So you note symptoms of decreased vision and glare. Your ophthalmologist determines cataract surgery is required to improve your visual function. What additional information do you require to make an informed decision about your cataract surgery?
As our Hamilton eye doctors can attest, cataract surgery has improved drastically over the past 3 decades. Two advancements have been the vanguard of this revolution: small incision surgery and the refinement of the intraocular lens (IOL).
Cataracts can now be removed using incisions less than one-tenth of an inch across. Surgical microscopes, a vibrating needle to break up the lens (phacoemulsification), and foldable intraocular lenses make this miracle a daily reality. These instruments in an experienced surgeon’s hands provide rapid, painless vision recovery.
The type of intraocular lens implanted at the time of your cataract surgery will determine how often you will require glasses to perform your daily tasks. The greater your understanding of these choices, the more productive your preoperative discussion with our Princeton-area ophthalmologists will be. The choice of lens implant will determine how frequently and under what circumstances you will require glasses following your surgery.
The lens in the eye sits behind the iris (i.e., the colored part) and along with the cornea, it is responsible for focusing the light on the retina.
Current IOLs are miracles of modern science; however, even the most advanced lens does not match the phenomenal capabilities of the natural crystalline lens that you were born with. Your native lens, in its youth, could effortlessly change power to bring whatever you chose to view into focus instantly.
As the lens becomes more rigid and inflexible with time, it can no longer change its focus easily, leading to the need for reading glasses or bifocals some time in the mid-forties. As the lens ages, it becomes cloudy — and when it begins to obscure the vision, then it is considered a cataract.
When this lens is removed during cataract surgery, a new lens must be implanted — much like if you removed a lens on a camera, you would have to put a new one on before you could expect to take a photo.
When deciding which lens is ideal for you, consider the following:
- How important is it for you to minimize your need to wear glasses?
- Is it more important to you to perform near tasks, like reading or distance tasks, such as driving and watching TV.
Current lens choices:
- Monofocal Lens: This is the most versatile and most widely implanted lens by far. It has a single refractive power. Measurements of your eye are taken to determine the power of the implant needed to give you the desired refractive result. A popular choice with the monofocal lens is monovision. With monovision, a monofocal lens is used to allow one eye to see distance and one eye to see near. This allows for most tasks to be done without spectacles. If better vision is required (for driving at night, for example) glasses can be used for those more demanding situations.
- Toric Lens: The toric lens addresses astigmatism. The astigmatic error due to the cornea is not alleviated with cataract surgery. A toric lens has different refractive power, along different portions of the lens. This lens has to be lined up with the axis of the patient’s corneal astigmatism. Correcting the astigmatism with the toric lens allows patients with corneal astigmatism to be more spectacle independent. This lens can also be used for monovision.
- Multifocal Lens: These implants use the optical principle of diffraction to divide the incoming light, providing both a distance and near focal point. Using this lens, both eyes can be set up in a similar fashion, and both eyes can function at both distance and near. Since the light is divided into two focal points, there is some degradation of the quality of the image, and this can decreased contrast sensitivity, a more sensitive measure of vision. These lenses also produce significantly more glare at night — so if night driving is an important task, these lenses are not ideal. The optical aberrations produced by these lenses cannot be corrected by simply wearing glasses. Recently, extended range of focus lenses have been introduced as variants of multifocal lenses that attempt to minimize the downsides of a multifocal lens.
Only you can determine when or if you would like to be spectacle independent after cataract surgery. The evaluation and discussion with your ophthalmologist will determine what is ideal for you.
Cataract surgery is indeed a modern miracle. Choosing the correct implant for you will ensure you get the most out of your surgery.