Early Detection of Diabetic Retinopathy in the Primary Diabetes Care Setting

Only half of all eligible diabetic patients were examined for DR in 2002.
By Neil Brooks, MD

The importance of this message resonates in The National Diabetes Quality Improvement Alliance (www.nationaldiabetesalliance.org), a body comprising multiple specialty medical societies and patient organizations that endorse a clinical performance measurement set including compliance with an annual eye examination and other critical measures.

2003 REPORT

Its 2003 report suggested that only 8 million of the 16 million eligible individuals were examined for DR in 2002. While many individuals with diabetes see a primary diabetes care physician on a regular basis, they do not have the recommended eye evaluation at visits. Although these patients may be referred to an ophthalmologist, many do not follow-up on the recommendation to visit an ophthalmologist or retinal specialist.

Vision loss from DR is usually preventable. Improved glycemic, lipid and blood pressure control are achievable through medication and educational programs.^4,5 Laser photocoagulation is recommended for eyes with severe disease including proliferative diabetic retinopathy. These represent steps to minimize the risk of further progression of the disease with possible vision impairment and blindness.⁶ For example, Vijian et al⁷ studied the efficacy of glycemic control in type 2 diabetes and found that in patients diagnosed before age 50, reducing  HbA1c from 9% to 7% would decrease the lifetime risk for blindness due to retinopathy from 2.6% to 0.3%. For onset of type 2 diabetes after age 65, the risk would be reduced from 0.5% to <0.1%.

INEVITABLE PROGRESSION

In addition, there are pharmacological therapies in clinical trials that may slow or stop the inevitable progression of DR. All rely on prevention of progression of retinopathy, prior to the onset of visual loss. Regular retinal examinations are integral to the medical and surgical management of this potentially disabling condition. It is imperative that methods be found that will allow patients with diabetes to obtain necessary retinal evaluations.

There are many reasons why appropriate eye examinations are not performed. Lack of accessibility to eye care professionals, time constraints, cost and inadequate counseling by primary care providers are all potential hurdles.

In order to capture the approximately 8 million unexamined individuals, several groups have developed procedures that meet the requirements for screening examinations that can be performed in a primary care, endocrinologist or multispecialty office. This is based on the fact that most individuals with diabetes regularly visit their primary care physician or diabetic specialist.

Several groups have developed procedures for eye examinations that can be conducted in medical office settings without on-site ophthalmologic supervision (Table 1). While procedures differ, they generally operate the same (Table 2). A series of photographic images are taken, recorded digitally, and then sent to qualified readers who assess the images and report their findings back to the primary care physician.

Primary care and medical specialists will need to understand how a photographic examination of the retina fits into the care of the diabetic patient. First, it is considered a reliable screening tool for retinopathy, but it will not evaluate other problems such as glaucoma or cataracts, which occur with increased frequency in diabetic patients. The medical provider will relay the findings of the office-based retinal examination to the patient and refer appropriately. Greater involvement in the ocular health of patients with diabetes will require that primary care providers and endocrinologists understand the stages of retinopathy and the likelihood of vision threatening progression.

While the current standard for care of the patient with diabetes is a dilated eye examination by a qualified optometrist or ophthalmologist, 7-field stereo color photography is the gold standard for clinical studies involving DR. Studies are now available comparing these new procedures to standard 7-field fundus photography. In these new systems, experienced retinal image readers evaluate the digital images under the supervision of ophthalmologists and make a decision regarding the need for referral and further evaluation. For example, staff at the Wilmer-EyeTel Reading Center, under the supervision of retinal specialists at The Wilmer Eye Institute at Johns Hopkins, processes the digitized EyeTel images obtained with the EyeTel DigiScope. Similar procedures are used by other systems.

Both office-based retinal examination methods intend to improve accessibility and convenience for patients with diabetes, and thus increase the rate of recommended screening. Initial studies support this assumption. However, there are significant differences between the services offered by these groups, and some are reflected in Table 2. Table 3 suggests questions that might be asked by those considering use of these services.

Vision loss from DR is largely preventable and treatable. Given that nearly all patients with type 1 diabetes and over 60% with type 2 diabetes develop DR, there is a compelling need to change the current pattern of poor compliance with recommendations for regular eye examinations.⁸ In-office methodologies will improve accessibility to cost-effective screening examinations and will change the paradigm to a shared responsibility and increased understanding of this devastating microvascular complication among diabetes care providers. A recent United Healthcare of Texas letter summarizes: “Barriers to accessing specialty health care are well known, and translate into low rates of screening eye examinations. Many patients with diabetes never walk into an eye clinic until they are symptomatic, and at that stage, visual outcomes may be compromised. Digital screening programs do not replace comprehensive eye exams, but rather ensure that those patients are identified at a time when diabetic retinopathy is most amenable to treatment. Digital retinal examination performed by the primary physician will capture many more patients not likely to be seen by an ophthalmologist or optometrist. Introducing digital retinopathy exam capability within your physician practice will facilitate the detection of retinopathy in settings more convenient to the patient.” (United Healthcare of Texas, letter, October 19, 2004).

Collaboration in managing DR will be enhanced as primary diabetes care physicians become more involved in the ocular health of their patients. The convenience for patients will enable a larger percentage of patients to reach the goal of annual retinal eye examinations.

Neil Brooks, MD, is a primary care physician in private practice in Vernon, Conn. He is the chair of the medical/scientific advisory board of EyeTel Imaging, Inc and is a paid advisor to the company. He is a member of the editorial board of Diabetic Microvascular Complications Today. He can be reached at 860-729-1830 or Nbrooksmd@aol.com.

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