glaucoma
Managing Glaucoma
Here is a step-by-step approach to managing patients with glaucoma in your practice
BY DEEPAK GUPTA, O.D., F.A.A.O., Stamford, Conn.

Optometrists are managing glaucoma in virtually all 50 states, so it's imperative that we keep up with the latest in medical technology to provide the best care for our patients. Let's discuss the aspects of patient care that we must address with all glaucoma and glaucoma suspect patients.

1. Reviewing the patient

Include a chief complaint, history of physical illness, review of systems, medical history, family history and psychosocial history when performing a comprehensive evaluation of a new patient (92004) or of an established patient (92014). Include specific exam components such as an assessment of the visual system, slit lamp examination, measurement of IOP and optic nerve and nerve fiber layer examination after pupil dilation.

Once you've identified the risk factors for glaucoma, you may order subsequent tests and diagnostic procedures as part of the work up. When doing this, your chart documentation must include an order for the tests requested by the treating doctor. This may merely be a short phrase indicating "order visual field in one to two months" or "gonioscopy/fundus photos performed today."

Once the appropriate individual performs this particular test, you must document an interpretation of the results somewhere in the chart. A short statement indicating if a test is "normal," "stable from a previous test" or "mild superior arcuate defect" will usually suffice. Include this interpretation on a separate page from the examination record, part of the assessment-plan list, or merely written on the test result directly. The major criteria for these tests are that you must use the results of any test or diagnostic procedure you order to manage the disease.

2. Following up

Once you've diagnosed a patient with glaucoma, see him every three months for an intermediate exam (92012) to check his IOPs.

3. Performing gonioscopy

Visual examination of the anterior chamber angle (gonioscopy, 92020) is a valuable and essential tool for the proper diagnosis and management of glaucoma. Gonioscopy has become part of the standard of care for a glaucoma work up; therefore, the initial evaluation of any newly diagnosed glaucoma or glaucoma suspect patient is complete only if it includes gonioscopic examination. Not only that, but proper long-term management of glaucoma requires gonioscopy at appropriate intervals because the configuration of the angle can change over time. One of the reasons for this is that the angle is influenced by changeable factors such as pupil size, ciliary tone, iris configuration and crystalline lens size. In a stable glaucoma patient who's at or below target IOP and stable visual fields, repeat the evaluation every one to two years. In a patient who has neovascular glaucoma or pigmentary glaucoma, repeat more often.

In terms of billing, gonioscopy is a bilateral procedure. In most cases, you can perform it on the same day as the comprehensive eye exam. Many practitioners often overlook the procedure because they don't deem it necessary. However, they should perform it periodically for the following several reasons:

► It's part of the standard of care.

► What we loosely refer to as glaucoma is actually open-angle glaucoma -- so you can't call it that unless you've visualized the angle and know that it's open.

► It's a legitimate billable expense for glaucoma and glaucoma suspect patients.

4. Evaluating visual fields

Visual field evaluation has been a vital aspect of the diagnosis and management of glaucoma. Although many methods have been developed to assess visual function in glaucoma and glaucoma suspect patients, perimetric evaluation of the glaucomatous visual field remains a cornerstone in the protocol. Because patients are often unaware of peripheral vision loss, especially because the loss is gradual and painless, even the most careful of histories may not help to identify early ocular pathology or yield any significant symptoms experienced by the patient.

The same codes apply for some of the newer technologies in visual field testing, such as frequency doubling threshold (FDT). Because FDT is quick and easy to use, many practitioners order this test as a screening test for high-risk patients. You can bill it as ICD Code 92081 (low level visual field). If the FDT demonstrates any abnormalities, order a more traditional full-threshold test.

CPT defines visual field tests as unilateral or bilateral. Therefore, if you're only doing one eye, you should attach a modifier denoting that when you bill. Also, under the National Correct Coding Initiative (NCCI), visual fields aren't bundled with any other tests, so you can perform them on the same day as gonioscopy and a complete eye examination. However, most insurers won't provide reimbursement if you perform a visual field test on the same day as scanning computerized ophthalmic diagnostic imaging (92135).

As with any test you order, always make a note in the chart for both ordering of this test and the results once you've administered it. Also keep in mind that visual field testing is permitted more than once a year if the situation dictates.

For example, it's commonplace for the visual field test to be repeated if the first field demonstrates glaucomatous defects or significant changes from previous tests. The purpose of the second test is to verify the test results and check for repeatable defects. In this case, bill both as the 92083.

Also, in advanced glaucoma or patients who have IOP under poor control, it may be necessary to perform this test every six months, or, rarely, every three months. As long as documentation is proper and you can justify this, it should be okay.

5. Photographing the fundus

Obviously the optic nerve head is a vital part of the diagnosis and management of glaucoma. In the past, practitioners frequently penciled in drawings of the optic nerve head for their glaucoma and glaucoma suspect patients. This practice is no longer viable, however. In fact, stereo photography of the optic nerve head structure is the minimum standard of care for any such patient. This photography can take place in the form of actual photographs, which are kept in the patient chart or digital images. If the digital images are stored on a disc or a place separate from the patient's chart, you should document the place of that storage.

Fundus photography is considered a bilateral procedure. In most cases, you can't perform it on the same day as scanning computerized diagnostic imaging. In some cases, you can't perform it on the same day as visual field testing.

6. Imaging

The diagnosis and management of glaucoma depend heavily on assessing the appearance of the optic disc. Clinicians have traditionally used subjective parameters, such as the cup-to-disc ratio, along with estimates of the disc size and fundus photography to determine the presence of glaucoma and to detect progression of glaucomatous damage.

In recent years, we have new technology in optic nerve imaging. Specifically, four instruments (the HRT, GDx, OCT, and RTA) that analyze the optic nerve, its surrounding peripapillary tissue or nerve fiber layer are commercially available. Some of these new machines have rapidly been incorporated into standards of care in glaucoma workups.

The purpose of these instruments is to prove objective, reproducible measurements for the posterior pole and optic nerve structure. In doing so, they make it easier to detect subtle changes that might otherwise go unnoticed. Regardless of the type, all four machines work effectively to compliment perimetric (functional) information and help us gain a more complete picture in the diagnosis and management of glaucoma.

Scanning computerized ophthalmic diagnostic imaging (92135) incorporates all four of the major instruments (listed previously). Bill as a unilateral procedure, but if you do both eyes, then bill each eye separately with a right and left modifier.

7. Measuring IOP

Even though we no longer consider glaucoma a disease of high eye pressure, the measurement of IOP is an essential part of the ocular exam in a glaucoma or glaucoma suspect patient. Tonometry is considered serial when you measure IOP at least three separate times during the course of one day. Eyecare practitioners have shown a renewed interest in performing this test (92100) because of the research highlighting the large fluctuations in diurnal IOP that may hinder glaucoma diagnosis and management. The typical protocol for this procedure is to have the patient at the office every hour all day for IOP checks. This test is most commonly used in patients who have suspected normal tension glaucoma.

8. Corneal pachymetry

The pachymeter has historically been used to measure corneal thickness for assessing corneal health related to ocular pathology. This instrument gained increased importance with many optometrists who co-manage refractive surgery patients. More recently, with the release of the Ocular Hypertension Treatment Study, the corneal pachymeter has become part of the standard of care for any optometrist managing glaucoma.

This code (0025T) was recently added to the current procedural terminology (CPT) Category III and is defined as "determination of corneal thickness (e.g., pachymetry) with interpretation and report, bilateral." Unlike many of the other tests which we can perform every year or so, the measurement of corneal thickness can only be performed once in a patient's lifetime.

It's a win-win duty

As primary care providers, we're perfectly able to manage glaucoma. As part of this management, it is our duty to keep up with the latest in technology to better serve our patients. The nice thing about this is that better serving our patients will also better serve our practices.