A focusing lens implant is typically placed in the eye at the time of cataract surgery. Traditionally a monofocal lens is inserted and is standard practice in the NHS. Unfortunately a standard monofocal lens will not correct astigmatism, nor provide good depth of focus with a clear image at near, intermediate and distance. A variety of “added value” lenses are available and include:
- Monofocal Toric Lens – to correct astigmatism
- Trifocal Lens – to correct distance, intermediate and near
- Trifocal Toric Lens – also corrects astigmatism
- Accommodative Lens – improve depth of focus by moving in the eye
Monofocal Toric Lens
This is a lens that corrects astigmatism in those who have a high amount. Like an astigmatic spectacle or contact lens, astigmatism correction is built into the implant. The lens implant which needs to be sepcially ordered, is inserted into the eye and accurately positioned at a specific astigmatic angle. This implant provides patients with good vision correction at distance. For near and intermediate vision, glasses are usually necessary.
This exciting implant in regular use at Centre for Sight since January 2011 reliably corrects distance, intermediate and near vision. TWO trifocal lenses are used at Centre for Sight. The FINEvision by Physiol and the AT-Trifocal by Zeiss. Both lenses work on similar principles and reliably eliminate the need for glasses altogether. Some patients need to go through a period of adaptation – and have to get used to using the lenses. More information on Trifocal lenses is available by clicking here.
Trifocal Toric Lens
For those who have large levels of astigmatism (1.75D or more), a toric lens is required. Fortunately these are also available with Trifocal lenses and have to be ordered specially for each individual eye. Like the monofocal toric, the lens implant has to be placed in the eye at the correct angle to neutralise corneal astigmatism. The lenses reliably provide spectacle freedom for distance, intermediate and near vision.
This is a lens that moves in the eye and in doing so, like the natural lens we are born with provides a change in focusing power. This allows patients to see at intermediate and near. The Crystalens accommodative implant has been used by Centre for Sight surgeons since 2002. The lens is very popular in the USA and has an extremely good optic. The disadvantage of the lens is that does not reliably correct near vision and many (30%) of patients still need glasses for fine print after surgery. For more detailed information on the Crystalens and Accommodative lenses click here.