Before the development of intraocular lenses (IOLs), people needed to wear thick eyeglasses or special contact lenses to see after cataract surgery. However, today several types of IOL implants are available that help people to improve their vision, often reducing their dependence on spectacles post surgery.
Similar to the natural lens of the eye, an IOL focuses the light passing through the cornea and pupil on the retina. Most of the IOLs used today are made up of flexible and foldable material and are approximately a quarter of an inch in size when open and placed inside the eye, but are inserted through tiny incisions (by rolling or folding the implant). These incisions are about 2 mm wide, which is like the thickness of a coin. This allows the eye to heal very quickly after the operation. Similar to the prescription of eyeglasses, IOLs contain the right prescription to give the best vision.
Before surgery, your eyes are measured to determine the IOL prescription, a process termed biometry. Depending on how you feel about wearing glasses, your lifestyle needs and the overall condition of your eye including your spectacle prescription and any co-existing eye conditions, Dr Somdutt Prasad will discuss the best IOL type for you. Remember this is an individualized choice, and we aim to empower you to make the right decision by providing you with all the choices which are suitable for you, so that you can decide the best option for yourself with advise from your doctor. The type of IOL will affect your vision when you are not wearing eyeglasses. If you have astigmatism, then Dr Somdutt Prasad will discuss about toric IOLs and the related treatment options.
Monofocal lens is the most common type of IOLs used that has been available for several decades. This IOL provides the best-corrected vision at near, far or intermediate distances. Most people using monofocals choose to have their IOL power for distance vision and use normal reading glasses for near activities.
Multifocal lenses greatly reduce the need for contact lenses or glasses after implantation. In this type of lens, a series of rings or focal zones are designed into the IOL. Depending on the focus of the incoming light through the zones, one can see both distant and near objects. Most people with multifocal IOLs are functionally spectacle independent. They can do most activities without glasses but may need glasses occasionally for some visual tasks. For example, they may be more comfortable with reading glasses when settling down to read a book, but be able to read without glasses when reading short passages. Thus the need for spectacles is greatly reduced but may not be entirely eliminated.
This type of IOL is recommended for people with astigmatism. This is the ‘Cyl’ or cylindrical part of your spectacle prescription. Astigmatism is a condition that blurs or distorts the ability to see distant and near objects. This cylinder can be incorporated into the IOL implant so that your distance vision can be much clearer without glasses after surgery than it would have been if a standard monofocal IOL was implanted.
In a few cases, even after healing from cataract lens surgery, people may need additional correction to achieve the best vision. In such cases, ophthalmologists may advocate an extra surgery to exchange an IOL with another type or implant an additional one. In some cases, laser refractive surgery may be recommended.
People who have had LASIK surgery need to be evaluated carefully before getting IOLs as the previous surgery may affect the ability to calculate correct IOL prescription. So it is very important to tell your eye surgeon about any previous eye surgery you may have had.
These premium IOLs involve special manufacturing and diagnostic processes so will usually cost more than surgery with a monofocal lens because of the higher cost of the implant.
Dr Somdutt Prasad, one of the best retinal specialists and a top eye surgeon in Kolkata, has extensive experience regarding usage of IOLs and more than 90% patients undergoing the procedure have been spectacle independent. At i4vision, a top-notch eye care clinic in Kolkata, several patients have undergone successful IOL implants by Dr Prasad.