Eye measurement before cataract surgery (biometry)
eye biometry · IOL calculation · lens power calculation · eye length measurement
A machine measures the length of your eye and the curve of your cornea. These numbers are used to choose the artificial lens for surgery.
Before cataract surgery, and sometimes before other lens surgery.
⏱ Duration: usually 10 to 20 minutes; results right away
Be sure to tell your doctor
How to prepare
- Contact lenses. Contact lenses are usually stopped a few days before. The clinic will tell you how long.
- Makeup. Come without eye makeup.
- Getting home. If your pupils will be widened, it is better not to drive afterward.
What to bring
- Your ID
- Your glasses
- Notes from past eye surgery, if any
- Someone to go with you, if you will have drops
How it goes
- You sit at the machine with your chin on the stand
- You look at a light
- The machine measures each eye with light, without touching it
- Sometimes ultrasound is used after numbing drops
- The doctor calculates the lens power
What you'll feel
- It does not hurt
- The light is bright, and you need to look without blinking for a few seconds
Afterwards
- If you had drops, do not rub your eyes
- The result is used to choose your lens
- The surgery date is usually set at your visit
Common questions
Why measure if the surgery is standard?
Every eye is different. An accurate calculation decides how you will see after surgery.
Can I choose a lens so I can read without glasses?
Talk to your surgeon. There are different options, and the doctor will suggest the right one.