What are Intra Ocular Lenses (IOLs) ?
Intraocular lens (IOL) is a lens implanted in the eye used to treat cataracts or myopia. The most common type of IOL is the pseudophakic IOL. These are implanted during cataract surgery, after the cloudy crystalline lens (otherwise known as a cataract) has been removed.
As well as the calculated power for correction of the refractive error, IOLs usually come in different filters and colors to protect the eye from the UV rays.
IOL and your vision
Just like your glasses, IOL power is calculated in a way that reduces the need for glasses and provides the patient with clear vision at distance or near, depending on the IOL type. With new generation of Multifocal and Tori IOLs, both astigmatism and presbyopia can be corrected.
IOL Surgeries
(IOLs) are implanted inside the eye to replace the eye's natural lens when it is removed during cataract surgery.
IOLs also are used for a type of vision correction surgery calledre fractive lens exchange.
Types of IOL
- Monofocal IOLs
Monofocals are set to provide best corrected vision at near, intermediate or far distances.
Most people who choose monofocals have their IOLs set for distance vision and use reading glasses for near activities. On the other hand, a person whose IOLs were set to correct near vision would need glasses to see distant objects clearly.
- Multifocal or accommodative IOLs
In the multifocal type, a series of focal zones or rings is designed into the IOL. Depending on where incoming light focuses through the zones, the person may be able to see both near and distant objects clearly.
The design of the accommodative lens allows certain eye muscles to move the IOL forward and backward, changing the focus much as it would with a natural lens, allowing near and distance vision.
- Toric IOLs
This is a monofocal IOL with astigmatism correction built into the lens .
Like toric soft contact lenses for astigmatism, toric IOLs have different powers in different meridians of the lens to correct the asymmetric power of the eye that is characteristic of astigmatism.
Cataract surgery with a toric lens implant (IOL) is essentially the same as cataract surgery with a conventional IOL, but with a couple of important differences.
Prior to surgery, measurements are taken to enablecataract surgeonsto choose the most beneficial toric IOL power and the required orientation of the implant in the eye to correct the astigmatism successfully.
Toric IOLs have special markers on the peripheral parts of the lens that enable the surgeon to see the orientation of the astigmatism correction in the lens. Once the toric IOL is implanted in the eye, the surgeon then rotates the lens so the astigmatism correction is properly aligned for best results.
Use of a toric IOL during cataract surgery does not increase the risk of commoncataract surgery complications, but a misaligned toric IOL can cause blurred vision that cannot easily be corrected with eyeglasses or contact lenses.