Interventional procedure consultation document

Phototherapeutic laser keratectomy for corneal surface irregularities

Eye disorders in which the outer clear layer of the eye (the cornea) becomes scarred, uneven, less flexible, or develops recurrent ulcers may result in loss of ability to focus sharply.

Phototherapeutic keratectomy uses a laser to remove layers of the cornea in order to produce a smooth even surface with the aim of improving vision.

The National Institute for Health and Clinical Excellence (NICE) is examining phototherapeutic laser keratectomy for corneal surface irregularities 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 phototherapeutic laser keratectomy for corneal surface irregularities.

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• The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.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: 16 June 2010

Target date for publication of guidance: September 2010

1  Provisional recommendations

1.1  Current evidence on the safety and efficacy of phototherapeutic laser keratectomy for corneal surface irregularities 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 be carried out only by ophthalmologists who specialise in corneal surgery.

2  The procedure

2.1  Indications and current treatments

2.1.1  Symptomatic corneal surface irregularities may result from a range of pathologies including band keratopathy, corneal scarring, nodular degeneration, epithelial basement membrane dystrophy or other dystrophies. Symptoms may include loss of visual acuity, pain, sensitivity to light and foreign body sensation.

2.1.2  Treatment aims to restore a normal regular corneal surface and adherence between the epithelium and Bowman’s membrane (a basement membrane that lies between the outer layer of stratified epithelium and the substance of the cornea) with associated improvement in visual acuity and comfort.

2.1.3  Standard treatment includes lubrication of the ocular surface, bandage contact lens placement or topical medication. Surgical procedures may include anterior stromal puncture, mechanical debridement, lamellar keratoplasty or resurfacing keratectomy using a diamond burr. Corneal transplantation may be considered in eyes refractory to treatment.

2.2  Outline of the procedure

2.2.1  The aim of phototherapeutic laser keratectomy for corneal surface irregularities is to create a smooth stromal surface to improve postoperative corneal clarity, decrease existing scarring and facilitate subsequent epithelial adhesion.

2.2.2  Local anaesthetic eye drops are applied and the corneal epithelium is mechanically removed. A laser is used to sequentially ablate uniformly thin layers of corneal tissue, to create a smooth surface which then becomes re-epithelialised. Postoperative management consists of an eye pad, topical antibiotics, sedatives and non-steroidal anti-inflammatory drugs.

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/IP788overview

2.3  Efficacy

2.3.1  A non-randomised controlled study of 39 patients reported no significant difference in overall change in best corrected visual acuity (BCVA) between patients treated by laser phototherapeutic keratectomy and those treated by diamond burr polishing at 7-month follow-up (p = 0.6): BCVA improved in 36% (5/14) and 14% (3/21) of eyes, remained unchanged in 64% (9/14) and 81% (17/21) of eyes and worsened in 0% (0/14) and 5% (1/21) of eyes respectively.

2.3.2  In a case series of 211 patients (232 eyes) mean BCVA improved by 1.4 lines from baseline at 2-year follow-up (p < 0.002). No significant difference was reported in BCVA improvement between subgroups of patients with corneal dystrophy, nodular degeneration, corneal scar, or band keratopathy (absolute figures not stated) (p = 0.15).

2.3.3  A case series of 216 patients (252 eyes) reported that among eyes with recurrent erosion at baseline, further recurrent erosion was reported in 9% (9/103) of eyes at 12-month follow-up.

2.3.4  The case series of 216 patients reported that 100% (29/29) of eyes with bandlike keratopathy were pain free by 6-day follow-up.

2.3.5  A case series of 191 patients (203 eyes) reported that significantly fewer patients with bullous keratopathy had severe pain, photosensitivity and/or watering symptoms at 6-month follow-up (n = 15) compared to baseline (n = 56) (p < 0.017). Similarly, significantly fewer patients with corneal scaring had severe symptoms at 6-month follow-up (n = 4) compared to baseline (n = 13) (p < 0.0001).

2.3.6  The Specialist Advisers listed key efficacy outcomes as visual acuity, ocular surface health, ocular comfort and pain relief.

2.4  Safety

2.4.1  Recurrent keratitis requiring penetrating keratoplasty was reported in 1% (3/232) of eyes at up to 2-year follow-up in the case series of 211 patients.

2.4.2  Progressing keratolysis at 8-day follow-up, circular subepithelial corneal scarring at 5-month follow-up (both requiring penetrating keratoplasty), progressive kerectasia at 6 months (sequelae not reported), and sterile corneal immune rings at 4-day follow-up occurred in 1 case report each.

2.4.3  A loss of BCVA of 2 lines or more was reported in 13% (3/24) of patients at 2-year follow-up in the case series of 211 patients.

2.4.4  Idiopathic iritis and a marginal corneal ulcer developed in 1 eye each at up to 2-year follow-up in the case series of 211 patients.

2.4.5  Mild postoperative haze was reported in 11% (22/203) of eyes in the case series of 191 patients; this resolved in 12 patients by 6-month follow-up. There was no significant difference in the occurrence of mild haze between patients treated by laser phototherapeutic keratectomy (33% [5/15]) or by diamond burr polishing (26% [7/27]) in the non-randomised controlled study of 39 patients at 7-month follow-up (p = 0.38).

2.4.6  The Specialist Advisers identified corneal infection as an adverse event reported in the literature. They considered theoretical adverse events to include epithelial defect, corneal ectasia, scarring and induction of astigmatism or refractive error.

2.5  Other comments

2.5.1  The Committee noted that the published evidence comprised a mixture of different indications and outcomes, but nevertheless they considered that the case for safety and efficacy was adequately supported by this evidence and by specialist advice. 

2.5.2  NICE received 3 completed questionnaires from patients treated by the procedure. They reported improvements in quality of life including reduced photosensitivity (which had required sunglasses), and the ability to walk with more confidence.

3  Further information

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

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee
April 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.}