Recently, a colleague wrote me to express his concern about a primary care physician (PCP) in his community acquiring digital retinal photographs of his diabetes patients. One of those patients presented to the optometrist’s office with the impression that “all he needed was a refraction” since the PCP had “already checked him for diabetic retinopathy.”
This made me wonder how many other optometrists are facing this predicament. I suspect this is a circumstance eyecare providers may increasingly encounter as economic pressures push insurers and providers to efficiently deliver care and consolidate control over the breadth and scope of health care encounters (i.e. do more with less money and fewer visits).
Dilated ophthalmoscopy instead of a screening
Part of the argument for “diabetic retinopathy screening” derives from the fact that significant minorities of people with diabetes still are not receiving recommended annual dilated eye examinations by optometrists and ophthalmologists.1 In addition, there also may be the perception that rates of severe diabetic retinopathy are low, an argument countered by studies showing that as many as 1 in 20 adults with diabetes have vision-threatening retinopathy2 (nearly 1 in 15 Latino Americans, and 1 in 10 African Americans).
I totally advocate digital retinal imaging for purposes of identifying diabetic retinopathy in underserved populations, provided these images are interpreted by trained observers. Moreover, this technology is invaluable for patient education, documentation of findings, and sometimes even staging and diagnosis of disease. (Let’s face it, some patients are more tolerant than others when it comes to letting us scrutinize their retinas during dilated fundus examination. Finding any/every microaneurysm in a photophobic patient with diabetic retinopathy can be challenging, and red-free digital imaging can be enormously helpful even to experienced clinicians). However, we all know that conventional digital retinal imaging is no substitute for dilated ophthalmoscopy in patients with diabetes for a number of very good reasons.
First, retinal imaging doesn’t allow stereoscopic assessment of the retina or optic nerve. We frequently see patients with diabetic macular edema or glaucoma but exhibiting relatively normal-appearing fundus images. In the absence of stereoscopic exam and/or OCT, these cases would not be diagnosed or managed appropriately.3
Second, as a stand-alone technique, retinal imaging may not allow early detection of many common eye conditions associated with diabetes, including cataract, glaucoma, ocular surface disease, lid disease, refractive fluctuation signaling unstable diabetes control, and cranial nerve paresis and palsy. Every optometrist and ophthalmologist knows there is much more to diabetic eye disease than “just” diabetic retinopathy.4
Third, retinal imaging is insufficient to identify the etiology of retinal findings in a patient with diabetes; we must also rule out other possibilities (e.g. hypertension, venous occlusive disease, even ocular ischemic syndrome) with trained and practiced clinical acumen. Instruments and their associated technologies do not make diagnoses, nor do they exercise clinical judgment—only an experienced and knowledgeable eyecare specialist, skilled with both the acquisition and the interpretation of the information gleaned from those instruments and technologies, can make the right diagnosis and use sound clinical judgment based on the entirety of patient information, including case history.