Accuracy of Screening for Diabetic Retinopathy by Family Physicians

It is refreshing to see an article which directs attention to the skill and importance of observing the retina by the primary care physician. Indeed, ophthalmoscopic technique is an important skill and one which requires training and practice.

I want to call attention to the authors' assertion that certain retinal fields "are usually not visible using a standard direct ophthalmoscope without dilation". To the contrary, it is certainly within the realm of liklihood that a physician can visualize the retina up to 3 or 4 disc diameters from the center of the optic disc with the standard Helmholtz-designed scope without pupillary dilation. We regularly teach this to our clerkship students in an ophthalmoscopic technique workshop, and the large majority are successful in gaining this degree of retinal inspection. We have also discovered that first year medical students are also capable of performing this same degree of retinal inspection. The use of the newer PanOptic scope improves the ease of observing diabetic lesions. But the standard scope also offers great opportunity for visualizing retinal lesions by any physician, specialized or not.

Competing interests:   None declared

Dr. Gill and colleagues address the important issue of screening for diabetic retinopathy. The prevalence of diagnosed diabetes in 1999-2000 was 5.9%, with undiagnosed diabetes representing and additional 2.4% (Cowie, 2003). Past work has estimated that the prevalence of retinopathy at the time of diagnosis of diabetes is 20% (Harris, 1992). As the authors have referenced, screening for diabetic retinopathy with a dilated retinal exam by an ophthalmologist is recommended yearly for people with diabetes. Furthermore, interventions for early diabetic retinopathy can save vision in our patients with diabetes. However, in the 1990’s, only 63.3% of people with diabetes received annual dilated retinal screening (Saadine, et al, 2002). Additionally, the National Committee for Quality Assurance’s (NCQA) Diabetes Physician Recognition Program, designed to recognize excellence in diabetes care, requires that only 60% of the candidate’s self-selected adult panel have had an eye examination in the past year as a mark of distinction for diabetes care providers (http://www.ncqa.org/dprp/).

The cost of a Welch Allyn PanOptic ophthalmoscope head from online retailers is about $450 vs. $150-200 for a conventional ophthalmoscope head. For the roughly 40% of our patients who are not making it to their yearly dilated eye exam visits, this may be a small investment. We’d also have to invest a little time in training, and a little more time at the visits for these patients, but that time could pay off for our patient’s vision. Additionally, I would hypothesize that the same barriers that prevent these patients from attending their recommended eye exams may also be barriers that lead to poor adherence, poor diabetes control, and poor blood pressure control, making these patients the patients most in need of our attention to their eyes.

From a methodological perspective, it may have been more helpful for readers if the family physician use of the panoptic scope had been compared to the true gold standard, the ophthalmologist’s dilated retinal exam, rather than an “intermediate” gold standard, the ophthalmologist’s exam using the panoptic scope. This may be an area for a future investigation. Nevertheless, Dr. Gill and his coauthors have emphasized an opportunity for primary care doctors to take a greater role in the care of the eye in their patients with diabetes, especially those who do not get to the ophthamologist for their yearly exam.

References:

Cowie CC, Rust KF, Byrd-Holt D, Eberhardt MS, Saydah S, Geiss LS, Engelgau MM, Ford ES, Gregg EW. Prevalence of diabetes and impaired fasting glucose in adults---United States, 1999-2000. MMWR 2003;52:833- 837.

Harris MI, Klein R, Welborn TA, Kniman MW. Onset of NIDDM occurs at least 4-7 years before clinical diagnosis. Diabetes Care 1992;15:815-819.

Saadine JB, Engelgau MM, Beckles GL, Gregg EW, Thompson TJ, Narayan KM. A diabetes report card for the United States: quality of care in the 1990’s. Ann Int Med 2002;136:565-574.

Competing interests:   None declared

This study illustrates that family physicians with varied numbers of years of practice experience can be trained in a reasonably short period of time to use a new diagnostic technique with a good degree of accuracy. As a participant in this study, I found the use of the pan-optic ophthalmoscope according to the above mentioned decision rules required a short learning curve. New diagnostic techniques and new instruments can be exciting to family physicians who are several years past their residency training.

The management of diabetic patients has become increasingly complex with the rising number of parameters that need to be monitored and addressed. Is there enough time available in the routine clinical encounter to incorporate another examination technique? In my experience, an examination of the optic fundi with the pan-optic scope similar to those done in this study requires an additional five minutes of time in an encounter already crowded with other requirements. There is no existing mechanism to claim any increase in reimbursement for this increase in clinical work.

My limited clinical time is used more efficiently by having my staff inquire about eye examinations and remind all diabetic patients to see their ophthalmologist yearly.

Competing interests:   None declared