Web Site Policies and Important Links

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Updating your Browser

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PDF Files

Portable Document Format (PDF) files preserve all the fonts, formatting, graphics, and color of a printed document once it is placed on a website. Several documents on the NEI Website are provided in PDFformat. PDF files require the free Adobe® Reader® software for viewing. If you have a visual impairment, please visit access.adobe.com for help in working more effectively with PDF files.

Copyright Policy

Unless otherwise noted, information on the National Eye Institute (NEI) Website is in the public domain. Public domain information may be freely distributed and copied, but, as a courtesy, it is requested that the National Eye Institute be given an appropriate acknowledgement: “Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).”

When using www.nei.nih.gov, you may encounter documents, illustrations, photographs or other information that has been licensed by private individuals, companies or organizations that may be protected by United States and foreign copyright laws. Transmission or reproduction of these protected items requires the written permission of the copyright owners. For information about the copyright owners of a given graphic, photo or illustration on www.nei.nih.gov how they can be contacted; and what, if any, use those owners allow of their material; please provide the URL and file name to the NEI Website Manager.

Specific Guidelines


Most text appearing on NEI web pages was either prepared by employees of the United States Government as part of their official duties and therefore is not subject to copyright or was prepared under contracts that give NEI the right to place the text into the public domain. The same is true of most publications available for downloading from this website. You may freely copy that material. Please use the following credit: “Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).”

Occasionally, the NEI site may contain documents or links to documents, such as full-text journal articles, that are copyright protected. Web users may view and print these documents but should contact the copyright owner for any other uses.


The NEI Photos and Images catalog is provided as a source of free audiovisuals. Permission is granted to use these items for educational, news media or research purposes, provided the source for each image is credited. The NEI Photos and Images catalog may not be used to promote or endorse commercial products or services. Use by non-profit organizations in connection with fundraising or product sales is considered commercial use.

Permission to use NEI website graphics found any place other than the NEI Photos and Images catalog is granted on a case-by-case basis. Some are public domain, some are created by NEI contractors, some are copyrighted and some are used by NEI with specific permission granted by the owner. Therefore, the logos, photos and illustrations found on the NEI website should not be reused without permission.

For information about the copyright holders of a given photo or illustration on the NEI website; how the owners can be contacted; and what, if any, use those owners allow of their material; please contact the NEI Website Manager and provide the URL, file name, and intended use.

Granting the right to use a graphic from the website does not explicitly or implicitly convey NEI's endorsement of the site where it is used.

Use of NEI logos

The NEI logo should not be used unless a person is given permission by the Chief, Public Liaison and Education Branch for all web-related products. For assistance, please complete this email form.

NEI-funded researchers may use the logo to credit the NEI on their websites.

Contractors may not use the NEI logo on documents that are consulting deliverables or proposals intended for NEI use.

The NEI logo should not be combined with other elements to create a new logo for an office or program.

Schedule for Posting Content

We post information as available, unless otherwise required by law. Some areas of the NEI website are updated daily while others may not be updated for weeks or months.

Information Quality Guidelines

NEI is your trusted source for reliable information. Read more about the NIH information quality guidelines.

Freedom of Information Act

The Freedom of Information Act (FOIA), 5 U.S.C. 552, provides individuals with a right to access to records in the possession of the federal government. The NIH website has information regarding FOIA requests.


Liability: For documents and software available from this server, the U.S. Government does not warrant or assume any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed.

Endorsement: NEI does not endorse or recommend any commercial products, processes or services. The views and opinions of authors expressed on www.nei.nih.gov do not necessarily state or reflect those of the U.S. Government, and they may not be used for advertising or product endorsement purposes.

Pop-Up Advertisements: When visiting www.nei.nih.gov, your Web browser may produce pop-up advertisements. These advertisements were most likely produced by other Web sites you visited or by third party software installed on your computer. NEI does not endorse or recommend products or services for which you may view a pop-up advertisement on your computer screen while visiting our site.

External Links: NEI may provide links on www.nei.nih.gov to other Internet sites for the convenience of Internet users. NEI is not responsible for the availability or content of these external sites, nor does NEI endorse, warrant or guarantee the products, services or information described or offered at these other Internet sites. It is the responsibility of the user to examine the copyright and licensing restrictions of linked pages and to secure all necessary permission. Users cannot assume that the external sites will abide by the same provisions as the NEI Copyright Policy.

Medical Advice: It is not the intention of NEI to provide specific medical advice, but rather to provide users with information to better understand their health and their diagnosed disorders. Specific medical advice will not be provided, and NEI urges you to consult with a qualified physician for diagnosis and for answers to your personal questions.

Web Site Policies and Important Links