Cataracts are one of the leading causes of vision impairment worldwide; cataract surgery being the only effective means of treatment.
Cataract surgery involves removing the cloudy cataract lens and replacing it with an artificial intraocular lens (IOL). There are many types of IOLs available; the choice of which can grant you varying visual outcomes after surgery!
This blog aims to explore the various types of IOLs available and their varying visual benefits to help you decide which lens is right for you.
An intraocular lens (IOL) is a tiny, artificial lens that replaces your natural cataract lens during cataract surgery. It is made from silicone, acrylic, or other plastic materials, and coated with a special material to protect your eyes from ultraviolet light.
Intraocular Lens (IOL)
Monofocal lenses allow for clear vision at a single distance. This can be at close distances (e.g. for reading), middle distances (e.g. for computer screens) or far distances (e.g. for driving or golf). If you attempt to look at distances nearer or farther than your set distance, your vision may be blurry and you may require additional glasses to see clearly for these tasks.
Multifocal lenses allow for clear vision at multiple distances. These lenses offer you the most visual freedom and are useful if you desire clear vision at both near, far and intermediate distances without the need for additional glasses. The lens is very different to the multifocal lenses in glasses and works by focusing light at multiple focal points in the eye.
However, this increase in focusing distances comes at a higher risk of side effects such as glare and halos around lights. Some patients are more sensitive to this than others; as such multifocal lenses are not tolerable by everyone.
EDOF lenses are the latest advancement in IOLs, combining the benefits of both monofocal and multifocal lenses. It allows clear vision at both intermediate and far distances (i.e. from your computer screen to vision for driving). This lens works by creating a single, yet elongated focal point. As such, it reduces the risk of glare and halos that come with multifocal lenses.
Monofocal and multifocal lenses can also come in toric forms. Toric lenses are able to correct astigmatism as well as short sightedness and long sightedness. Astigmatism is caused when the front surface of the eye (cornea) or less commonly, the lens inside your eye, is irregularly shaped. When the eye has an irregular curvature, this causes light that enters your eye to refract in different directions at multiple focal points, rather than at one singular focal point.
Monovision is not a type of IOL. Rather, it is a technique that allows for good vision at different distances. One eye has an IOL that allows for clear vision at one distance (near) and the other eye has an IOL that allows for clear vision at another distance (far). Out of one eye, you can see clearly at near distances, and from the other eye, you can see clearly at long distances such as for driving. Monovision may sound complicated, but most patients are able to adapt to this visual technique. After a period of adaptation, our brain is able to differentiate between near and far images automatically.
In saying that, not all patients are able to adapt to monovision, so you may need to trial this technique by using contact lens. Additionally, monovision may not be suitable for those who require good depth perception which is required for some occupations.
Ultimately the IOL you choose is a highly personal choice, depending on your individual lifestyle factors and specific visual requirements.
Some questions to think about to help you in your decision include:
We understand that the choice of which IOL to use can be difficult and overwhelming at times.
Our team of highly qualified eye specialists at George Street Eye Centre are cataract specialists who are able to help you with your IOL choice. If you would like more information, please call us on (02) 9230 0010.