Clinical and Experimental Optometry

Published on behalf of Optometrists Association Australia, Hong Kong Society of Professional Optometrists and New Zealand Association of Optometrists

Edited by:
H. Barry Collin

Print ISSN: 0816-4622
Online ISSN: 1444-0938
Frequency: Bi-monthly
Current Volume: 93 / 2010
Impact Factor: 1.031

TopAuthor Guidelines

Submit your manuscripts to http://mc.manuscriptcentral.com/ceoptom.

AIMS AND SCOPE
Clinical and Experimental Optometry is the official journal of Optometrists Association Australia, New Zealand Association of Optometrists and Hong Kong Society of Professional Optometrists, and publishes original research papers and reviews in clinical optometry and vision science. Debate and discussion of controversial scientific and clinical issues is encouraged and letters to the Editor and short communications expressing points of view on matters within the Journal's areas of interest are welcome. Clinical and Experimental Optometry also welcomes papers that explore the history of optometry and vision science.

SUBMISSION OF PAPERS
All papers are submitted via Manuscript Central (http://mc.manuscriptcentral.com/ceoptom). New authors need to click CREATE ACCOUNT on the menu bar to obtain a user ID and a password.

ARTICLE CATEGORIES
Clinical and Experimental Optometry publishes the following categories of articles:

Editorials
Most editorials are invited but unsolicited editorials are welcome. Word limit 1500 words but sometimes a longer editorial may be appropriate. No more than 10 references.

Reviews
Word limit up to 10,000 words for a comprehensive review of a broad or complex subject but reviews of narrower scope should be about 5000 words. Reference list can be extensive if one of the intentions of the research underpinning the review is the compilation of a comprehensive bibliography. Otherwise the reference list should be limited to the originating references and the most important and/or most recent subsequent references. An abstract must be provided and should not exceed 300 words.

Original Research Papers
Word limit 5000 words. Apart from reporting formal laboratory or clinical research or the results of surveys, the format of an original research paper can also be used for reporting case studies involving a series of related clinical cases. Reports of single clinical cases should be reported as a CLINICAL COMMUNICATION or a CLINICAL PICTURE. Full details of the format of original research papers are given under Format of Original Research Papers.

Viewpoint
These are articles that make an observation, express a viewpoint or argue a particular interpretation of facts. They can discuss an issue in visual science, optics, diagnosis, treatment, public health or public health policy. Word limit is 2000 words, up to 10 references, 3 illustrations and no abstract. The title should clearly convey the issue and/or the viewpoint expressed so that readers are given a lead as to the content and intent of the article. The title is especially important for PubMed abstracting since without an abstract the potential reader has to rely on the title to decide whether to download the full text.

Guidelines
Clinical and Experimental Optometry publishes guidelines and standards for optometric practice, optometric education, the delivery of eye care services in general or for the management of specific conditions. Usually these are documents prepared and adopted by a peak body such as an optometric association, a government authority or a special interest association that has recognised community standing. Acceptance for publication is subject to editorial assessment of the soundness and appropriateness of the guidelines or standards. Guidelines and standards adopted by a peak body should be authored by the adopting body, although the individual authors of the document can be identified in the text or in acknowledgements. Papers from individuals proposing guidelines or standards that have not been adopted by some peak body should be attributed to individual authors. Guidelines can be submitted in either the category of CLINICAL COMMUNICATION or VIEWPOINT (if the guideline is to do with a broad public health issue) but the published paper will be headed GUIDELINE or STANDARD. The word Guideline or Standard should appear in the title. Statements of guidelines or standards are often very long documents, which the journal is willing to consider publishing in full but every effort should be made to constrain such statements to fewer than 5,000 words.

Clinical Communication
These are articles that make an observation, express a viewpoint or argue a particular interpretation of facts on a matter to do with clinical practice. They can be used to present a case report when that case report illustrates a viewpoint on clinical diagnosis, management or treatment. Word limit is 2000 words, up to 10 references, 3 illustrations and no abstract. The title should clearly convey the issue and/or the viewpoint expressed so that readers are given a lead as to the content and intent of the article. The title is especially important for PubMed abstracting since without an abstract the potential reader has to rely on the title to decide whether to download the full text.

Clinical Picture
This is an alternative way to report a clinical case. Word limit 300-500 words. Up to 5 references. There is no abstract and up to 3 illustrations, which may be clinical photographs or other forms of clinical imaging including angiograms, corneal topographic maps, OCT, visual field charts and so forth. They can report a rare condition, an unusual presentation or fairly ordinary cases that demonstrate a clinical lesson, such as a risk of misdiagnosis or the effectiveness of treatments. Clinical pictures need not be of ocular disease but can be about refractive errors, optical dispensing, contact lenses and ocular motility disorders or any other aspect of optometry. The title should convey the key message of the clinical case.

Letters
No more than 500 words and 5 references. Special guidance about writing letters is given at the end of these author instructions.

Profile, Obituary or Historical Overview
Most will be less than 2000 words but may be up to 4000 words for well researched historical observations or for profiles and obituaries of an especially prominent person or that document a historical context. No abstract. The title for profiles and obituaries should include a phrase that conveys the special attributes of the person. Likewise the title for historical overviews should clearly indicate the scope and intent of the article.

Word limits are for the text body not including any abstract, tables, figure captions or references.

Clinical and Experimental Optometry encourages authors to include illustrations with all papers as illustrated articles are more often read than those without illustrations. Clinical and Experimental Optometry will publish illustrations in colour without author charges when colour is necessary.
Further guidance on the requirements for each type of article is set out below.

EDITORIAL REVIEW AND ACCEPTANCE
The primary criterion for selection of a paper for publication in Clinical and Experimental Optometry is that it adds to knowledge and/or understanding. The merit of papers submitted to Clinical and Experimental Optometry is determined by anonymous peer review. Papers are evaluated by the Editor, an Associate Editor and two reviewers against the following criteria: originality of the work, importance and contemporary relevance, validity, experimental design, contribution to knowledge in the field, soundness of conclusions, clarity and organisation of the paper. Final acceptance or rejection rests with the Editor, who reserves the right to refuse any material for publication. The Journal aims to provide refereed comments within eight weeks from the date of receipt of a manuscript. The Journal offers rapid publication for well-written and well-presented papers. Subject to prompt return of a revised manuscript, publication within six months is possible.

ORIGINALITY
All papers must present original ideas, viewpoints or data that have not been published by or submitted to another journal.

Secondary publication, that is publication of material that has been or will be published in another journal or book is only acceptable in limited circumstances, namely (a) the paper is an expanded version of a paper, abstract or poster published as conference proceedings (b) the prior publication was in a language other than English and the paper is of sufficient importance to warrant its publication in English so as to reach a wider audience and (c) a paper of high importance or interest to more than one discipline that has been published in a journal reaching one of those disciplines and has been re-written to place it in context for the ophthalmic disciplines. Secondary publications must cite the primary publication and explain the relationship between the two.

OVERLAPPING PUBLICATION
Papers that draw on the same database as that used in another paper that has or will be published in this or another journal must cite the other publication and clearly describe the relationship between the two.

PRIVACY AND CONFIDENTALIALITY
Manuscripts are considered privileged documents owned by the authors. The names of authors are known to editors and reviewers but they will not disclose any information about the manuscript or their assessment of it to third parties. The names of reviewers are not disclosed to authors.

AUTHORSHIP
All authors must have made a substantial contribution to (1) conception and design, acquisition of data or analysis and interpretation of data and (2) drafting the article or revising it critically for important intellectual content; and (3) final approval of the version to be published. Funding, data collection or general supervision alone do not justify authorship. All who qualify for authorship should be listed as authors. Deciding authorship and its order must be a joint decision of the authors and must be justifiable. Papers from a large multi-centre group may be attributed to the group (as 'author') but must identify the individual authors who meet the criteria above; others in the group may be acknowledged in "acknowledgements". Authors are required to sign a declaration of authorship before their paper can be published.

ACKNOWLEDGMENTS
All contributors who do not meet the criteria for authorship should be listed in an acknowledgments section at the end of the main text of the paper. Examples of those who might be acknowledged include those who provided purely technical help, those who collected data, provided writing assistance, or a colleague who provided only general support. Every person who is acknowledged must provide written permission to the corresponding author before being acknowledged. This is to avoid associating persons with a paper and its conclusions when they may not wish to be so associated.

FUNDING SOURCES
Funding from sources external to the author's institutions must be disclosed, first as a courtesy to the funding agency but more importantly so that readers can judge whether there is any potential for bias. Funding agencies should be listed after acknowledgments.

CONFLICT OF INTEREST
Authors must disclose in the manuscript any association they may have with a commercial organisation or any financial interest in a product described or reported on in the manuscript that may give rise to the perception of a potential conflict of interest.

ETHICAL CONSIDERATIONS.
(1) Ethics approval
Projects involving the participation of human subjects or the use of experimental animals must have been approved by an institutional ethics committee and this must be reported in the manuscript.

(2) Ethical standards
The care and use of animals must have been in accordance with institutional and national guidelines and in accordance with legal requirements in the author's country and for human subjects, the investigation must have been conducted in accordance with the Declaration of Helsinki of 1975 (As revised in Tokyo in 2004) and this must be stated in the manuscript.

(3) Anonymity of subjects and patients
Any identifying names or initials on photographs or visual field charts must be removed or obscured and nothing in the text should enable the subject or patient to be identified. Written consent must be obtained if a photograph of the face or any part of the face of the patient is in any photograph. Authors must certify in writing that they hold written patient consent to publish if the patient is in any way able to be identified through the photograph or where the unique nature of the incident reported makes it possible for the patient to be identified. The Editor may ask for a copy of the written consent.

(4) Informed consent
Informed consent must have been obtained from all adult subjects participating in an investigation and from parents or legal guardians of participating minors and this must be stated in the manuscript.

SUBMISSION OF MANUSCRIPTS
Manuscripts should be submitted online at Manuscript Central. Authors must supply an email address as all correspondence will be by email. Two files should be supplied: the covering letter and the manuscript.

Covering letter
The covering letter can be typed or pasted into the cover letter window or uploaded as a Word file. It can provide any information that the corresponding author considers will assist the editor and must include:

(1) Statement of authorship responsibility to the effect 'I certify on behalf of myself and all co-authors that we have all participated sufficiently in the conception and design of this work and the interpretation of the data (when applicable), as well as in the writing of the manuscript, to take public responsibility for it. Neither this manuscript nor one with substantially similar content under our authorship has been published or is being considered for publication elsewhere, except (describe exceptions).'

(2) Statement of financial disclosure and conflict of interest. 'I certify that any affiliations with or involvement in any organisation or entity with a direct financial interest in the subject matter or materials discussed in the manuscript (for example, employment, consultancies, stock ownership, honoraria, expert testimony) are disclosed in the paper.'

(3) Permissions. If tables or figures have been reproduced from another source the cover letter should advise that permission to reproduce them has been obtained from the copyright holder (usually the Publisher - in which case upload a copy of the permission) or is being obtained.

Manuscript
The manuscript should be in Word (.doc), preferably using Times font. Use 'English Equation Editor' for equations in the document.
Upload the manuscript only onto Manuscript Central as a single document. This document should include: a title page with the authors' names in full, their qualifications and affiliations; an abstract on a separate page (when an abstract is required), text, references, tables and the figure captions (each figure is to be uploaded as a separate file). Tables can be in the text or on separate pages. Figure captions should be on a separate page after references.
If you have inserted references using 'Insert footnote', remove the electronic links before submission so that the list of references is plain text.
Do NOT include figures in the manuscript. Indicate in the text where figures should be located with the words 'Insert Figure X here'.

Figures
Load each figure as a separate document in TIF or EPS format (but without a thumbnail preview). Original photographs can be submitted as JPEG files but TIF or EPS format is preferred.
Photographs and scanned illustrations must have a minimum resolution of 300 dpi in a width of at least 12 cm. Excel files of graphs can be uploaded but only one sheet at a time. Colour photographs and other colour illustrations will be published in colour only when colour is necessary. Do not submit diagrams and graphs in colour unless colour is needed. Click 'Get Help Now' in Manuscript Central for more information about other acceptable file formats.

PREPARATION OF MANUSCRIPTS
• Submissions should be double-spaced.
• All margins should be at least 30 mm.
• All pages should be numbered consecutively in the top right-hand corner, beginning with the title page.
• Do not use Enter at the end of lines within a paragraph. Turn the hyphenation option off; include only those hyphens that are essential to the meaning.
• Specify in words any special characters used to represent non-keyboard characters.
• Take care not to use l (ell) for 1 (one), O (capital o) for 0 (zero) or ß (German esszett) for Greek beta.
• Use a tab, not spaces, to separate data points in tables. If you use a table editor function, ensure that each data point is contained within a unique cell (that is, do not use Enter within cells).

Word 2007
Will authors please note that Word 2007 is not yet compatible with journal production systems. Unfortunately, the journal cannot accept Microsoft Word 2007 documents until such time as a stable production version is released. Please use Word's 'Save As' option therefore to save your document as an older (.doc) file type.

STYLE OF THE MANUSCRIPT
Manuscripts should be written so that they are intelligible to the professional reader who is not a specialist in the particular field. They should be written in a clear, concise, direct style. Where contributions are judged as acceptable for publication on the basis of content, the Editor and the Publisher reserve the right to modify typescripts to ensure conformity to the Journal's style or to eliminate ambiguity and repetition and improve clarity. Authors are responsible for all statements made in their work, including changes made by the Editor and the Publisher that have been authorised by the corresponding author (by proof approval).

Manuscripts should follow the style of the Vancouver agreement detailed in the International Committee of Medical Journal Editors' revised 'Uniform Requirements for Manuscripts Submitted to Biomedical Journals: Writing and Editing for Biomedical Publication'.

Spelling
The Journal uses UK spelling and authors should therefore follow the latest edition of the Concise Oxford Dictionary.

Units
All measurements must be given in SI or SI-derived units.

Abbreviations
Abbreviations should be used sparingly - only where they ease the reader's task by reducing repetition of long, technical terms. Initially use the word in full, followed by the abbreviation in parentheses. Thereafter use the abbreviation only.

Trade names
Chemical substances should be referred to by the generic name only. Trade names should not be used. If proprietary drugs have been used in the study, refer to these by their generic name, mentioning the proprietary name, and the name and location of the manufacturer, in parentheses. Commercially available equipment should be identified by the type of instrument, its maker and the model number.

FORMAT OF ORIGINAL RESEARCH PAPERS
See below for additional guidance for other categories of articles.

The length of an original research article (excluding references, tables and appendices) should not exceed 5000 words. Manuscripts should be presented in the following order: (i) title page, (ii) abstract and key words, (iii) text, (iv) acknowledgements, (v) statement on sources of funding (vi) statement of conflict of interest (vii) references, (viii) appendices, (ix) figure legends, (x) tables, each complete with title and footnotes and (xi) figure captions. Each figure should be uploaded as a separate file. Explanatory footnotes should be used sparingly and only when necessary.

Title page
The title page should contain (i) the title of the paper, (ii) the preferred given name and family name of all authors with their qualifications and (iii) the addresses of the institutions at which the work was carried out together with (iv) the full postal and email address, plus facsimile and telephone numbers, of the author to whom correspondence about the manuscript should be sent. The present address of any author, if different from that where the work was carried out, should be supplied in a footnote. Titles should be informative and contain the major key words, however, they should not include abbreviations. The title of research papers should be no longer than 15 words. A short running title (less than 40 characters) should also be provided for all papers.

Abstract and key words
All articles must have a structured abstract that states in 300 words or fewer the purpose, basic procedures, main findings and principal conclusions of the study. Divide the abstract with the headings: Background, Methods, Results, Conclusion. Review articles should have an unstructured abstract. The abstract should not contain abbreviations or references. Five key words, for the purposes of indexing, should be supplied below the abstract, in alphabetical order, and should be taken from those recommended by the US National Library of Medicine's Medical Subject Headings (MeSH) browser list.

Text
Authors should use the following subheadings to divide the sections of their manuscript: Introduction, Methods, Results and Discussion.

Introduction
State the purpose of the article and summarise the rationale for the study or observation. Give only strictly pertinent references and do not include data or conclusions from the work being reported.

Methods
Provide a clear description of the methods, succinct yet sufficiently detailed to enable replication of the experiment.

Results
Results should be presented in tables and figures as far as possible. The text should not duplicate results shown in tables and figures but simply draw attention to the key features of the results and the key outcomes of statistical analysis.

Discussion
Emphasise the new and important aspects of the study and the conclusions that follow from them. Do not repeat in detail data or other material given in the introduction or results. Include the implications of the findings and their limitations. Relate the observations to other relevant studies. A conclusions section can be added after the discussion if the discussion section is long and there are multiple conclusions.

References
All statements of fact or allusions to past work and views must be supported by appropriate references to published work or other sources so readers can verify for themselves the veracity of statements that draw on the work or thinking of others. The exception can be when the facts have been long known and are well accepted.

Authors should avoid excessive referencing. When many sources can be used to support a statement of fact, a generalisation or a viewpoint, a selection of suitable references should be made rather than citing them all. Criteria for selection of the most suitable references to use might be: the references that first made the observation, the references that have the best supporting evidence or have been published in a journal known for its rigorous editorial standards and, apart from the originating reference(s), the most recent references.

An exception to this requirement to be sparing in the number of references cited is a review in which the authors have compiled an exhaustive bibliography on the topic to assist other researchers in the field.

Authors are responsible for the accuracy of the references they cite. The Editors and reviewers will be alert to the possibility of inaccurately cited references and will spot check references and will reject papers in which there are serious errors in references, either in the citation of references that do not support the views expressed by the authors or errors in the bibliographic details.

Style of reference citation
The Vancouver system of referencing should be used (examples are given below). In the text, references should be cited using superscript Arabic numerals in the order in which they appear in the text. If cited in tables or figure legends, number according to the first identification of the table or figure in the text. In the reference list, cite the names of all authors. Do not use ibid. or op cit. Reference to unpublished data and personal communications should not appear in the list but should be cited in the text only (for example, Smith A, 2000, unpublished data). All citations mentioned in the text, tables or figures must be listed in the reference list. Names of journals should be abbreviated in the style used in Index Medicus. Authors are responsible for the accuracy of the references.

Journal article
1. Vega KJ, Pina I, Krevsky B. Heart transplantation is associated with an increased risk for pancreatobiliary disease. Ann Intern Med 1996; 124: 980-983.

Book
2. Ringsven MK, Bond D. Gerontology and Leadership Skills for Nurses, 2nd ed. Albany, NY: Delmar Publishers, 1996.

Chapter in a book
3. Phillips SJ, Whisnant JP. Hypertension and stroke. In: Laragh JH, Brenner BM, eds. Hypertension: Pathophysiology, Diagnosis, and Management, 2nd ed. New York: Raven Press, 1995. p 465-475.

Journal article on the Internet
4. Abood S. Quality improvement initiative in nursing homes: the ANA acts in an advisory role. Am J Nurs [serial on the Internet]. 2002 Jun [cited 2002 Aug 12];102(6):[about 3 p.]. Available from: http://www.nursingworld.org/AJN/2002/june/Wawatch.htm

Monograph on the Internet
5. Foley KM, Gelband H. Improving palliative care for cancer [monograph on the Internet]. Washington: National Academy Press; 2001 [cited 2002 Jul 9]. Available from: http://www.nap.edu/books/0309074029/html/.

Conference proceedings
6. Harnden P, Joffe JK, Jones WG. Germ cell tumours V. Proceedings of the 5th Germ Cell Tumour Conference; 2001 Sep 13-15; Leeds, UK. New York: Springer; 2002.

We recommend the use of a tool such as EndNote or Reference Manager for reference management and formatting. EndNote reference styles can be searched for at: http://www.endnote.com/support/enstyles.asp. Reference Manager reference styles can be searched for at: http://www.refman.com/support/rmstyles.asp

Tables
Tables should be self-contained and complement, but not duplicate, information contained in the text. Number tables consecutively in the text in Arabic numerals. Present tables on a separate page with the legend above. Legends should be concise but comprehensive - the table, legend and footnotes must be understandable without reference to the text. Vertical lines should not be used to separate columns. Column headings should be brief, with units of measurement in parentheses; all abbreviations must be defined in footnotes. Footnote symbols: †, ‡, §, ¶, should be used (in that order) and *, **, *** should be reserved for p-values. Statistical measures such as SD or SEM should be identified in the headings.

Figures
All illustrations (photographs, line drawings and graphs) are classified as figures. Figures are numbered using Arabic numerals in the order in which they are cited in the text. Line drawings and graphs should be sized so they can be reduced in size to fit in 1 column (58 mm), a half-page (85 mm), 2 columns (122 mm) or across the page (185 mm). Simple graphs and drawings should be sized to fit in 1 column. Two or three related figures should be drawn so they can be grouped to fit across 2 columns or the full width of the page. Line figures should be black and white. Do not use three-dimensional bars and columns in graphs. Use only white, black and greyscale fill. Do not use patterned fills. Colour should be used only when the illustration is very complex and colour is necessary for interpretation. Clinical and Experimental Optometry cannot guarantee that colour will be used in line drawings and graphs. Use Helvetica typeface for legends and numbers. Do not use bold face. Type size should be 9 point when reduced: if the original figure is to be reduced to half size when printed, use 18 or 20 point type in the original. Use horizontal and vertical grid lines sparingly. If the graph is simple, do not use any grid lines. In more complex graphs where the reader may wish to read off values, use a minimum number of horizontal grid lines. In line graphs use these symbols in this order: unfilled and filled circles, unfilled and filled squares, and unfilled and filled triangles.

COPYRIGHT - EXCLUSIVE LICENCE FORM
The corresponding authors will be asked to sign an exclusive licence form on behalf of all authors. In signing the form it is assumed that authors have obtained permission to use any copyrighted or previously published material. Articles cannot be published until a signed form has been received.

PROOFS
It is essential that corresponding authors supply an email address to which correspondence can be emailed while their article is in production. Notification of the URL from where to download a Portable Document Format (PDF) typeset page proof, associated forms and further instructions will be sent by email to the corresponding author. The purpose of the PDF proof is a final check of the layout and editorial changes, and of tables and figures. Alterations other than the essential correction of errors are unacceptable at PDF proof stage. The proof should be checked, and approval to publish the article should be emailed to the Publisher by the date indicated, otherwise, it may be signed off by the Editor or held over to the next issue.

OFFPRINTS
A free PDF offprint will be supplied to the corresponding author. A minimum of 50 paper offprints will be provided on request, at the author's expense. These paper offprints may be ordered online. Please visit http://offprint.cosprinters.com, fill in the necessary details and ensure that you type information in all of the required fields. If you have queries about offprints please email offprint@cosprinters.com.

EARLY VIEW
Clinical and Experimental Optometry is covered by Wiley-Blackwell's Early View service. Early View articles are complete full-text articles published online in advance of their publication in a printed issue. Therefore, articles are made available as soon as they are ready, rather than being held for the next scheduled print issue. Early View articles are complete and final. They have been fully reviewed, revised and edited for publication, and the authors' final corrections have been incorporated. Because they are in final form, no changes can be made after online publication. The nature of Early View articles means that they do not yet have volume, issue or page numbers, so Early View articles cannot be cited in the traditional way. They are therefore given a Digital Object Identifier (DOI), which allows the article to be cited and tracked before it is allocated to an issue. After print publication, the DOI remains valid and can continue to be used to cite and access the article. More information about DOIs can be found at http://www.doi.org/faq.html.

WILEY-BLACKWELL JOURNALS ONLINE
Visit the Clinical and Experimental Optometry home page for more information, and Wiley-Blackwell's web pages for submission guidelines and digital graphics standards. Clinical and Experimental Optometry is also available online at http://www3.interscience.wiley.com

Wiley-Blackwell Author Services
Author Services enables authors to track their article, once it has been accepted, through the production process to publication online and in print. Authors can check the status of their articles online and choose to receive automated emails at key stages of production so they do not need to contact the production editor to check on progress. Visit http://authorservices.wiley.com/bauthor for more details on online production tracking and for a wealth of resources, including FAQs and tips on article preparation, submission and more.

EDITORIAL OFFICE ADDRESS
Editor, Clinical and Experimental Optometry, 204 Drummond Street, Carlton (PO Box 185, Carlton South) Victoria 3053, Australia. Email: cxo.editor@optometrists.asn.au; tel: 61 3 9663 6833; fax: 61 3 9663 7478.

LETTERS
Readers of Clinical and Experimental Optometry are encouraged to write to the Editor on matters arising from articles published in the Journal. Letters provide an opportunity for an open and dynamic exchange of views. Letters can provide information supportive of the conclusions reached in articles or can provide comment that calls into question facts or conclusions.

Guidelines for letter writers
• Always address specific points in the article on which you are commenting.
• Be courteous. Letters can be forceful, even emotional, but should never attack the character of the author.
• Support your arguments with verifiable facts and references (letters should have no more than five references).
• Keep it brief - no more than 500 words. If you want to write at greater length, submit a viewpoint or offer to write a guest editorial.
• Be timely - submit your letter within five weeks of publication of the article on which you are commenting. The Editor will endeavour to publish letters in the issue immediately after that in which the article commented on was published.
• Clearly state any interest you have that might be considered to give rise to a conflict of interest. You may write a letter and have it published even if your viewpoint is influenced by a particular interest, but you must tell readers about it.
• Identify yourself (anonymous letters will not be published) and give your affiliations.

How are letters processed?
Letters are reviewed by the Editor who may seek advice from experts. He will send your letter to the senior author of the article on which you offer comment and invite a response. When possible, your letter and the response will be published in the same issue. The Editor will not publish your letter if he believes the comments are not well founded or do not contribute usefully to scientific or professional debate. He may edit your letter but he will not alter the nature of the comments you make. He may telephone you to discuss points that are unclear or which he considers should or should not be made. Letters to the Editor should be sent through Manuscript Central.