Vision occurs when light is focused by the lens onto the retina (light-sensitive tissue at the back of the eye). The ability of the lens to change its curvature helps us see clearly. As we age, the lens may become less flexible or cloudy and require replacement of the faulty lens with a new lens to restore clear vision.
These conditions were previously corrected by surgically inserting monofocal lenses, in which either near or far vision was corrected, and required patients to wear reading glasses for complete vision. Multifocal lens implants, also known as intraocular lenses (IOL), are surgically inserted into the eye to provide good vision of near, intermediate, and far objects. They have many concentric circles that act as multiple focal zones and can provide you with clear vision at various distances.
Multifocal lens implants are indicated for presbyopia (age-related dysfunction in the focusing power of the lens), cataracts (clouding of the lens), and for those who do not want to wear reading glasses or contact lenses.
Multifocal lens implant surgery is performed on an outpatient basis under local anaesthesia. Eye drops will be placed in your eyes to dilate your pupil. Your surgeon will make a small incision in the cornea (transparent dome-shaped surface of the eye), break up the defective lens using a probe that passes ultrasound waves, and remove its fragments (phacoemulsification). Sometimes, when you have certain other complications with your eyes, your surgeon may suggest extracapsular cataract extraction, during which a larger incision is made and the front portion of the lens is removed, leaving the back portion intact. However, this procedure is not done very often.
Following either of these methods, an artificial multifocal lens will be implanted in place of the defective lens, which will become a permanent part of your eye. You may or may not require stitches for closure depending on the size of the incision on the cornea.
The procedure is done on one eye at a time. The other eye is corrected only after the first has healed.
After a multifocal lens implantation, your vision will begin to improve gradually. You will be provided with instructions on eye care. Some mild itching and discomfort may be present for the first few days. You should avoid rubbing or applying pressure on your eyes. You will be prescribed medications and eye drops to reduce your discomfort and to prevent infections. Your doctor may advise you to use a patch over your eye at night until healing occurs. Complete healing will occur within eight weeks. But, some patients may have problems with night vision (viewing rings around lights at night time) until the brain adjusts to the new multifocal intraocular implant. You will need to follow up with your eye doctor in one or two days.
Complications after multifocal lens implantation are fairly uncommon and occur mostly if you have some other serious medical condition or eye disease. Some of these possible complications include:
The benefits of multifocal lens implantation include:
Multifocal lens implantation is a widely known and fairly safe procedure, which can result in improved vision and better quality of life. Your candidacy will depend on your overall health and the condition of your eyes, and your eye doctor will be the best person to advise you on the procedure.