shows how diabetes can affect organs beyond the eyes [8]
Keeping your cat at a healthy weight, since obesity raises diabetes risk up to four times [9]

If your cat shows signs of stomach upset or stops eating, that can signal pancreatitis, which is common in diabetic cats. Learn the signs in this guide on pancreatitis in cats symptoms. And if you are looking for treats that will not spike blood sugar, see safe treats for diabetic cats.

Prevention

You cannot guarantee your cat will never develop a cataract, but you can lower the odds and catch problems early.

Control blood sugar. Good diabetes management is the single most important step [7].
Keep your cat lean. Obese cats are up to four times more likely to develop diabetes in the first place [9].
Encourage activity. Daily play supports weight and glucose control [9].
Schedule regular eye checks. Early detection of uveitis or lens changes allows faster treatment [2].
Know the limits. No approved medication prevents diabetic cataracts in cats today, though research into drug options is ongoing [5].

Limitations and When to Contact a Veterinarian

Call your veterinarian promptly if you notice:

Same day: sudden cloudiness in one or both eyes, squinting, pawing at the eye, or redness
Emergency now: a bulging eye, severe pain, sudden blindness, or a cat that will not eat or is vomiting repeatedly
Routine visit: gradual haze in the eyes, mild vision changes, or any new behavior that suggests your cat cannot see well

Every cat is different, and only your veterinarian can examine your cat, confirm the diagnosis, and set a treatment plan. Do not wait to see if a cloudy eye clears up on its own.

Frequently Asked Questions

Can a diabetic cat's cataracts be reversed without surgery?

No, a cataract will not clear on its own without surgery. Medical treatment can control inflammation and pressure but cannot restore the lens [2]. Some cats adapt well to vision loss with help from you at home.

Will my diabetic cat go blind?

Not necessarily. Some diabetic cats never develop a significant cataract, and others keep useful vision for a long time. If a cataract does mature, it can cause blindness in that eye, and surgery may restore sight in suitable candidates [4][3].

Is cataract surgery safe for diabetic cats?

It can be, but it requires careful screening. Candidates need a working retina, controlled diabetes, and no active uveitis [3][6]. Your veterinary ophthalmologist will weigh the risks and benefits for your cat.

Do cataracts hurt my cat?

The cataract itself is not painful, but the eye problems it can trigger are. Cataracts can lead to uveitis and glaucoma, which do cause discomfort [2]. That is why ongoing monitoring matters even if you choose not to pursue surgery.

How often should a diabetic cat have eye exams?

Ask your veterinarian, since the schedule depends on your cat's control and eye health. As a general rule, eye checks at regular diabetes rechecks help catch problems early, and any new eye sign warrants a sooner visit [2][7].

References

Enzymatic and biochemical properties of lens in age-related cataract versus diabetic cataract: A narrative review. Indian journal of ophthalmology, 2023.
Disorders of the Lens in Cats - Cat Owners. Merck Veterinary Manual.
Rare occurrence of an intumescent cataract in a diabetic domestic longhair cat. JFMS open reports, 2026.
Feline Cataracts. Cornell University College of Veterinary Medicine.
Ameliorating effect of the aldose reductase inhibitor 1-Acetyl-5-phenyl-1 H-pyrrol-3-ylacetate on galactose-induced cataract. Scientific reports, 2025.
Ultrasonographic Appearance of a Posterior Lenticonus in a Cat. Veterinary ophthalmology, 2026.
2026 AAHA Diabetes Management Guidelines for Cats. Journal of the American Animal Hospital Association, 2026.
Reversible congestive heart failure associated with diabetes mellitus in two cats. JFMS open reports, 2026.
Feline Diabetes. Cornell University College of Veterinary Medicine.