Practical Tips for Imaging the Posterior Segment
Practical Tips for Imaging the Posterior Segment
Technology has revolutionized how we view the retina, allowing optometrists to bring new levels of care to patients.
JEFFRY D. GERSON, O.D., F.A.A.O., SHAWNEE, KAN.
Just as the world of imaging through traditional cameras has been revolutionized with technology, so has ophthalmic imaging and, specifically, posterior segment imaging. Gone are the days when most of us use a traditional “picture” to follow our patients. Whether it be fundus autofluorescence (FAF), widefield imaging, spectral domain OCT (SD-OCT) or something else, most of these devices have as many options and “bells and whistles” as any electronic device. Retinal imaging goes well beyond color photography. This article discusses some of the available and practical technologies/devices along with advice on how to utilize them.
Don’t overlook lenses
Before delving into these advancements, remember the single most important part of an eye exam: the clinical examination, that is, using a slit lamp with condensing lenses, binocular indirect ophthalmoscopy (BIO) and listening to patients when taking their history. One overlooked segment of technology for posterior segment examination is the advancement of condensing lenses. If you still use the 78D lens from school that rattles, consider an upgrade. Newer lenses for both the slit lamp and BIO allow for either a larger view of the field without the loss of magnification or more magnification without losing field. Just as our patients can take advantage of “digital” progressive lenses, “digital” condensing lenses can aid in our clinical exam.
Cost: no longer a barrier
In terms of cost, it no longer takes a large multidoctor practice to afford the latest imaging technology. A “traditional” fundus camera can now be bought for less than $15,000. The most affordable camera may be an adapter that attaches your smart phone to an ophthalmoscope to capture retinal images. Of course, the more features a camera tends to have, the more it likely costs.
One obstacle in obtaining equipment is always cost and determining ROI. Before buying our last imaging device, we forecasted ROI by keeping track for three months of the number of patients we saw that would both benefit from imaging and create a billable event. Through this calculation, the financial viability quickly became apparent.
Something that helps ROI is the potential to bill for both fundus photography (CPT code 92225) and OCT (CPT code 92133) on the same visit when appropriate diagnosis codes are used. Although Florida is the only state that has set specific rules for this reimbursement, other states are likely to soon follow. Note that there are also states where most insurance plans do not allow you to bill for both fundus photography and OCT in the same day. So it is imperative you check with your local carriers for details and clarification for modifiers.
As mentioned above, fundus cameras can be bought for a very reasonable price. In assessing this technology, the real question is: What features do you want? The potential to have widefield imaging of the peripheral retina greatly enhances the amount of pathology you can detect and bill for, as compared with imaging the posterior pole alone. Some offices use widefield imaging as a screening device and help base decisions pertaining to dilation on results. Although imaging does not take away the need for mydriatic exams, it may be a great tool for helping to decide the frequency and necessity of them.
“Segmenting” retinal layers
Another important tool available on most cameras is the ability to “segment” layers of the retina. At the very least, this is done by using red-free images to show superficial pathology. This segmentation can help detect very subtle hemorrhages in diabetic patients who may not even know that they have diabetes. Some cameras allow for virtually hands-free capture and may help with image acquisition.
Another camera quality that may interest some is either an integrated OCT/camera unit or, at least, a camera that superimposes its image over an OCT image of the same patient. This feature can help in determining how different modalities correlate and work together to aid in diagnosis and follow-up.
The FAF spin
A totally different spin on imaging is fundus autofluorescence (FAF). A few years ago, this was solely a research-based technology. Several companies now offer commercial units. Essentially, FAF shows metabolic activity of the retinal pigment epithelium (RPE). Completely different than any other technology available, FAF has wide-ranging applications. For example, some ongoing studies on geographic atrophy use FAF as one of the endpoints for analysis. In the recently published AREDS2 study results (the study assessed patients who were at risk for advanced AMD), it may have been helpful to know whether FAF, which was utilized with a subset of the study’s patients, played any role in the detection of AMD progression.
Image courtesy of Optos
Shown is an ultra-widefield fundus autofluorescence image of a choroidal melanoma extending into the peripheral retina.
Further, widefield FAF may be very helpful in detecting disease before it ever affects the macula. Wouldn’t it be great if we could detect peripheral FAF changes that we knew correlated to AMD, and start preventative measures earlier and never allow the formation of true “AMD” as we think of it? Studies show that this may be the case.
In general, FAF represents a good investment for those practices at which there is a large population disposed to AMD (patients ages 50 and older).
Plaquenil maculopathy and imaging
Although some imaging technologies are not new, such as SD-OCT, new uses for them that have incredibly practical applications are coming up all the time. For instance, when the most recent set of guidelines came out for screening for hydroxychloroquine (Plaquenil, Sanofi-Aventis) maculopathy, an article stated that patients need to be tested with at least one of the following: FAF, SD-OCT or multifocal ERG. Literally hundreds of thousands of patients are prescribed Plaquenil, which is indicated for lupus and rheumatoid arthritis. This presents a terrific opportunity to help build a relationship with rheumatologists or others managing the auto-immune disease requiring this drug. While receiving reimbursement for this testing is sometimes a challenge, the extra referrals we receive for the testing associated with Plaquenil maculopathy — including consultations/examinations and visual field perimetry (for 10-2) — has, indirectly, more than paid for any insurance problems.
Neurodegenerative disorders and SD-OCT
Another emerging use for SD-OCT is within the neurology community. Facets of neurodegenerative diseases, such as multiple sclerosis, may be best monitored through SD-OCT. In particular, ganglion cell complex analysis may be of further special interest in these neurologic issues. Again, there is excellent potential for building a relationship with community M.D.s and neurologists, in particular, when they know you have an OCT and can help their patients. Consider these inexpensive and easy methods for “spreading the word” about your practice and the technological advantages of your practice’s SD-OCT:
► Send a letter of introduction to neurologists and those M.D.s in your area whom you feel should know about the capabilities of your SD-OCT. State that, you understand the SD-OCTs potential benefits for neurological care and that you welcome the opportunity to scan the neurology practice’s patients.
► When you see a patient who also visits a neurologist, be sure to send the M.D. a copy of the patient’s SD-OCT.
The injectable treatment, ocriplasmin (Jetrea, Thrombo-Genics), was recently approved for inducement of posterior vitreous detachment (PVD) and closing of macular holes. Besides vitrectomy, there are no other treatments for this condition. Clinicians can use SD-OCT to prove both a PVD has occurred and that a macular hole has closed or improved.
Although a fairly small percentage of our patients develop macular holes, AMD is a much more prevalent pathology. The most recent drug approved, aflibercept (Eyelea, Regeneron), showed among other things, improvement in OCT findings in patients with wet AMD. After initial treatment in AMD, future treatments of the injectable drug may be dependent on changes seen on SD-OCT as much as anything else, sometimes before changes in vision occur.
Most likely FAF will continue to play a more important role in AMD, as it is a way to really identify whether there is change invisible to ophthalmoscopy/photography and SD-OCT. As retina specialists become more and more burdened with injections for AMD and other conditions, it is likely that they will rely on O.D.s who have SD-OCT and other advanced imaging modalities to help determine when patients need further treatments. This presents not only an opportunity for our offices, but also for our patients. I would imagine most of our patients would prefer follow-up visits in our offices as opposed to an overburdened retina practice where the wait times are likely to be longer.
Besides providing good care for our average patients, the technologies mentioned above are also of paramount importance for patients with pathology. A number of recent publications rely on these imaging technologies to confirm treatment efficacy. For example, the AREDS2 study utilized both SD-OCT and fundus photography, with a subset of patients receiving FAF imaging.
MPOD and “visual excellence”
Although not truly imaging technology, devices that measure macular pigment optical density (MPOD) are worth mentioning. Most of our patients come to us for enhancement in their vision, and not for ocular disease. Often times through supplementation, we can improve MPOD and improve vision, whether measured by acuity, contrast, night-time driving ability or other metrics.
The economics of MPOD can also potentially be very beneficial for the O.D. Many practices charge a nominal fee for performing the test, and most of them also sell vitamin/nutritional supplements that contain lutein and zeaxanthin for patients who have low levels of these macular pigments. This is an added revenue stream and a way to potentially impact the quality of a patient’s vision. Think of this as promoting “visual excellence.”
Making the case
In making the case for investment in modern technologies, we are also making the case to fellow professionals to allow us to care for our patients to the fullest extent. In doing this, we are likely to garner referrals from different sources — maybe even other O.D.s who have not chosen to “take the plunge” yet. The best care for our patients presents the best opportunities for our practices. Of even more interest is what the future holds and what we will be using 10 years from now. OM
Dr. Gerson is in private practice at WestGlen Eyecare and Omni Eye Center of Kansas City, Kan. E-mail him at email@example.com. To comment on this article, e-mail firstname.lastname@example.org.
Optometric Management, Volume: 48 , Issue: July 2013, page(s): 16 17 18