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October 24, 2026
Glaucoma and cataracts are both common eye conditions of later life, but they affect different parts of the eye. A cataract is a cloudy area in the lens, the clear part that focuses light; it makes vision blurry, dim or glary, and surgery can fix it. Glaucoma is damage to the optic nerve, which carries vision from the eye to the brain; it usually starts in side vision with no early symptoms, and the vision it takes cannot be restored. Many people have both, and each can affect the other. This page compares them side by side.
For the condition as a whole, including the types, symptoms, who is at risk, how it is diagnosed, today’s treatments and the trials testing nerve protection, read our glaucoma guide.
| Question | Glaucoma vs cataracts |
|---|---|
| What it is | Glaucoma: a group of diseases that damage the optic nerve at the back of the eye. Cataracts: a cloudy area in the lens, the clear part of the eye behind the iris that focuses light. |
| Early symptoms | Glaucoma: usually none. Half of people with glaucoma don’t know they have it. Cataracts: often none while the cataract is mild. |
| Later symptoms | Glaucoma: loss of side vision, often starting on the side nearest the nose, then blind spots and, without treatment, blindness. Cataracts: cloudy or blurry vision, faded colors, poor night vision, glare from lamps and headlights, halos around lights, double vision and frequent changes of glasses. |
| Pain | Glaucoma: usually painless. Acute angle-closure glaucoma is the exception: sudden eye pain, redness and nausea are an emergency. Cataracts: painless. Rarely, a very advanced cataract leaks or swells and causes a painful glaucoma. |
| Main risk factors | Glaucoma: higher eye pressure, age over 60 (especially Hispanic/Latino), African American and over 40, and a family history of glaucoma. Cataracts: age, diabetes, smoking, heavy drinking, family history, eye injury or surgery, radiation to the upper body, a lot of sun exposure and steroid medicines. |
| Treatment | Glaucoma: eye drops, laser or surgery to lower eye pressure, usually for life. Cataracts: surgery to replace the cloudy lens with an artificial one, which can usually wait until the cataract bothers you. |
| Can lost vision come back? | Glaucoma: no. Treatment protects the vision you still have. Cataracts: yes. About 9 out of 10 people see better after surgery. |
| How common | Glaucoma: about 4.2 million US adults were living with glaucoma in 2022. Cataracts: more than half of Americans aged 80 or older have cataracts or have had cataract surgery. |
Cataracts change the quality of the whole picture. Vision gets hazier, colors look washed out, bright lights cause glare and halos, and reading in dim light gets harder. People usually notice these changes, even if slowly.
Glaucoma changes how much of the picture you see, and most people don’t notice. Early loss is in side vision, the brain fills in the gaps, and central vision often stays sharp until late. When people with glaucoma do notice something, they describe blurred or missing patches more than a dark tunnel. Our guide to what glaucoma looks like explains this in more detail.
The symptoms overlap enough that you can’t tell the two apart at home. Halos are a good example: they are common with cataracts, but halos with eye pain, redness, headache or nausea can mean acute angle-closure glaucoma and need emergency care. A dilated eye exam checks for both.
Yes, and it is common, because both become more likely with age. Having both makes testing and planning harder. A cataract can make visual field tests and nerve scans less clear, so your eye doctor has to judge how much of any change comes from the cataract and how much from glaucoma. Glaucoma can also limit how much vision improves after cataract surgery: MedlinePlus notes that when a person has another eye problem such as glaucoma, the outcome of cataract surgery may not be as good.
Yes, though this is uncommon. A cataract that becomes very swollen can push the iris forward and block the drainage angle, causing a sudden angle-closure attack (phacomorphic glaucoma). An over-ripe cataract can leak proteins that clog the drain (phacolytic glaucoma). Both can be painful, and removing the lens is the only definitive treatment. Delay can lead to permanent optic nerve damage.
More gradually, the lens thickens with age and can crowd the drainage angle in eyes that are already small or farsighted. That is one reason angle closure becomes more common in later life. Our guide to angle-closure glaucoma covers narrow angles in detail.
Often a little, and sometimes a lot. In people with high eye pressure in the Ocular Hypertension Treatment Study, pressure fell by an average of 16.5% after cataract surgery and stayed lower for at least three years; eyes with the highest pressure before surgery had the largest drops. Among people in the same study who were already using drops, about 23% of eyes no longer needed drops after cataract surgery and 41% needed fewer, although the pressure difference faded after about a year.
The benefit is larger in angle-closure glaucoma, because removing the lens opens the drainage angle. In the EAGLE trial of people aged 50 or older with angle closure and no cataract, removing the clear lens lowered pressure slightly more than laser iridotomy, improved quality of life and was more cost-effective.
Cataract surgery is also often combined with minimally invasive glaucoma surgery. In the pivotal iStent inject trial, 75.8% of eyes that had the stent with cataract surgery had at least a 20% fall in pressure without drops at two years, against 61.9% with cataract surgery alone. Our guide to glaucoma surgery and laser explains these options.
It can raise pressure for a while. The National Eye Institute lists unusual changes in eye pressure among the risks of cataract surgery, and a temporary rise in pressure is one of the more common early problems. The steroid drops used after surgery can also raise pressure in people who are sensitive to steroids, usually within three to six weeks of starting them, although it can happen sooner in very sensitive people. These rises are usually treated with glaucoma drops, but people who already have glaucoma, especially advanced glaucoma, need close checks after surgery.
Children are a special case. After cataract surgery in infancy, the risk of glaucoma in the Infant Aphakia Treatment Study rose to 22% by 10 years, so these children need lifelong pressure checks.
Yes. The National Eye Institute lists cataract as a risk of glaucoma surgery, and eye surgery is a known risk factor for cataracts. If you have both a significant cataract and glaucoma that needs surgery, your surgeon may suggest treating them together or in a planned order.
Netra Restoration Therapy (NRT) at Netra Eye Institute does not treat cataracts or glaucoma and cannot replace cataract surgery or pressure-lowering care. Once both conditions are treated and stable, some people still have trouble with scanning, reading or getting around because of glaucoma field loss. A functional assessment can target those tasks and coordinate with low-vision care.
Learn about Netra Restoration Therapy, Netra Eye Institute’s approach and low-vision rehabilitation.
A cataract is clouding of the eye’s lens, which blurs and dims vision and can be fixed with surgery. Glaucoma is damage to the optic nerve, usually linked to eye pressure, which takes side vision first and cannot be reversed. They affect different parts of the eye and are treated differently.
It depends. Cataract is the world’s leading cause of blindness, but that vision loss can usually be reversed with surgery. Glaucoma is the leading cause of irreversible blindness: the vision it takes is permanent and early glaucoma has no symptoms, so it has to be found early. Both need regular eye care.
Cataracts cause cloudy or blurry vision, faded colors, glare, halos, poor night vision and frequent changes of glasses. Glaucoma usually has no early symptoms; later it causes loss of side vision and blind spots. Sudden eye pain, redness, blurred vision and halos with nausea can be acute angle-closure glaucoma, which is an emergency.
No. It often lowers eye pressure a little, and in angle-closure glaucoma it can open the drainage angle, but it does not repair optic nerve damage. Monitoring and often other treatment continue. Our guide to whether glaucoma can be cured explains why.
Not directly; they are different diseases. But a very advanced cataract can swell or leak and cause a type of glaucoma, and the thickening lens can narrow the drainage angle over time.
Yes. Cataract surgery is commonly done in people with glaucoma and can sometimes be combined with glaucoma surgery. Your surgeon will plan for possible pressure rises afterward, and glaucoma damage may limit how much your vision improves.
Age is a major risk factor for both, but they have different causes. Cataracts also link to diabetes, smoking, sun exposure, steroids and eye injury. Glaucoma links to eye pressure, family history and ancestry.
Cataracts cloud the lens and are fixed with surgery. Glaucoma damages the optic nerve, takes vision permanently and has to be found early to protect what remains. Because you can’t reliably tell them apart from symptoms, and because many people have both, a regular dilated eye exam is the best protection against each.
Medical Disclaimer: This article provides general education and is not medical advice, diagnosis or treatment. Cataract and glaucoma care must be planned by a licensed eye-care professional. Sudden eye pain, redness, blurred vision or halos with headache, nausea or vomiting requires emergency care. NRT does not treat cataracts or glaucoma and must never delay or replace medical care.
