Cataract surgery is one of the most common eye surgeries performed, and most of us, or a family member, will need this surgery eventually! Many people will notice the symptoms of their cataracts after age 60, although some people can be bothered by the glare, halos, and blurry distance vision much earlier.
Cataract surgery involves removing the natural lens of the eye and replacing it with a new, clear lens. This new lens is called an IOL, or “intra ocular lens”. How do the surgeons know what IOL to put in the eye? Figuring that out starts with a discussion to find out how you would like to see after surgery.
Conventional monofocal IOLs have only one power available in the lens. The monofocal IOL has a single focal length. Many patients choose this option with the focal length of the lens set for distance in both eyes. The result is great distance vision without glasses. However, with this option you will need reading glasses to see up close. Because the IOL focuses only in the distance, and cannot focus up close, the “cheater” glasses are a must. Some patients prefer to fill a bifocal glasses prescription after surgery, even though they see well in the distance, for convenience. Even though reading glasses will be needed after surgery, you will still be far less dependent on glasses than in the past.
Monofocal IOLs can be used to focus at any distance you would like. If you have always been nearsighted, and enjoy being able to read or sew up close without glasses, you may choose to have the IOL power set for near. With an IOL set for near, near tasks require no glasses, but correction would be needed for distance tasks.
Monofocal IOLs can also be used in a “mono vision” fashion. This option has the focal length of one eye set for distance, and the other for near. Many people who choose this option have already used mono vision contact lenses and know that it works for them. Mono vision results in far less dependence on glasses, with one eye seeing in the distance and one eye seeing to read. Not everyone’s brain likes mono vision however! It’s best to try it first in contact lenses to see if it’s right for you. With this option sometimes patients will use glasses at night to drive.
Conventional monofocal IOLs are covered by insurance. The following options typically are not covered by insurance. These IOLs are paid for out of pocket.
Toric IOLs correct astigmatism, or atypical shape of the front of the eye. Astigmatism creates 2 different focal lengths in the eye. A conventional monofocal IOL can only focus in one spot, therefore it will not correct astigmatism. If you have astigmatism and a monofocal lens is implanted, glasses will still be needed for distance and near. A toric IOL will correct this, it has 2 different focal lengths.
Presbyopia Correcting IOLs
Presbyopia correcting IOLs are also a great option, resulting in the most freedom from glasses. Right around age 40 the lens inside the eye loses the ability to focus up close, called presbyopia. Presbyopia results in needing reading glasses or bifocals. A presbyopia-correcting IOL focuses at distance and near. There are several different lens options in this category, enough to fill a whole blog! As a matter of fact, Dr. Graham wrote a great blog about the Symfony lens.
It’s important to know these IOLs are available, and talk to your surgeon to see which is right for you.
So, you’ve decided what IOL you want, how do eye doctors know what lens power to use? That is where our technicians come in. Relf EyeCare has an awesome team of certified ophthalmic assistants and technicians that use state of the art equipment to measure the eye. It is checked and rechecked, then the surgeons use these calculations and the results of their eye exams to decide on the perfect lens for your eye. These measurements are taken at your cataract evaluation, and repeated if necessary, until our very particular staff is happy with them.
Relf EyeCare’s surgery team carefully tracks outcomes and is constantly striving to be perfect.
Hopefully this sheds a bit more light on cataract surgery IOL options and measurements. Next time, we’ll discuss what to expect after surgery, recovery time, insurance coverage and cost of cataract surgery.