Tenotomy of horizontal eye muscles for nystagmus (with reattachment at their original insertions)(interventional procedures second consultation)

NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE

Interventional procedure consultation document

Interventional procedure overview of tenotomy of horizontal eye muscles for nystagmus (with reattachment at their original insertions)

Nystagmus is the involuntary movement of the eyes (most commonly from side to side) and is usually associated with impaired vision. Tenotomy involves cutting the horizontal muscles of the eye (which move the eye from side to side) and reattaching them at the same place. The aim of the procedure is to improve vision.

 

The National Institute for Health and Clinical Excellence (NICE) is examining interventional procedure overview of tenotomy of horizontal eye muscles for nystagmus (with reattachment at their original insertions) and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. NICE'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 tenotomy of horizontal eye muscles for nystagmus (with reattachment at their original insertions).

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 provisional recommendations
  • the identification of factual inaccuracies
  • additional relevant evidence, with bibliographic references where possible.

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

The process that NICE 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  • The Advisory Committee will then prepare draft guidance which will be the basis for NICE's guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.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 NICE website (www.nice.org.uk/ipprogrammemanual).

NICE is committed to promoting through its guidance race and disability equality and equality between men and women, and to eliminating all forms of discrimination. One of the ways we do this is by trying to involve as wide a range of people and interest groups as possible in the development of our guidance on interventional procedures. In particular, we aim to encourage people and organisations from groups in the population who might not normally comment on our guidance to do so. We also ask consultees to highlight any ways in which draft guidance fails to promote equality or tackle discrimination and give suggestions for how it might be improved. NICE reserves the right to summarise and edit comments received during consultations, or not to publish them at all, where in the reasonable opinion of NICE, the comments are voluminous, publication would be unlawful or publication would otherwise be inappropriate.

Closing date for comments: 24 February 2009

Target date for publication of guidance: May 2009

 

1 Provisional recommendations
1.1 The evidence on tenotomy of horizontal eye muscles for nystagmus (with reattachment at their original insertions) raises no major safety concerns, but current evidence on its efficacy is inadequate in quantity. Therefore, this procedure should only be used with special arrangements for clinical governance, consent, and audit or research.
1.2

Clinicians wishing to undertake tenotomy of horizontal eye muscles for nystagmus (with reattachment at their original insertions) should take the following actions.

  • Inform the clinical governance leads in their Trusts.
  • Ensure that patients and their carers understand the uncertainty about the procedure's efficacy and provide them with clear written information. In addition, the use of NICE'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 tenotomy of horizontal eye muscles for nystagmus (with reattachment at their original insertion) (see section 3.1).
1.3 Patient selection and follow-up should take place in specialist units with experience in the management of ocular motility disorders.
1.4 NICE encourages further collaborative data collection, including information on visual acuity and quality of life, and may review the procedure on publication of further evidence.

 

2 The procedure
2.1 Indications and current treatments
2.1.1 Nystagmus is an involuntary oscillatory movement of the eyes, usually from side to side, but sometimes the eyes move up and down or in a circular motion. Most people with nystagmus have impaired vision.
2.1.2 There are several types of nystagmus but there is no definitive classification system to describe them. Nystagmus may be present at birth, caused by defects in the eye or the visual pathway from the eye to the brain. It can occur in a wide range of childhood eye disorders and may be found in children with multiple disabilities or conditions such as Down's syndrome. Nystagmus can also develop later in life as a symptom of a variety of conditions, including stroke, multiple sclerosis or head injury.
2.1.3 There is currently no curative treatment for nystagmus. Spectacles or contact lenses may be worn to improve visual acuity but these do not correct the nystagmus.

 

2.2 Outline of the procedure
2.2.1 Tenotomy for nystagmus is carried out under general anaesthesia, and involves division of the attachments the two horizontal rectus muscles (lateral and medial) of each eye. A limbal incision is made in the conjunctiva and each muscle is detached from the sclera. The muscle is then reattached at its original place of insertion.
2.2.2 The aims of the procedure are to reduce the frequency and amplitude of nystagmus (how often and how far the eyes oscillate) and to improve visual acuity

 

Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview, available at www.nice.org.uk/IP704overview.

 

2.3 Efficacy
2.3.1 In a case series of 10 adults treated with tenotomy, 9 patients had increased eXpanded Nystagmus Acuity Function (NAFX) scores at 1 year (this score is an objective measure used to predict visual acuity on the basis of the patient's foveation period, defined as their ability to fix an image on the fovea or the most visually precise part of the retina). One patient had a decreased NAFX score. A case series of 9 patients with infantile nystagmus reported that 8 patients had increased nystagmus acuity function scores (mean 60%) at 1 year. The acuity function score remained unchanged in 1 patient at 1 year. All 9 patients had reduced nystagmus amplitude (mean 33%) and increased foveation period (mean 104%) at 1 year. In a case series of 5 children with infantile nystagmus treated with tenotomy, 2 were assessed for eye movement. The NAFX scores improved by 8% in 1 child at 1 year and by 36% in the other child at 6 months.
2.3.2 In a case series of 5 patients treated with tenotomy, all patients had a reduced time to target acquisition (measured by infrared reflection or high-speed digital video) 1 year after the procedure (precise reduction not stated).
2.3.3 Two case series of 5 children and 10 adults, reported improvements in best-corrected visual acuity of at least five letters on the Early Treatment Diabetic Retinopathy Study chart (corresponding to a one-line improvement on the Snellen chart) in 4 and 5 patients, respectively (assessed at 6 weeks and 12 months, respectively). The case series of 9 patients reported that 3 patients had an improvement in visual acuity of at least one line, 3 had an improvement of a few letters and 3 had no change (method of assessment and follow-up was not described).
2.3.4 The Specialist Advisers stated efficacy outcomes to include best corrected binocular visual acuity under varying gaze angles, null point width, stereoacuity, ocular movement recordings, nystagmus, visual function in day-to-day life, quality of life, cosmesis and head posture.

 

2.4 Safety
2.4.1 No adverse events were reported in the literature.
2.4.2 The Specialist Advisers considered theoretical adverse events to include damage to the retina or perforation of the globe, infection and misalignment of muscles causing redness, swelling, diplopia, induced strabismus and possible loss of vision. Revision surgery may be needed to correct these adverse outcomes. One Specialist Adviser stated that development of a conjunctival cyst had been reported in the literature.

 

3 Further information
3.1 This guidance requires that clinicians undertaking the procedure make special arrangements for audit. NICE has identified relevant audit criteria and is developing audit support (which is for use at local discretion), which will be available when the guidance is published.

 

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

December, 2008

 

Personal data will not be posted on the NICE website. In accordance with the Data Protection Act names will be anonymised, other than in circumstances where explicit permission has been given.

It is the responsibility of consultees to accurately cite academic work in order that they can be validated.

This page was last updated: 30 March 2010