Coding for AMD Diagnostics

Codes for the new preferential hyperacuity perimetry test.
New technology continues to offer opportunities for ophthalmologists. One exciting area is early detection of exudative (wet) AMD. A new test, preferential hyperacuity perimetry (PHP), is particularly helpful in light of new treatments for this visually debilitating disease.

Q. What is PHP?
PHP is a rapid, specialized perimetry based on the well-studied visual phenomenon of hyperacuity. Hyperacuity (also called Vernier acuity) is the ability to identify a subtle misalignment of one object compared with another. PHP allows distortions or scotomata to be mapped by flashing a dot deviation signal across different areas of the macula.
PHP is intended for use in the detection and characterization of central and paracentral metamorphopsia in patients with AMD. It is also useful as an aid in monitoring progression of disease factors causing metamorphopsia including, but not limited to, choroidal neovascularization (CNV).
A recent study1 showed that PHP testing yielded high percentages (more than 80%) of sensitivity in detecting new CNV in patients presenting with intermediate-through-advanced AMD. This is an improvement over previous methods of early diagnosis, which supports the researchers� conclusion that PHP should be considered a useful adjunct to the manage- ment of the intermediate stage
of AMD.

Q. What code should be used to describe PHP?
Visual field testing, or perimetry, is described by three different CPT codes: 92081 (limited), 92082 (intermediate) and 92083 (extended). While the examples given in CPT do not mention PHP, a good choice to describe PHP is 92081, visual field examination, unilateral or bilateral, with interpretation and report; limited examination.
An exception to this coding advice is made for TrailBlazer Medicare; they instruct providers to use 92499 (unlisted ophthalmological service) to identify PHP on claims. TrailBlazer specifically does not cover PHP, so an ABN is required prior to any testing.

Q. Does Medicare have a national policy for perimetry?
The National Coverage Determination (NCD �80.9) states �Computer enhanced perimetry involves the use of a micro-computer to measure visual sensitivity at preselected locations in the visual field. It is a covered service when used in assessing visual fields in patients with glaucoma or other neuropathologic defects.� The NCD does not mention AMD as an indication for perimetry, so you should refer to local coverage determination (LCD) policies for additional instruction. The NCD does not supersede a local policy. Several Medicare carriers include AMD as a covered indication in their coverage policies for perimetry.

Q. What about repeat testing?
Since lesions can grow rapidly, leading experts in the field recommend repeat testing with PHP every three months for early detection of conversion from dry AMD to wet AMD. Coverage for repeat testing will depend on your Medicare carrier�s LCD. Many carriers do not stipulate a specific limitation, while others do. Some consider visual field testing medically necessary for the initial evaluation of macular degeneration related to central vision loss, but repeated testing for AMD or an experienced central vision loss are not considered necessary unless changes in vision are documented or to evaluate the results of a surgical intervention. Other carriers have a more generous policy (see author�s note)..
In the absence of a clear coverage policy, an Advance Beneficiary Notice (ABN) is strongly advised. Explain to the patient why the test is necessary and that Medicare will likely deny the claim. Ask the patient to assume financial responsibility for the charge; get an ABN signed and submit your claim with modifier -GA. You may collect your fee from the patient at the time of service or wait for a Medicare denial. If both the patient and Medicare pay, promptly refund the patient or show why Medicare paid in error. OM

Reference
1. Alster Y, Bressler NM, Bressler SB, et al. Preferential Hyperacuity Perimeter (Preview PHP) for Detecting Choroidal Neovascularization Study. Ophthalmology. 2005;112:1758-1765.

Author�s note: Corcoran Consulting Group maintains a comprehensive list of every local Medicare policy for perimetry. You may request this information, free of charge, by contacting us at 800-399-6565 or by visiting our Web site at help@corcoranccg.com

Suzanne Corcoran is vice president of Corcoran Consulting Group. She can be reached at (800) 399-6565.