12. What is an Intraocular Lens?
An intraocular lens or an “IOL” is an artificial lens, made of a special type of bio-compatible plastic material, which is implanted in the eye, in place of the natural lens during cataract surgery. Cataract surgery is necessited to remove the cloudy natural lens. However, since the natural lens of the eye has a focusing power, its absence can lead to a large error in the focusing power of the eye, leading to thick “Soda-Water Bottle” type glasses. To avoid this problem, an intraocular lens is implanted in the eye during cataract surgery. After the implantation of the intraocular lens, the likelihood that the person will need spectacles after cataract surgery for distance vision is reduced.
13. What are the different types of Intraocular Lenses available to me?
Intraocular Lenses (IOLs) can be of many different types, with various costs. To summarize the cost structures, there are five types of lenses:
a) Fixed, Rigid Lenses
b) Foldable Lenses
c) Aspheric Foldable Lenses
d) Accomodative Foldable Lenses and
e) Multifocal Foldable Lenses
Fixed rigid lenses were ok for an older type of cataract surgery, but because phacoemulsification surgery can be done with small incisions, fixed lenses are not good enough, since they need a large incision to go through. This removes some of the advantages of phacoemulsification surgery. Therefore foldable lenses are used.
Foldable lenses are just that. They can be folded, like a roti, so that the lens can be put inside the eye through a small incision. Once in the eye, they are unfolded, so that they become circular. Foldable lenses can typically be put in the eye through incisions as small as 2.8 mm. In face, special lenses, like MICS lenses, can even go in through the eye through sub-2 mm incisions.
The other three types of lenses are all foldable, but differ from ordinary IOLs in their optical properties. Aspheric lenses can minimize the fine aberrations of the eye, and lead to better contrast, especially in the night. Accomodative lenses and multifocal lenses, like the Crystalens or the Restor Lens, can be implanted if the patients want excellent vision both for near vision as well as for distance vision.
For answers to more questions regarding cataract surgery, please visit the Cataract Surgery Page.