In order to improve vision in a person with cataracts, the affected natural lenses in the eyes can be replaced with artificial intraocular lenses (IOLs). The natural lenses are removed and replaced with suitable IOLs. This corrective surgery is known as refractive lens exchange.
Before the introduction of IOLs, patients who had cataracts removed had to wear special contact lenses or thick eyeglasses for vision correction. This is because nothing was used to replace the lens that was responsible for focusing light on the retina. However, the introduction of FDA approved IOLs in the early 1980s has changed that.
Now, there are a wide variety of IOLs to choose from. The best lenses for you will depend on a variety of factors including your specific needs as well as your lifestyle. During consultation with your cataract surgeon, you will be provided with various options for IOLs. These may include:
1- Aspheric IOLs
These lenses differ from the traditional spherical optical design of regular IOLs since their surface is not uniformly spherical. Their shape is designed to closely mimic the shape of the natural lens. This helps to improve optical quality and avoid higher order aberrations (HOAs) that are common with spherical intraocular lenses.
Aspheric IOLs are designed to provide sharper vision particularly in conditions with low light levels. They are especially beneficial for people with larger pupils.
2 – Multifocal IOLs
These will decrease your need for computer or reading glasses after surgery. They have additional magnification in various parts of the lens to help focus images properly. Precise alignment is required for these lenses in order to provide a good visual outcome.
3 – Accommodating IOLs
These are designed to expand the range of vision of the wearer. The lens rests on flexible ‘haptics’ that allow the lens to move forward when looking at objects that are close by therefore increasing your focusing power.
4 – Toric IOLs
These lenses go a step further than simply providing a replacement for lenses removed during cataract surgery. These lenses are designed to correct vision problems, such as farsightedness, nearsightedness and astigmatism.
The lenses come with different powers. They can also be adjusted for different orientations by the surgeon when they are inserted in the eye. This helps in the correction of astigmatism.
To properly adjust the lens, the surgeon places temporary marks on the patient’s cornea. This helps the surgeon identify the parts that are most curved at the front of the eye. The surgeon is then able to rotate and adjust the IOL to line up with the markings during the implantation. This ensures proper correction of astigmatism.