Medical Policy: 09.03.01
Original Effective Date: November 1997
Reviewed: January 2017
Revised: January 2016
Benefit determinations are based on the applicable contract language in effect at the time the services were rendered. Exclusions, limitations or exceptions may apply. Benefits may vary based on contract, and individual member benefits must be verified. Wellmark determines medical necessity only if the benefit exists and no contract exclusions are applicable. This medical policy may not apply to FEP. Benefits are determined by the Federal Employee Program.
This Medical Policy document describes the status of medical technology at the time the document was developed. Since that time, new technology may have emerged or new medical literature may have been published. This Medical Policy will be reviewed regularly and be updated as scientific and medical literature becomes available.
Corneal topography describes measurements of the curvature of the cornea. An evaluation of corneal topography is necessary for the accurate diagnosis and follow-up of certain corneal disorders, such as keratoconus, difficult contact lens fits, and pre- and postoperative assessment of the cornea, most commonly after refractive surgery. Various techniques and instruments are available to measure corneal topography:
A number of devices have received clearance for marketing through the U.S. Food and Drug Administration (FDA) 510(k) mechanism. The Orbscan (manufactured by Orbtek and distributed by Bausch and Lomb) received FDA clearance in 1999. The second generation Orbscan II is a hybrid system that uses both projective (slit scanning) and reflective (Placido) methods. The Pentacam (Oculus) is one of a number of rotating Scheimpflug imaging systems produced in Germany.
The American Academy of Ophthalmology (AAO) assessment indicates that computer-assisted corneal topography evolved from the need to measure corneal curvature and topography more comprehensively and accurately than keratometry and that corneal topography is used primarily for refractive surgery.(5) AAO indicates several other potential uses: (1) evaluate and manage patients following penetrating keratoplasty, (2) plan astigmatic surgery, (3) evaluate patients with unexplained visual loss and document visual complications, and (4) fit contact lenses. However, the AAO assessment noted that data are lacking to support the use of objective measurements, as opposed to subjective determinants (subjective refraction) of astigmatism.
Optical coherence tomography (OCT) devices employ non-invasive, non-contact, low-coherence interferometry to obtain high-resolution images and measurements of the anterior segment ocular structures (cornea, anterior chamber, iris and the central portion of the lens).
The devices are designed to image the shape, size and position of anterior components and make precise measurements of the distances between them, including angle-to-angle, angle size in degrees, pupil diameter, anterior chamber depth, and thickness and radii of curvature of the crystalline lens. The anterior segment is measured pre- and postoperatively for laser surgery in refractive surgeries.
Gonioscopy is the gold standard for evaluation of the anterior segment of the eye. Optical coherence tomography (OCT) has also been used to measure the anterior segment of the eye. Several studies have compared OCT and established techniques to measure the anterior segment ocular structure, but none have established the superiority of OCT.
The American Academy of Ophthalmology Preferred Practice Pattern® Summary Benchmarks for primary angle closure, primary open-angle, and primary open-angle suspect recommend gonioscopy as a key element in the workup and management of primary angle and suspect. Optical coherence tomography (OCT) is not mentioned.
An evaluation of corneal topography may be considered medically necessary for the following conditions:
All other uses of corneal topography are considered not medically necessary, including but not limited to:
Note: Non-computerized topography is considered integral to the evaluation and management services. This is included in the payment for these services.
Optical coherence tomography of the anterior eye segment is considered not medically necessary for all indications. Its clinical value has yet to be established.
Wellmark medical policies address the complex issue of technology assessment of new and emerging treatments, devices, drugs, etc. They are developed to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. Wellmark medical policies contain only a partial, general description of plan or program benefits and do not constitute a contract. Wellmark does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Wellmark or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. Our medical policies may be updated and therefore are subject to change without notice.
*Current Procedural Terminology © 2012 American Medical Association. All Rights Reserved.