Cataract vs Glaucoma
What is the difference?
Both are among the most common causes of vision loss in India, yet they affect the eye in entirely different ways. One is curable with surgery. The other causes damage that cannot be undone. Understanding the difference matters to because the right response to each is not the same.
A cataract clouds the lens of your eye
The lens inside your eye is normally clear. When it clouds over to which happens gradually as the proteins within it break down and clump together to the result is a cataract. Light can no longer pass cleanly through, and your vision becomes blurred, washed out, or surrounded by glare.
The most important thing to understand about cataracts is that the damage is reversible. Surgery removes the clouded lens and replaces it with a clear artificial one. Vision returns, often dramatically. Most people who have cataract surgery say they wish they had done it sooner. See the cataract symptoms guide for the warning signs to watch for.
Blurred or misty vision
Especially when reading or looking at distant objects to as if looking through frosted glass.
Glare and halos around lights
Night driving becomes difficult. Headlights cause intense dazzle rather than simple brightness.
Fading or yellowing of colours
Colours look less vivid. Whites appear yellowish. The contrast between colours diminishes.
Glaucoma damages the optic nerve to silently
Glaucoma is a disease of the optic nerve, which connects the eye to the brain. When the pressure inside the eye rises beyond what the nerve can tolerate to or sometimes even when it stays in the normal range to the nerve fibres begin to die. The loss starts at the periphery of your visual field and slowly moves inward. By the time most people notice something is wrong, significant damage has already occurred.
Unlike a cataract, the nerve damage caused by glaucoma is permanent. This is what makes it the more dangerous of the two conditions. There is no surgery to restore vision that glaucoma has already taken to but there is treatment that can stop it from taking more. The glaucoma care page explains the treatment options available at Aadithya Eye Care.
Often no symptoms in early stages
Most glaucoma is entirely silent until the damage is advanced. This is why regular eye pressure checks matter.
Peripheral vision loss first
The edges of your visual field narrow. Central vision is preserved until late in the disease, which is why it is easy to miss.
Raised eye pressure (usually)
Intraocular pressure above 21 mmHg is a key risk factor, though normal-tension glaucoma also exists.
Cataract vs Glaucoma to key differences
A quick comparison of the two conditions on the dimensions that matter most for a patient trying to understand what they may be facing.
What Dr Vasantha Gowri
advises her patients
The most common mistake I see is patients who wait. With a cataract, waiting is understandable to it develops slowly and surgery can still restore vision later. With glaucoma, waiting is dangerous because the nerve damage that accumulates cannot be reversed. A patient who has had glaucoma for three years without knowing it has already lost nerve fibres that are gone permanently.
The good news is that both conditions are identifiable with a standard eye examination. Measuring eye pressure takes under a minute. Examining the optic disc gives immediate information about nerve health. Anyone over 40, or anyone with a family history of glaucoma, should have these checks done at least once a year. If you have diabetes, that frequency should increase to diabetic patients are at higher risk for both glaucoma and retinal disease.
Having both cataract and glaucoma at the same time is not unusual in older patients. We manage them together, adjusting the treatment plan based on how the eye responds. Neither condition requires a patient to travel far from Perambur for specialised care.
Aadithya Eye Care, Perambur
Cataract and glaucoma to
what patients ask
Questions we regularly hear from patients who come in having Googled their symptoms and arrived uncertain which condition applies to them.
Medical disclaimer: The content on this page is for general information only and does not constitute medical advice. Both cataract and glaucoma require a proper examination for accurate diagnosis. Content reviewed by Dr Vasantha Gowri, MBBS, DO (Ophthalmology), FICO (UK), FRCS (Glasgow), Aadithya Eye Care, Perambur, Chennai.
Learn more about your eye health
Cataract Surgery
Stitch-free phacoemulsification at Aadithya Eye Care to what to expect, lens options, and recovery.
Read moreGlaucoma Care
How glaucoma is monitored and treated at Aadithya Eye Care, from eye drops to surgical intervention.
Read moreCataract Symptoms
The early signs of cataracts and when to seek an eye examination in Chennai.
Read moreGlaucoma Symptoms
Why glaucoma is called the silent thief of sight and what the earliest detectable signs are.
Read moreIn-house Diagnostics
The equipment used at Aadithya Eye Care to examine eye pressure, optic nerve and lens health.
Read moreDr Vasantha Gowri
MBBS, DO (Ophthalmology), FICO (UK), FRCS (Glasgow), over 25 years in clinical practice at Aadithya Eye Care, Perambur.
Doctor profileMedical sources
- American Academy of Ophthalmology. Eye health information.
- National Eye Institute, National Institutes of Health. Eye conditions and diseases.
- All India Ophthalmological Society. aios.org.
Not sure whether it is cataract, glaucoma, or something else?
The only way to know is a proper examination. At Aadithya Eye Care in Perambur, we check both in a single visit to pressure, optic disc, lens, and retina. Book an appointment or walk in during clinic hours.