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What Is Intraoperative Aberrometry?

Yes, that is a mouthful, but the concept isn’t quite as hard as the name.

An Intraoperative Aberrometer is an instrument we can use in the operating room to help us determine the correct power of the implant we put in your eye during cataract surgery.

Cataract surgery is the removal of the cloudy natural lens of your eye and the insertion of a new artificial lens inside your eye called an intraocular lens (IOL).

The cloudy cataract that we are removing has focusing power (think of a lens in a camera) and when that lens is removed, we need to insert an artificial lens in its place to replace that focusing power. The amount of focusing power the new IOL needs has to match the shape and curvature of your eye.

To determine what power of lens we select to put in your eye, we need to measure the shape and curvature of your eye prior to surgery.  Once we get those measurements, we can plug those numbers into several different formulas to try and get the most accurate prediction of what power lens you need.

Overall, those measurements and formulas are very good at accurately predicting what power lens you should have. There are, however, several eye types where those measurements and formulas are less accurate at predicting the proper power of the replacement lens.

Long Eyes: People who are very nearsighted usually have eyes that are much longer than average.  This adds some difficulty with the accuracy of both the measurements and the formulas. There are special formulas for long eyes but even those are less accurate than formulas for normal length eyes.

Short Eyes: People who are significantly farsighted tend to have shorter-than-normal eyes.  Basically, the same issues hold true for them as the ones for longer eyes noted above.

Eyes with previous refractive surgery (LASIK, PRK, RK): These surgeries all change the normal shape of the cornea.  This makes the formulas we use on eyes that have had previous surgery not work as well when the normal shape of the cornea has been altered.

This is where intraoperative aberrometry comes in. The machine takes the measurements that we do before surgery and then remeasures the eye while you are on the operating room table after the cataract is removed and before the new implant is placed inside the eye. It then presents the surgeon with the power of the implant that the aberrometer thinks is the correct one.  Unfortunately, the power that the aberrometer selects isn’t always exactly right, but with the combination of the pre-surgery measurements and the intra-surgery measurements the overall accuracy is significantly enhanced.

The intraoperative aberrometry is also very helpful in choosing the power of specialty lenses like multi-focal and toric lenses.

We would encourage you to consider adding intraoperative aberrometry to your cataract surgery procedure if you have either a long or short eye (usually manifested as a high prescription in your glasses) or if you have had any previous refractive surgery.

In our modern world, people spend hours on end staring at computer screens, smartphones, tablets, e-readers, and books that require their eyes to maintain close focus.

For most people (all except those who are nearsighted and aren’t wearing their glasses), their eyes’ natural focus point is far in the distance. In order to move that focus point from far to near, there is an eye muscle that needs to contract to allow the lens of the eye to change its shape and bring up-close objects into focus. This process is called accommodation.

When we accommodate to view close objects, that eye muscle has to maintain a level of contraction to keep focused on the near object. And that muscle eventually gets tired if we continuously stare at the near object. When it does, it may start to relax a bit and that can cause vision to intermittently blur because the lens shape changes back to its distance focal point and the near object becomes less clear.

Continuing to push the eyes to focus on near objects once the focus starts to blur will began to produce a tired or strained feeling in addition to the blur. This happens very frequently to people who spend long hours reading or looking at their device screens.

An additional problem that occurs when we stare at objects is that our eyes’ natural blink rate declines. The average person blinks about 10 times per minute (it varies significantly by individual) but when we are staring at something our blink rate drops by about 60% (4 times per minute on average). This causes the cornea (the front surface of the eye) to dry out faster. The cornea needs to stay moist in order to see clearly, otherwise little dry spots start appearing in the tear film and the view gets foggy. Think about your view through a dirty car windshield and how much that view improves when you turn the washers on.

So what should you do if your job, hobby, or passion requires you to stare at a close object all day?

Follow the 20-20-20 rule. Every 20 minutes, take 20 seconds and look 20 feet into the distance. This lets the eye muscle relax for 20 seconds, and that is generally enough for it to have enough energy to go back to staring up close for another 20 minutes with much less blurring and fatigue. It also will help if you blink slowly several times while you are doing this to help re-moisten the eye surface.

Don’t feel like you can give up those 20 seconds every 20 minutes? Well if you don’t, there is evidence that your overall productivity will decline as you start suffering from fatigue and blurring. So take the short break and the rest of your day will go much smoother.