My Handy Toric IOL Trick

Hawaiian Eye 2014

Roger F. Steinert, MD


February 11, 2014

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Hi. I'm Dr. Roger Steinert, Chair of Ophthalmology and Director of the Gavin Herbert Eye Institute at the University of California, Irvine. I'm reporting from the Hawaiian Eye meeting in beautiful Kauai, Hawaii.

We just had a full session on issues in cataract surgery. I would like to share my own presentation from that session. It has a trick that I think you will find useful.

How do you figure out where a toric intraocular lens (IOL) actually is? Postoperatively, if you are not getting the results that you want, you think maybe the IOL is out of position, but where is it?

Most slit lamps have a slit beam that can be rotated. You rotate the light tower at the top, and the narrow beam will rotate from vertical to any position that you rotate the light tower. You can take that beam and align it across the marks on the toric IOL.

Then, it's still a question of, where is it? Most slit lamps don't have any narrow markings of sufficient resolution to be useful at the top of the light tower, because you want to know down to 1° or 2° where that implant actually is.

I have discovered that you can go to the App Store and find about a dozen apps for carpenter's levels, which are designed for hanging pictures and so forth -- but you can use them to your advantage. You can take that slit beam that you have angled across the markings on the toric IOL and align that with the edge of your smartphone, and it will tell you the degree position of the toric IOL.

The app that I use (and I have no proprietary interest) is called the iHandy Level. When you rotate it, you can see that the degree markings change. Sometimes you have to do a little math, because you get a negative or positive number depending on how it is oriented, but the iHandy Level can tell you where the IOL is oriented if you take the slit beam and line it up on one of the edges -- for example, the superior edge. You can then figure out where the implant is. Most of the time, there is no doubt where you want it to be -- which is on the steepest meridian, based on keratometry.

If you want to know how much error the current position is creating, a very handy Website is -- created by Dr. John Berdahl and Dr. David Hardten -- which automatically performs the vector analysis for you and will tell you how much error is being created by your current lens. If there is any doubt about where to put the lens, it will tell you which orientation gives you the smallest amount of residual astigmatism. I highly recommend that as well.

I hope this trick has been useful to you. Happy hunting at the App Store.

This is Dr. Roger Steinert on behalf of Medscape. Thanks for listening.


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