CLINICAL

  the back

Your Macular Evaluation

Take these steps to preserve your patients’ vision

SHERROL A. REYNOLDS O.D., F.A.A.O., FT. LAUDERDALE, FLA.

Macular disease is on the rise. The NEI estimates that individuals with “wet” or exudative AMD will increase to three million by 2020. Furthermore, it also projects diabetic retinopathy, including diabetic macular edema, to climb to 11 million by 2030.

Clinicians and researchers have made major strides in the early detection of macular disease. In some cases, subtle sight-threatening maculopathy can pose a diagnostic challenge. Even so, timely detection is crucial in the management and progression of macular disease in order to preserve vision.

Here are some ways to enhance your macular evaluation.

1 Core testing

Core testing plays an important role in your macular evaluation. In addition to visual acuity and color vision testing, a number of newer condensing lenses with better magnification and fields of view are available. For example, the macular “pancake” contact fundus lens gives a detailed view, especially when cataracts obscure the view. Also, don’t ignore the central lens of the three-mirror lens.

Determining a pseudohole caused by an epiretinal membrane from a full-thickness macula hole can be done with the slit-beam test. Another test is the under-utilized macular photostress recovery test (MPSRT). It is as simple as shining an intense light source, like an ophthalmoscope, into the affected eye and timing the recovery of visual acuity. A prolonged time (>50 seconds) is found with conditions, like AMD and macular edema.

Macular changes that result in metamorphopsia, visual field scotoma, blurred vision or micropsia are easily detected with an Amsler grid. Self-monitoring with an Amsler grid is important in patients with maculopathy, such as AMD, to alert the patient of visual changes that may indicate the presence of a choroidal neovascular membrane (CNV).

Fundus photography (CPT code 92250) not only aids in diagnosis and management, it captures subtle changes, such as microaneurysms, and macular exudates or thickening that can be missed. It is an extremely valuable patient education tool, as it allows the patient to see the retinal changes, which, ultimately, may lead to better patient compliance.

Finally, practitioners often overlook the value of standard automated visual field testing (CPT code 92083) in managing macular disease. The central 10-2 visual field test is extremely valuable for assessing macular function. For example, the new hydroxychloroquine (Plaquenil, Covis Pharmaceuticals, Inc.) screening guidelines published by the AAO require a 10-2 white-stimulus be performed. A 10-2 visual field is sensitive at detecting subtle paracentral visual field defects, which indicate early macular toxicity.

Macular microperimetry is also available and allows for specific testing of macular function. For example, in AMD, microperimetry can detect early functional changes for atrophy or neovascularization, as well as monitor progression of the disease. CPT code 92083 can be used for a full microperimetry evaluation.

2 Technology

Technology is crucial in the diagnosis and management of macular conditions.

• Spectral-domain optical coherence tomography (SD-OCT). SD-OCT (CPT code 92134) is now considered a standard of care and a must-have technology. OCT has improved our ability to understand, diagnose, monitor and treat a wide range of vitreoretinal conditions, such as vitreomacular traction syndrome, vitreopapillary traction, macular holes and epiretinal membranes. In some cases, SD-OCT may be equal or superior to angiography in helping to make the initial diagnosis (for example, in cases of cystoid macular edema and central serous chorioretinopathy). OCT can also be used to better assess early macular damage in patients taking hydroxychloroquine chronically.

• Fundus autofluorescence (FAF). FAF is a non-invasive imaging modality that detects lipofuscin, a metabolic biomarker of disease in the retinal pigment epithelium (RPE). At this time, no CPT code exists solely for FAF imaging, but it can be billed as part of fundus photography using the 99250 CPT code. Please note that you cannot bill for both if performed the same day. Some imaging companies recommend providers use CPT code 92499 (unlisted ophthalmological service) to identify FAF on claims.

• Macular pigment optical density (MPOD). With the explosion of nutritional supplements that contain lutein and zeaxanthin, measurement of an eye’s MPOD enables clinicians to identify patients at risk for AMD and gauge the effects of dietary changes and supplementation. MPOD testing does not have a CPT code and is not billable to insurance.

• Multispectral imaging (MSI). MSI allows visualization of the retina in spectral slices, from the inner limiting membrane all the way through the choroid. MSI has the ability to assist in the diagnosis of diabetic retinopathy, cystoid macular edema, AMD and conditions that masquerade as AMD, such as polypoidal choroidal vasculopathy (PCV). It is also available with FAF capability. MSI is not covered by insurance.

• Multifocal electroretinography (mfERG). This provides a detailed assessment of the health of the central retina. It is also recommended in the new screening guideline for hydroxychloroquine. There is no specific code for mfERG, but CPT code 92275 can be used for electroretinography with interpretation and report.

• Preferential hyperacuity perimetry (PHP). PHP (Notal Vision, Reichert Technologies) is a computer-based screening test that utilizes hyperacuity (Vernier acuity) to test the central 14° of the visual field. PHP enables you to monitor patients who have dry AMD for conversion to wet AMD. The Foresee PHP instrument comes in both an office-based version and a version that is designed for at-home use. In-office testing is billable with a diagnosis of AMD as an intermediate visual field.

3 Referrals

In certain instances, such as an occult CNV, despite the advent of ever-improving OCT technology, there is still a need for referral to a retinal specialist for fluorescein angiography (IVFA) and Indocyanine Green angiography (ICG). These are invasive tests that require the intravenous injection of dye. They come with an extremely small, yet real, risk of significant complications, including anaphylactic response. In some states, these tests may be performed and/or ordered by optometrists, but in other states they may not.

IVFA and ICG tend to have some advantages over OCT when evaluating vascular conditions, such as CNV, neovascularization and capillary dropout, with ICG being preferable for choroidal conditions, such as PCV.

Optometry’s role

Optometry is at the fore-front of detecting and managing macular disease. Therefore, it is imperative to take appropriate action to prepare your practice now. Not doing so may result in you being unable to effectively care for your patients, potentially forcing them to seek care elsewhere. OM

Brad Sutton, O.D., F.A.A.O., a clinical professor at Indiana University School of Optometry, chief of service at Indianapolis Eye Care Center, and president of ORS, contributed to this article.

Dr. Reynolds is an associate professor at the Nova Southeastern University College of Optometry. She is the clinical preceptor/attending in the college’s diabetes and macular clinic and a fellow of ORS. To comment, visit tinyurl.com/OMcomment.