Article Figures & Data
Tables
Uninterpretable (inadequate) photographs Severe diabetic retinopathy as evidenced by any of the following: Diffuse intraretinal hemorrhage in all 4 quadrants Any hard lipid exudate present within 1/3 disc diameter of fovea An optic-disc-sized patch of hard lipid exudate, any part of which is within 1 disc diameter of the fovea Venous beading present in 2 quadrants Any intraretinal microvascular abnormalities Any neovascularization Any vitreous hemorrhage Other abnormalities, including retinal scarring or past laser surgery Any unknown abnormalities - Table 2.
Results of Photograph Interpretations (n = 1,040) by Primary Care Clinician and Ophthalmologist
Reading Outcome, All Patients Ophthalmologist Primary Care Clinician Sensitivity Specificity PPV NPV NPV = negative predictive value; PPV = positive predictive value. a For identification of any diabetic retinopathy, regardless of whether it needed referral. b Other abnormalities include laser and other retinal scarring. c Some patients were referred for more than 1 finding, but each patient referred was counted only once. Diabetic retinopathy, overalla 113 156 0.85 0.94 0.62 0.98 Vitreous hemorrhage 5 7 1.0 0.997 0.71 1.0 Intraretinal microvascular abnormality 5 3 0.2 0.998 0.33 0.996 Venous beading 6 11 0.50 0.995 0.27 0.997 2 quadrants 4 9 0.50 0.99 0.22 0.99 Intraretinal hemorrhage 98 90 0.73 0.98 0.80 0.97 Diffuse 4 6 0.75 0.99 0.50 0.99 Neovascularization 5 4 0.4 0.997 0.50 0.998 Lipid exudates 56 108 0.96 0.95 0.50 0.99 1/3 disc diameter 39 52 0.82 0.98 0.62 0.99 Disc diameter 16 29 0.94 0.99 0.52 0.99 Referred for other abnormalityb 39 26 0.66 0.97 0.38 0.96 Referred for diabetic retinopathy 46 69 0.89 0.97 0.59 0.97 Referred for inadequate photograph 302 296 0.87 0.96 0.89 0.95 Referred, totalc 344 356 0.90 0.93 0.87 0.95 Abnormality Missed No./Denominatora(%) a Denominator is the number of referrals for each category made by the retinal specialist. b Clinicians missed severe diabetic retinopathy in 5 cases; 1 patient was referred for inadequate photograph and does not count as missed referral. Inadequate photograph 18/302 (6.0) Other abnormality needing referral (total) 13/39 (33.3) Abnormal cup-to-disc ratio 5 Severe arterial attenuation and tortuosity 1 Unknown abnormality 3 Choroidal nevus 2 Small optic nerve 1 Arterial plaque 1 Diabetic retinopathyb 4/46 (8.7) Total missed referrals 35/344 (10.1) Clinic (Access Model) No. Screened No. of Patients With Diabetes Mellitus Screening Rate PValuea a For 95% confidence interval of rates, compared with C1, using χ2 analyses. C1 (permanent) 314 673 47 NA C2 (twice yearly) 261 587 44 .436 C3 (twice yearly) 114 297 38 .017 C4 (twice yearly) 130 519 25 <.001 C5 (refer in) 95 368 26 <.001 C6 (refer in) 30 142 21 <.001 Total 944 2,586 37 <.001
Additional Files
Supplemental Figures
Supplemental Figure 1. Retinal photograph showing venous beading (vb) and intraretinal microvascular abnormality (IRMA), missed by primary care clinician reader; Supplemental Figure 2. Retinal photograph showing lipid exudates within 1/3 disc diameter of fovea missed by primary care clinician reader.
Files in this Data Supplement:
- Supplemental data: Figure 1 - PDF file, 1 page, 174 KB
- Supplemental data: Figure 2 - PDF file, 1 page, 98 KB
The Article in Brief
Tillman F. Farley , and colleagues
Background Early detection and treatment of diabetic retinopathy, an eye disease common in people with diabetes, can slow or prevent the development of blindness. Screening for diabetic retinopathy usually involves an ophthalmologist (eye specialist), but low-income patients may have limited access to such specialists. Researchers have tested a screening program in which primary care doctors are trained to read a single image taken with a retinal camera, a tool that can identify diabetic retinopathy. This study looks at the doctors' accuracy in reading the photographic images and correctly identifying patients needing referral to ophthalmologists.
What This Study Found Primary care doctors trained to read single images from a retinal camera have acceptable accuracy in screening for diabetic retinopathy. They screened 1,040 diabetic patients at a low-income health center. One hundred thirteen (10.9%) were found to have diabetic retinopathy, 46 severe enough to need referral to an ophthalmologist. Participating doctors missed diabetic retinopathy in 8.7% of the patients who had it (4 out of 46), but discovered it in 41 others. Of the 344 patients the ophthalmologist believed needed referral, primary care doctors failed to refer 35 (10.2%), usually because the doctor failed to recognize an inadequate photograph or abnormalities other than diabetic retinopathy.
Implications
- Using single-image retinal photography in primary care offices, with primary care doctors reading the images, may be a cost-effective way to help reduce vision loss in diabetes patients who have limited access to ophthalmologists.
- Further training may be needed to help primary care doctors recognize other common eye problems.