Glaucoma vs Cataract
One is reversible and the other is not. A cataract clouds the lens and surgery replaces it; glaucoma damages the optic nerve, and what it takes does not come back.
- Six differences, side by side
- Both are common after 60, and both can be present
- Six clinics in five locations islandwide
Camden (Orchard)Joo ChiatClementiBedokToa Payoh
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Over 99% success rate and generally safe
Minimal downtime — under 1% have major complications based on studies. Talk to our friendly cataract surgeons to understand more.
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Regional Key Opinion Leader in glaucoma
A role Dr Jayant V Iyer is engaged in by Santen and Alcon, who make glaucoma medicines and devices.
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Conservative treatment first
Drops or laser where they will do the job, and surgery only as a last resort.
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The difference between glaucoma and a cataract
They are often confused, they are both common after 60, and plenty of people have both at once. They are not versions of the same thing.
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Glaucoma — the nerve thins, the lens is unaffected
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Cataract — the lens clouds, the nerve is unaffected
| What is compared | Glaucoma | Cataract |
|---|---|---|
| What goes wrong | The optic nerve is damaged, usually by pressure inside the eye. | The eye’s natural lens clouds, mostly with age. |
| What you notice | Usually nothing, until a lot of side vision has gone. | Misty or dulled vision, glare at night, colours washing out. |
| Which vision goes | Side vision first, from the edges inward. | Central and general clarity — the whole picture dims. |
| Can it be reversed | No. Lost nerve does not recover. | Yes. Surgery replaces the clouded lens. |
| What treatment does | Lowers the pressure to protect the vision that remains. Usually lifelong. | Removes the cause. A cataract does not grow back afterwards. |
| How it is found | Pressure, optic nerve and visual field checked together. | Seen directly on examination of the lens. |
Symptoms of cataracts and glaucoma
One of them is noticeable and the other, in its common form, is not. That is the practical difference between them.
What a cataract makes you notice
- Misty or dulled vision that a new prescription no longer sharpens.
- Glare by day, and haloes around lights at night. Oncoming headlights spread.
- Colours washing out, and whites looking yellowed.
- Needing more light to read than you used to.
- It is gradual and painless, and the two eyes are often at different stages.
What glaucoma makes you notice
- Usually nothing in the common open-angle form. Side vision goes first, from the edges inward, and the other eye covers the gap.
- Later, catching door frames on one side, misjudging steps and kerbs at night, or needing more light to read.
- The centre of your vision, and your reading, can stay clear while that happens.
- The less common angle-closure form is the opposite: sudden pain, redness, haloes and nausea. That one is an emergency and needs a hospital the same day.
Two complaints sit on both lists — haloes around lights, and needing more light to read — which is part of why the two are confused. Neither list settles which you have.
The fuller picture is on the symptoms of a cataract and under the signs of glaucoma.
Can you have both at once?
Yes, and after 60 it is common. Both become more likely with age, and having one does not protect you from the other.
They are treated separately, because they are different problems. A cataract is removed once it is getting in your way, and it does not come back. Glaucoma is managed by lowering the pressure inside the eye, usually for life. Removing a cataract does not treat glaucoma, and treating glaucoma does not clear a cataract.
Which is dealt with first depends on which one is affecting your sight, and that is a decision to take with the eye specialist looking after you.
If a clouded lens is what is blurring your vision, how a cataract is treated sets out what that operation involves. If it is the pressure you have been told about, glaucoma covers the range, the tests and the treatment. If you have not been told which you have, a comprehensive eye check-up looks for both.
Which is worse, cataracts or glaucoma?
Glaucoma is the more serious of the two, because the sight it takes does not come back. A cataract causes more day-to-day difficulty sooner — it dims the whole picture and you notice it — but surgery reverses it. Glaucoma usually causes nothing you would notice until a good deal of side vision has already gone.
That is why the two are managed differently. A cataract can be watched until it bothers you, because the sight is recoverable. Glaucoma is worth finding early, because treatment protects the vision that remains rather than restoring what has gone.
Choosing who treats you? See what to look for in a glaucoma specialist or how to find the right cataract surgeon.
Not sure if you have glaucoma or a cataract? Talk to our friendly staff for a same-day appointment (subject to availability).
Watch Dr Jayant V Iyer and Dr Jason Lee explain what glaucoma is
Watch Dr Jayant V Iyer explain what a cataract is
Not sure which one you have?
Send us a message with what you have been told and a time that suits, and we will arrange an examination.
