Cataract Surgery after LASIK III: Should I Treat Presbyopia?
This article is the third in a series about cataract surgery after LASIK. These articles help you understand how LASIK changes the eye, and how this affects your postoperative experience with cataract surgery. In this article I will address presbyopia correction in the post LASIK eye.
Presbyopia can be treated during cataract surgery with advanced technology lenses. These fall into two classes. Multifocal lenses (MF) provide two focal points, one at distance and the other at near or intermediate. Extended depth of focus lenses (EDOF) provide a greater depth of focus, allowing moderate near vision to be achieved even though the eye is primarily focused at distance. For the rest of this article, the two types of lenses will be discussed together using the term MF/EDOF lens.
There are three reasons you should be cautious about choosing MF/EDOF lenses if you have had LASIK.
First, the side effects of the MF/EDOF lenses are similar to those of LASIK, including glare, halos, and loss of contrast. MF/EDOF lenses have the potential to make these side effects clinically apparent, or more prominent, in the post LASIK eye.
Second, the refractive outcome after cataract surgery is harder to predict in the post LASIK eye. The distance at which the lens focuses may be different than intended, and there may be some amount of unpredicted astigmatism. Residual refractive issues after cataract surgery degrade the performance of the MF/EDOF lenses and increase the prominence of the side effects.
Third, dry eye is often present in the post LASIK eye, and cataract surgery can make dry eye worse. Dry eye causes a blurring of vision and loss of contrast, which can degrade the performance of the MF/EDOF lenses.
Does this mean you should not consider a MF/EDOF lens if you have had LASIK? Not necessarily. You might still qualify. But you should make your decision carefully based on the factors listed below, and discuss each of these with your surgical team:
1. Your personality. Are you flexible and easy going by nature?
2. Pathology: Is there anything else about your eye that might make a MF/EDOF lens perform poorly? Examples include issues with your cornea, dry eye, and loose eyelids. Inside the eye, you should be sure that you have a good macula and optic nerve, with no history of macular degeneration and no glaucoma or any other optic nerve disease.
3. Physique. Taller is better, as taller people have the option of holding things a little further away to read, which is advantageous with the MF/EDOF lenses.
4. Predispositions. MF/EDOF lenses are distance dominant. Do you like to make crafts, spend your day reading, or doing other detailed near work? The MF/EDOF lenses may less suited for you than if you enjoy sports and the great outdoors.
In addition to the above considerations, go back in your records and determine how nearsighted you were before your LASIK. If your refraction was smaller than -3.00 Diopters, then the likelihood that you will experience unwanted side effects goes down. However, if before your LASIK your glasses or contact lens prescription was greater than -6.00 Diopters, the risk of side effects with the MF/EDOF lenses goes up.
Finally, consider what your surgeon offers. Does your surgeon have the technology to allow them to do their best refractive work? Look for a practice with the newest generation systems for measuring the eye. There are a number of state of the art assessment systems. The most common ones in the US are the Zeiss IOLMaster 700 and the Lenstar LS900. Also, does your surgeon have intraoperative aberrometry (ORA) available? This technology allows the surgeon to refine refractive decisions in the middle of your surgery, when more information is available. Finally, what is your surgeon’s plan if things don’t come out perfect? Can they touch up your LASIK to refine your refractive outcome? Are they willing to consider a lens exchange? If these things are advised, how much will they cost you?
In summary, if you have had LASIK, be cautious about choosing MF/EDOF lenses. It still may be possible to choose MF/EDOF lenses, but consider each of the above issues before making your final decision.