More recently, multifocal lenses have been developed.
Cataract surgery is usually performed under local anaesthesia.
The aim of the procedure is to allow the eye to focus on near as well as distant objects, so that the patient may not need spectacles.
Four randomised controlled trials reported significantly better distance-corrected near visual acuity for eyes with an accommodating lens than for eyes with a standard intraocular lens; follow-up ranged between 6 and 12 months.
The Institute has identified relevant audit criteria and is developing an audit tool (which is for use at local discretion), which will be available when the guidance is published.
No eyes with the standard intraocular-lens implant achieved distance-corrected visual acuity of 20/40 or better at follow-up.
The mechanism of action of accommodating lenses is unclear.
A non-randomised comparative study reported that, after 12 months' follow-up, 13% (3/24) of eyes with an accommodating lens required capsulotomy for posterior capsule opacification, compared with 25% (8/32) of eyes with a multifocal lens and 29% (7/24) of eyes with a bifocal lens (p value not reported).
An ultrasound probe is used to break the opacified lens into tiny pieces, which are removed through a small incision in the cornea (phacoemulsification).
An accommodating lens rather than a standard intraocular lens is then inserted through the incision.