Cataract - A clouding of the lens of the eye. The normally clear aspirin-sized lens of the eye starts to become cloudy, which will eventually impair normal vision.
Cornea - The clear front window of the eye that transmits and focuses light into the eye.
Crystalline lens - A transparent, colorless body located in the front third of the eyeball, behind the iris, that helps bring rays of light to a focus on the retina.
Fovea - The central point on the retina that produces the sharpest vision.
Functional vision - The ability to see clearly while performing daily activities in varying levels of light.
Halo - Hazy ring around bright lights seen by some patients with refractive error or optical defects (e.g., cataracts or corneal swelling). This symptom may occur after surgery.
Intraocular lens - A small synthetic lens, made of a hard plastic (polymethylmethacrylate or PMMA), silicone, acrylic, or hydrogel material implanted into an eye after cataract surgery to replace crystalline lens, which has been removed.
Iris - Circular, colored portion of the eye. Its opening forms the pupil. The iris helps regulate the amount of light that enters the eye.
Monofocal IOL - An implantable intraocular lens that provides good distance and sometimes intermediate vision but doesn't correct near vision. Usually requires corrective lenses or eyeglasses after surgery for reading and near vision tasks.
Multifocal IOL - An implantable intraocular lens that is designed to provide distance and near vision simultaneously. Some multifocal IOLs also provide intermediate vision. Increased glare and halos reported at night.
Ophthalmologist - A medical doctor (MD) specializing in refractive, medical, and surgical treatment of eye diseases and disorders.
Posterior chamber - The fluid-filled space between the back of the iris and the capsular bag.
Presbyopia - A condition in which the natural crystalline lens of the eye loses its ability to "accommodate", meaning its ability to switch from seeing objects at a distance (one focal point) to seeing near objects (second focal point).
Pupil - The opening at the center of the iris of the eye that varies in diameter depending upon the brightness of the light coming into the eye.
Retina - The thin membranous lining of the rear two thirds of the eye that converts images from the eye's optical system into electrical impulses sent along the optic nerve for transmission to the brain.
Visual acuity - The clarity or clearness of the vision, a measure of how well a person sees. The ability to distinguish details and shapes of objects; also called central vision.
ReZoom® multifocal intraocular lenses are indicated for the visual correction of aphakia in adult patients with and without presbyopia in whom a cataractous lens has been removed and who desire near, intermediate, and distance vision without reading add and increased spectacle independence. These devices are intended to be placed in the capsular bag.
As with many things, there may be a trade off. If you decide to have a multifocal lens, your use of glasses may decrease, but at the cost of losing some of the sharpness of your vision. Even with glasses, this loss of sharpness may become worse under poor visibility conditions, such as dim light or fog. There may also be some visual side effects such as halos and glare from lights at night that are more common than with a monofocal IOL. Halos are rings of light that you may notice when looking directly at a source of light, such as oncoming car headlights. Glare is a scattered light effect that can appear around a source of light.
General risks with cataract surgery and IOL implantation:
Whatever your lens choice is, there are risks and possible complications of cataract surgery and lens implantation. Complications could be minor or temporary, or could permanently affect your vision. Complications are rare and may include the worsening of your vision, bleeding, or infection. Contact your eye doctor right away if you have any of the following symptoms after surgery: itching, pain, flashing lights/"floaters"/a "curtain" in your vision, redness, severe headache, nausea/ vomiting, sensitivity to light or watery eye.
Please note: warnings and precautions accompany all IOLs because they are prescription-only medical devices. The following warnings and precautions apply to all multifocal IOLs.
A very small number of patients (less than 1% in U.S. clinical studies) may be dissatisfied and request removal of their multifocal IOL. Under poor visibility conditions, your vision may be reduced more than it would be with a monofocal IOL. Under these conditions, you may have more difficulty recognizing some traffic signs and hard-to-see objects in the road. Therefore, you may need to take extra care when driving, especially in poor light conditions. In rare instances, multifocal IOLs may make some types of retinal surgery more difficult.
In a driving simulation study, under one of nine low contrast conditions, 22% more multifocal patients than monofocal patients did not notice a hard-to-see object in the road until they were closer than 100 feet (average distance for multifocal patients was 96 feet; average distance for monofocal patients was 133 feet). The distance of 100 feet is important because at speeds of 30 mph or faster, a driver may not be able to stop safely within 100 feet. In the simulation, however, drivers could also drive around objects, and there was no difference in collisions with the objects.
There is a chance that your vision may not be good enough to read small print without glasses with the multifocal IOL. Please discuss with your doctor whether this is the right lens for you. The following may affect your choice of IOL:
- In rare instances, this lens may make some types of retinal surgery more difficult.
- If the pupil of your eye is very small (less than 2.5 mm), the chances are greater that your near vision with a multifocal lens will not be better than with a monofocal lens.
- If the health of your eye makes it unlikely that your vision will be good after your cataract is removed, you may not get the full benefit of the multifocal IOL.
The most frequently reported adverse event that occurred during the clinical trial of the Multifocal lens was secondary surgical intervention (including lens repositioning, lens replacement due to biometry error or optical/visual symptoms, vitrectomy/vitreolysis, retinal repair), which occurred at a rate of 2.2%.