During cataract surgery, the clouded natural lens of the eye is removed and an artificial lens is implanted to allow clear vision. The standard artificial intraocular lens has no focusing capability. Use of an accommodating intraocular lens is intended to allow focusing on near and distant objects, so that the patient may not require reading spectacles.

The National Institute for Health and Clinical Excellence is examining implantation of accommodating intraocular lenses during cataract surgery and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about implantation of accommodating intraocular lenses during cataract surgery.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

• comments on the preliminary recommendations
  
• the identification of factual inaccuracies
  
• additional relevant evidence.

Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that the Institute will follow after the consultation period ends is as follows.

• The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
  
• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (www.nice.org.uk/ipprogrammemanual).

Closing date for comments: 28 November 2006
Target date for publication of guidance: February 2007

Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.

Current evidence suggests there are no major safety concerns associated with the implantation of accommodating intraocular lenses during cataract surgery. There is evidence of short-term efficacy in correcting visual acuity but there is inadequate evidence that the procedure achieves accommodation. Therefore, it should not be used without special arrangements for consent and audit or research.

Clinicians wishing to undertake implantation of accommodating intraocular lenses should take the following actions.

• Ensure that patients understand the uncertainty about the procedure's efficacy and provide them with clear written information. In addition, use of the Institute's information for patients ('Understanding NICE guidance') is recommended (available from www.nice.org.uk/IPGXXXpublicinfo). [[details to be completed at publication]].
• Audit and review clinical outcomes of all patients having implantation of accommodating intraocular lenses (see section 3.1).

Publication of long-term efficacy outcomes of the procedure will be useful, particularly on the effects on accommodation. The Institute will review the procedure in due course.

A cataract is the opacification of the eye's natural lens. It usually develops over a period of time, causing a gradual deterioration in eyesight, and may eventually lead to blindness.

Surgical treatment involves replacing the patient's opacified lens with an artificial lens that is usually of fixed power (monofocal), requiring the use of reading spectacles for near vision. More recently, multifocal lenses have been developed. Cataract surgery is usually performed under local anaesthesia.

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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. In one of these studies, the difference was statistically significant at 6 months (J9.3 versus J12.4, p = 0.004) but not 12 months (J11.5 versus J12.8, p = 0.1), although the 12-month follow-up included only 67% (40/60) of eyes (the larger the J number, the lesser the visual acuity). In another of these studies, 66% of eyes (numbers not reported) with accommodating lenses had distance-corrected near visual acuity of 20/40 or better at 6 months, but this decreased to 49% of eyes at 12 months. The other two studies only reported follow-up to 6 months. No eyes with the standard intraocular-lens implant achieved distance-corrected visual acuity of 20/40 or better at follow-up.

Two Specialist Advisers considered this procedure to be a minor variation of an existing procedure. One Specialist Adviser commented that the technology is in the early stages and that more efficacious lenses are likely to be developed in the future. 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). Two case series reported capsulotomy for posterior capsule opacification in 14% (37/263) and 18% (12/65) of eyes with an accommodating lens after mean follow-up of 12 and 23 months, respectively.

One randomised controlled trial of 42 eyes reported anterior and posterior capsule opacification in 86% of eyes with an accommodating lens, compared with 25% (5/20) of eyes with a traditional lens (follow-up 12 months; p value not reported). Another randomised controlled trial of 42 eyes reported mild posterior capsule opacification in 21% of eyes with an accommodating lens and 22% of eyes with a monofocal lens after 6 months' follow-up (p value not reported).

A randomised controlled trial reported one case of intraoperative anterior chamber haemorrhage in 40 eyes (3%) with an accommodating lens. A case series reported cystoid macular oedema in 4% (12/324) of eyes with an accommodating lens over a 12-month follow-up period. Persistent cystoid macular oedema was reported in 1% (3/304) of eyes.

A non-randomised controlled trial reported halos in 8% (2/24) and flare, flashes or glare each in 4% (1/24) of eyes with an accommodating lens. Higher rates of halos, flare and glare were reported by patients with either a multifocal or bifocal lens.

The Specialist Advisers listed potential adverse events as including lens decentration, posterior capsule opacification, lens or haptics buckling, development of capsular contraction syndrome and loss of quality of vision.

It was noted that the evidence reviewed on this procedure relates to the treatment of cataract and not to the correction of presbyopia.

It was noted that the procedure is at a relatively early stage of development and that the technology of accommodating lenses is evolving rapidly.

This guidance requires that clinicians undertaking the procedure make special arrangements for audit. 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.

The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.

• 'Interventional procedure overview of implantation of accommodating intraocular lenses during cataract surgery', August 2006.