Components of the exam. Initial evaluation by the ophthalmologist or optometrist should include a detailed history and comprehensive eye exam with pupil dilation. Table 24 lists elements of the initial physical exam, which should assess for features that often lead to visual impairment. These features include macular edema, retinal hemorrhage, venous beading, neovascularization, and vitreous hemorrhage.4
Frequency of follow-up. The interval between subsequent examinations should be individualized, based on the findings of the initial assessment. Consider that:
- Screening should occur every 1 or 2 years in patients without evidence of retinopathy and with adequate glycemic control.4,18,23
- Screening every 1 or 2 years appears to be cost-effective in patients who have had 1 or more normal eye exams.
- A 3-year screening interval does not appear to present a risk in well-controlled patients with type 2 DM.24
- Women with type 1 or type 2 DM who are planning pregnancy or who are pregnant should have an eye exam prior to pregnancy or early in the first trimester.4,18,23 They should then be monitored each trimester and at the end of the first postpartum year, depending on the severity of retinopathy.18
Alternative screening modalities
Seven-field stereoscopic fundus photography is an alternative screening tool that compares favorably to ophthalmoscopy when performed by an experienced ophthalmologist, optometrist, or ophthalmologic technician.25 Nonmydriatic digital stereoscopic retinal imaging has been shown to be a cost-effective method of screening patients for diabetic retinopathy.26 In a study that compared digital imaging with dilated funduscopic examination, investigators reported that, of 311 eyes evaluated, there was agreement between the methods in 86% of cases. Disagreement was mostly related to the greater frequency of finding mild-to-moderate NPDR when using digital imaging.27
Screening in primary care
Programs that use telemedicine-based fundus photography to screen for diabetic retinopathy during primary care visits, followed by remote interpretation by an ophthalmologist, have been shown to increase the rate of retinal screening by offering an option other than direct referral to an ophthalmologist or optometrist.28 However, telemedicine-based retinal photography can be successful as a screening tool for retinopathy only if timely referral to an eye specialist is arranged when indicated by findings.18
SIDEBAR
Key points in the progression of diabetic retinopathy care
Duration of diabetes, poor glycemic control, and uncontrolled hypertension are major risk factors for diabetic retinopathy.
To reduce the risk of diabetic retinopathy, patients with diabetes mellitus should:
- sustain good glycemic control (hemoglobin A1C level, < 7%)
- maintain blood pressure < 140/90 mm Hg
- undergo periodic routine screening eye examination.
Early detection of diabetic retinopathy by dilated eye examination or fundus photography can lead to early therapeutic intervention, which can reduce the risk of visual impairment and vision loss.
Treatment is based on severity of disease and can include anti-vascular-endothelial growth factor therapy, photocoagulation, or surgery.
What therapy will your referred patients receive?
Patients found to have signs of diabetic retinopathy should be referred to an ophthalmologist who is knowledgeable and experienced in the management of diabetic retinopathy. Care will be managed according to the severity of the patient’s diabetic retinopathy.
Continue to: Patients with mild-to-moderate NPDR but without macular edema