The IOL Master is a piece of specialty equipment that we use here in the office of Anderson & Shapiro Eye Care. It’s a simple test for you to do and provides your doctor with a wealth of information. Find out more as we dive into the next entry of our testing equipment series: the IOL Master.
What is an IOL Master?
IOL stands for intraocular lens, and we use these during cataract surgery to help improve your vision.
There are many different types of IOLs and each one comes with a wide range of different “powers”, similar to contact lenses or glasses.
The IOL Master is machine that gets several different measurements of your eye. These are necessary to determine which IOL power is best suited to your eye.
What does an IOL Master Measure?
There are several measurements that we take to determine what power of intra-ocular lens to implant.
Eye Curvature
The first is a measurement of the curvature of the front clear window of your eye. This is called keratometry, which breaks down from the Latin “Kerato” meaning cornea and “-ometry” meaning measurement of.
On top of seeing how curved it is, we can see how much focusing power it provides. Your cornea is 10-50x more powerful at focusing light than your glasses are! It works together with the natural lens in your eye and any glasses or contact lenses to focus light for you.
Eye Length
After measuring the cornea, the IOL Master measures how long your eyes are from front to back. This helps the doctor determine how light travels through your eye. Combined with how much power your cornea provides, we can start to calculate how much power your lens needs to be to perfectly focus light.
There are many different calculation formulas to use and some of them need even more specific information about your eyes, so we continue on!
Front Chamber
Between your cornea and the colored part of your eye (the iris) is a space we call the “anterior chamber.” This front area of the eye will show how far away from the cornea the natural lens of the eye sits.
Maybe you’ve noticed when you hold your glasses further away from your eye you can read a little better, or keeping them up closer to your eye helps you see far away a bit better. Or looking through a magnifying glass, that holding the glass closer or further away from the material changes it’s size.
The distance between two focusing lenses can change how much total power you experience, so we want to make sure when the cornea and lens are working together, the lens is in the right place to provide that total power.
Iris Width
The final eye structure that we measure with the IOL Master is your iris. We find out how wide your iris is, which we call White-to-White. This measurement is only important in certain types of implant lenses, which your doctor would only use if there were some complication or injury to your eye. We still obtain the measurement, so your doctor can make the best decision possible for you.
Why Does My Doctor Order an IOL Master?
The most common reason you would get an IOL Master measurement set of your eyes is in preparation of cataract surgery. Sometimes, we’ll do a procedure called a Refractive Lens Exchange or one called a Phakic IOL. Sometimes an injury causes an already implanted lens to move and requires a surgery to adjust it or replace it.
In all these cases, your surgeon would likely need these measurements of your eyes.
What is it Like?
Your skilled technician will guide you through the steps. Once your head is positioned properly in the headrest, your only job is to look at a fixation light. You may blink normally, though your technician may ask you to open wide for certain measurements.
You will see some bright lights and you may see vertical bars in your vision for a few minutes after.
The whole set of measurements usually takes 2-3 minutes per eye.
Summary
We hope this article has helped you understand what an IOL Master is, why your doctor might order it, and how easy it is to do. We’re always happy to answer more questions during your visit.