Monofocal lens
These lenses are the most commonly implanted lenses today. The Monofocal lenses are available both as Rigid or Foldable lens. They have equal power in all regions of the lens and can provide high-quality distance vision, usually with only a light pair of spectacles. Monofocal lenses are in sharpest focus at only one distance. They do not correct pre-existing astigmatism, a result of irregular corneal shape that can distort vision at all distances. Your surgeon may correct the astigmatism at the time of cataract surgery by making one or two additional incisions in the periphery of the cornea. This does not make the surgery more dangerous. People with significant astigmatism require corrective lenses for sharpest vision at all distances. Patients who have had monofocal intraocular lenses implanted usually require reading glasses.
Aspheric intraocular lens
The standard traditional monofocal lens has a front surface that is uniformly curved or 'spherical'. In contrast, aspheric lenses have a flatter periphery. This design helps to improve contrast sensitivity, reduce optical aberrations, and make the vision crisper.
Blue light-filtering intraocular lens
Some of the newer implants have been manufactured to have a yellow tint to provide blue light protection. This is to mimic the original lens which naturally filters these potentially harmful rays. Blue light ranges from 400 to 500 nanometers, and is present in natural and artificially produced light. Theoretically, minimizing entry of blue light into the eye reduces the risk of damage to the macula, such as in age-related macular degeneration.
Toric lens
Toric lenses have more power in one specific region in the lens to correct astigmatism as well as distance vision. Due to the difference in lens power in different areas, the correction of astigmatism with a toric lens requires that the lens be positioned in a very specific configuration. While toric lenses can improve distance vision and astigmatism, the patient still will require corrective lenses for all near tasks, such as reading or writing.
Multifocal lens
Multifocal intraocular lenses are one of the latest advancements in lens technology. These lenses have a variety of regions with different power that allows some individuals to see at a variety of distances, including distance, intermediate, and near. While promising, multifocal lenses are not for everyone. They can cause significantly more glare than monofocal or toric lenses. Multifocal lenses cannot correct astigmatism, and some patients still require spectacles or contact lenses for clearest vision. The main minor complaints from multifocal lenses are: glare, halos, and mild starbursts around light sources at night.
Accommodating intraocular lens
This lens also allows you to see well at more than one distance without glasses or contact lenses. It is designed with a hinge similar to the mechanics of the eye's natural lens. This hinge allows back and forth movement of the implant, thereby giving natural focusing ability at different distances. Some have suggested that the reading focus for the accommodating intraocular lens may not be as strong as the multifocal intraocular lens. There is also the concern that these lenses are only able to retain the near vision capability over a period of a few months rather than years.
Choosing your intraocular lenses
Many important factors will affect which intraocular lenses are the right choice for you, including:
Are you nearsighted or farsighted?
Do you also have any astigmatism?
How do you feel about continuing to wear glasses or contact lenses after your cataract surgery? Would you prefer not to need glasses or contacts after surgery?
How important is good night vision to your lifestyle?
In general, how well do you adjust to changes and learn new skills?
Your doctor may also ask you:
What activities or tasks are necessary to your daily life? To your job?
What hobbies do you currently enjoy or would like to engage in most often?
During which activities would you find glasses the most inconvenient or aggravating?
Standard Monofocal intraocular lenses are an excellent choice if you:
Don't mind wearing glasses or contact lenses for most distances
Do not have astigmatism or are willing to address your astigmatism by wearing corrective
lenses or by having additional surgeries such as LASIK or limbal relaxing incisions.
Are less comfortable adapting to change and learning new skills.
Wish to avoid a possible increased risk of some night vision symptoms
Toric intraocular lenses are an excellent choice if you:
Have astigmatism as well as cataracts.
Don't mind wearing glasses or contact lenses for some distances.
Are less comfortable adapting to change and learning new skills.
Multifocal intraocular lenses are an excellent choice if you:
Want to reduce your dependence on glasses or contacts as much as possible.
Do not have astigmatism or are willing to address your astigmatism by wearing corrective lenses or by having additional surgeries such as LASIK or limbal relaxing incisions.
Are less comfortable adapting to change and learning new skills.
Are willing to risk some minor night vision symptoms Wish to avoid a possible increased risk of some night vision symptoms
Monovision
Normally, a monofocal lens such as a standard or toric intraocular lens will give you excellent near or distance vision, but not both. But with a technique called monovision, you may be able to obtain good vision of both near and far objects using these lenses.
With IOL monovision, one eye receives a lens for distance vision, while the other receives a lens for near vision. Once you've adjusted to monovision, your brain effortlessly selects the image you want to see at each moment, so you see well at near and far distances.
If you haven't tried monovision before but are interested in this approach, your doctor can help you try monovision in advance using specialized contact lenses. This is an important step to confirm you would be able to adjust easily.
IOL monovision is an excellent choice if you:
Want to reduce your dependence on glasses or contacts as much as possible.
Are comfortable adapting to change and learn new skills easily.
Wish to avoid a possible increased risk of some night vision symptoms
If you have any astigmatism, the same effect can be achieved with toric IOLs. Whether or not you have astigmatism, monovision can be an excellent way to combine the benefits of two different lenses.
