Interventional procedure consultation document

Laser correction of refractive error following non-refractive ophthalmic surgery

Laser surgery to correct refractive errors caused by eye surgery

Refractive errors include common conditions such as myopia (short sightedness) and hyperopia (long sightedness) that impede the accuracy of vision without spectacles or contact lenses.

Laser surgery aims to establish visual accuracy by changing the shape of the cornea (the clear outer layer at the front of the eye), so that light rays are more precisely directed onto the retina.

The National Institute for Health and Clinical Excellence (NICE) is examining laser correction of refractive error following non-refractive ophthalmic surgery 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 laser correction of refractive error following non-refractive ophthalmic 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 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• The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.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: 21 December 2010

Target date for publication of guidance: March 2011

1   Provisional recommendations

1.1  Current evidence on the safety and efficacy of laser correction of refractive error following non-refractive ophthalmic surgery is adequate to support the use of this procedure provided that normal arrangements are in place for clinical governance, consent and audit.

1.2  Patient selection and treatment should only be carried out by ophthalmologists who specialise in corneal surgery.

2   The procedure

2.1  Indications and current treatments

2.1.1  Refractive errors can occur as a result of non-refractive ophthalmic surgery such as cataract surgery or corneal transplantation. Patients with these refractive errors may have myopia, hyperopia or astigmatism. 

2.1.2  The refractive errors are usually managed by wearing spectacles or contact lenses. Laser correction may be offered to patients who are intolerant of, or who would prefer not to wear, spectacles or contact lenses.

2.2   Outline of the procedure

2.2.1  Three types of laser correction are considered in this guidance: these are photorefractive keratectomy (PRK), laser epithelial keratomileusis (LASEK) and laser in situ keratomileusis (LASIK). All are performed with the patient under local anaesthesia. If required, the procedure can be performed on both eyes during the same surgical session

2.2.2  PRK involves removal of the corneal epithelium by surgical dissection followed by excimer laser ablation of a calculated amount of the stromal bed of the cornea. LASEK is a modification of PRK in which dilute alcohol is used to loosen the corneal epithelium before it is lifted from the treatment zone as a hinged sheet, and then replaced at the end of the procedure. In LASIK, a flap is created with a microkeratome, lifted before laser ablation and then repositioned. Patients may be given pre- or post-operative antibiotics as prophylaxis against infection.

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/guidance/IP/789/overview

2.3   Efficacy

2.3.1  A case series of 62 patients (87 eyes) who had LASIK after non-refractive ophthalmic surgery or refractive surgery reported that mean spherical equivalent refraction (MSER; a negative reading indicates myopia, a positive reading indicates hyperopia) improved from −5.25 D preoperatively to −0.70 D at 1-year follow-up.

2.3.2  A case series of 59 patients (85 eyes) who had LASIK after multifocal intraocular lens implantation reported that MSER improved from −0.34 D preoperatively to −0.07 D at 6-month follow-up (p = 0.004).

2.3.3  A case series of 48 patients (57 eyes) who had LASIK after penetrating keratoplasty (PK) reported that MSER improved from −3.94 D preoperatively to −0.61 D at 2-year follow-up.

2.3.4  A case series of 38 patients (46 eyes) who had LASIK after PK reported improvement in preoperative mean spherical refraction in myopic eyes (n = 40) and hyperopic eyes (n = 3) of −5.16 D to −0.44 D and 5.75 D to 1.67 D respectively, and improvement in mean preoperative cylindrical refraction in eyes with mixed astigmatism (n = 3) of −5.50 D to −2.42 D at 5-year follow-up. Overall, at 5-year follow-up, 63% (29/46) had a refractive error within 1.00 D of emmetropia.

2.3.5  The case series of 62 patients (87 eyes) reported that the proportion of patients with uncorrected visual acuity of 0.5 or better increased from 5% (4/87) preoperatively to 70% (61/87) at 1-year follow-up.

2.3.6  The case series of 59 patients (85 eyes) reported uncorrected distance visual acuity of 20/25 or better in 92% of eyes at 6-month follow-up. The case series of 48 patients (57 eyes) reported that the proportion of patients with uncorrected visual acuity of 20/40 or better increased from 0% preoperatively to 43% (12/28) at 2-year follow-up.

2.3.7  Case series of 62, 59 and 48 patients who had LASIK after non-refractive ophthalmic surgery reported LASIK re-operation in 22% (19/87), 6% (5/85) and 9% (5/57) of eyes because of residual refractive errors, at follow-up of 12, 6 and 24 months respectively.

2.3.8  The Specialist Advisers listed key efficacy outcomes as uncorrected visual acuity, reduced refractive error, maintained best‑corrected spectacle vision and improved quality of life.

2.4   Safety

2.4.1  The case series of 48 patients (57 eyes) reported that 15% (8/52) of eyes lost two or more Snellen lines of best-corrected visual acuity at 1-year.

2.4.2  A case series of 41 patients who had PRK after PK reported 3 eyes with grade 2 haze (1 eye in the regular astigmatism group and 1 eye in the irregular astigmatism group at 8 months, and 1 eye in the irregular astigmatism group at 10 months). All eyes required re-treatment.

2.4.3  The case series of 59 patients (85 eyes) reported 4 eyes with moderate or marked dry eye which developed between 3 and 6 months follow-up. All eyes were treated with frequent lubricant. The case series of 48 patients (57 eyes) treated with LASIK after PK reported persistent dry eye in 3 eyes at a mean follow-up of 21.4 months.

2.4.4  The case series of 48 patients reported: 4 eyes with epithelial ingrowth requiring removal between 1 week and 12 months, 2 eyes that required repeat graft for persistent astigmatism between 1 and 3 years, 3 eyes needing repeat graft for oedema between 8 months and 3 years, and 5 eyes with flap dislocation between 1 day and 1 week (2 required sutures, 1 flap was removed, 1 was repositioned without sutures and 1 was not described).

2.4.5  A case series of 57 eyes reported: 2% (1/57) of eyes with macular haemorrhages 7 days after LASIK, 7% (4/57) of eyes with epithelial ingrowth, 4% (2/57) of eyes with induced astigmatism, 4% (2/57) of eyes with free cap and 25% (14/57) of eyes with night vision problems at a mean follow-up of 9 months.

2.4.6  The case series of 38 patients (46 eyes) who had LASIK after PK reported endothelial rejection which was successfully treated in 1 eye.

2.4.7  The Specialist Advisers considered theoretical adverse events to include ectasia, recurrent epithelial erosion syndrome, epithelial defects, bleeding from flap edge, interface haemorrhage, interface debris, flap striae, diffuse lamellar keratitis, corneal scarring, glare, infection and pain after treatment.

3   Further information

3.1  For related NICE guidance see www.nice.org.uk

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

November 2010

_{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.}