Diabetic Retinopathy and the Cascade into Vision Loss.

Vision loss from diabetic retinopathy should be unnecessary for patients with access to diabetic retinopathy screening, yet it still occurs at high rates and in varied contexts. Precisely because vision loss is only one of many late-stage complications of diabetes, interfering with the management of diabetes and making self-care more difficult, Vision Threatening Diabetic Retinopathy (VTDR) is considered a "high stakes" diagnosis. Our mixed-methods research addressed the contexts of care and treatment seeking in a sample of people with VTDR using safety-net clinic services and eye specialist referrals. We point to conceptual weaknesses in the single disease framework of health care by diagnosis, and we use the framework of "cascades" to clarify why and how certain non-clinical factors come to bear on long-term experiences of complex chronic diseases.

A Revised Approach for the Detection of Sight-Threatening Diabetic Macular Edema.

IMPORTANCE: Diabetic macular edema is one of the leading causes of vision loss among working-age adults in the United States. Telemedicine screening programs and epidemiological studies rely on monoscopic fundus photography for the detection of clinically significant macular edema (CSME). Improving the accuracy of detecting CSME from monoscopic images could be valuable while recognizing the limitations of such detection in an era of optical coherence tomography detection of diabetic macular edema. OBJECTIVE: To evaluate the screening test accuracy of radially arranged sectors affected by hard exudates in the detection of CSME. DESIGN, SETTING, AND PARTICIPANTS: This investigation was a cross-sectional study of CSME grading in monoscopic images using a sectors approach. The Early Treatment Diabetic Retinopathy Study criteria were used to confirm the presence of CSME by the following 2 methods: stereoscopic fundus photography (method 1) and dilated biomicroscopy in combination with optical coherence tomography (method 2). Participants were recruited at a university-based practice between June 14, 2014, and December 28, 2015. MAIN OUTCOMES AND MEASURES: Area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: A total of 207 eyes from an ethnically/racially diverse group of 207 patients (mean [SD] age, 53.6 [10.8] years; 58.9% [122 of 207] female) were included in the analysis. Twelve eyes (5.8%) were diagnosed as having CSME based on method 1. The intermethod and intergrader agreement for CSME diagnosis and sector count was substantial (κ range, 0.66 [95% CI, 0.47-0.85] to 0.75 [95% CI, 0.53-0.97]; P < .001 for all). Area under the receiver operating characteristic curve was 93.2% (95% CI, 84.2%-100%) when evaluating a sectors approach against method 1 as a reference test and offered up to an 8.6% (95% CI, 3.0%-14.3%) increase in specificity compared with the existing methods of detection. The positive predictive value was 33.3% (95% CI, 25.6%-45.5%), and the negative predictive value was 98.1% (95% CI, 96.9%-100%). The results were similar when comparing a sectors approach with method 2 as a reference test. CONCLUSIONS AND RELEVANCE: A sectors approach shows good screening test characteristics for the detection of CSME. Its implementation in the existing telemedicine programs would require minimal resources. This approach will have the greatest effect in a setting where implementation of optical coherence tomography, a more objective and sensitive way to detect retinal thickening, is not feasible. The proposed method also may be easily incorporated in the automated diabetic retinopathy detection algorithms.

Improving Accuracy of Grading and Referral of Diabetic Macular Edema Using Location and Extent of Hard Exudates in Retinal Photography.

BACKGROUND: Hard exudates (HE) are used as a surrogate marker for sight-threatening diabetic macular edema (DME) in most telemedicine-based screening programs in the world. This study investigates whether proximity of HE to the center of the macula, and extent of HE are associated with greater clinically significant macular edema (CSME) severity. A novel method for associating optical coherence tomography (OCT) scans with CSME was developed. METHODS: Eligible subjects were recruited from a DRS program in a community clinic in Oakland, California. Ocular fundus of each subject was imaged using 3-field 45-degree digital retinal photography and scanned using central 7-line spectral domain OCT. Two certified graders separated subjects into 2 groups, those with and without HE within 500 microns from the center of the macula. A modified DME severity scale, developed from Early Treatment Diabetic Retinopathy Study data and adapted to OCT thickness measurements, was used to stratify CSME into severe and nonsevere levels for all subjects. RESULTS: The probabilities of severe CSME in groups 1 and 2 were 14.4% (95% CI: 8.2%-23.8%) and 9% (95% CI: 2.4%-25.5%), respectively (P = .556). In post hoc analysis, increase in the number of sectors affected by HE within the central zone of the macula was associated with the increase in the probability of being diagnosed with severe CSME. CONCLUSION: We have proposed OCT-based classification of DME into severe and nonsevere CSME. Based on this limited analysis, severity of CSME is related more to extent of HE rather than proximity to the center of the macula.

Utility of hard exudates for the screening of macular edema.

PURPOSE: The purpose of this study was to determine whether hard exudates (HEs) within one disc diameter of the foveola is an acceptable criterion for the referral of diabetic patients suspected of clinically significant macular edema (CSME) in a screening setting. METHODS: One hundred forty-three adults diagnosed as having diabetes mellitus were imaged using a nonmydriatic digital fundus camera at the Alameda County Medical Center in Oakland, CA. Nonstereo fundus images were graded independently for the presence of HE near the center of the macula by two graders according to the EyePACS grading protocol. The patients also received a dilated fundus examination on a separate visit. Clinically significant macular edema was determined during the dilated fundus examination using the criteria set forth by the Early Treatment Diabetic Retinopathy Study. Subsequently, the sensitivity and specificity of HEs within one disc diameter of the foveola in nonstereo digital images used as a surrogate for the detection of CSME diagnosed by live fundus examination were calculated. RESULTS: The mean (±SD) age of 103 patients included in the analysis was 56 ± 17 years. Clinically significant macular edema was diagnosed in 15.5% of eyes during the dilated examination. For the right eyes, the sensitivity of HEs within one disc diameter from the foveola as a surrogate for detecting CSME was 93.8% for each of the graders; the specificity values were 88.5 and 85.1%. For the left eyes, the sensitivity values were 93.8 and 75% for each of the two graders, respectively; the specificity was 87.4% for both graders. CONCLUSIONS: This study supports the use of HE within a disc diameter of the center of the macula in nonstereo digital images for CSME detection in a screening setting.

Management of diabetic Macular oedema [abstract]

Diabetic Macular odema, defined as retinal thickening within a one disc diameter of the centre of the macular, is present in about 10 percent of all patients with diabetes mellitus, and is one of the major potential threats to vision from diabetic retinopathy. The odema may be focal, with leakage primarily from retinal capillary microaneurysms and often associated with hard exudate rings, or diffuse, with wide spread leakage from diffusely dialated capillaries, typically with a cystoid pattern of odema. The importance of recognizing retinal thickening as the diagnostic hallmark of macular odema will be emphasized, and examination techniques to detect retinal thickening will be reviewed. The laser treatment guidelines for clinically significant macular odema recommended by the Early Treatment Diabetic Retinopathy Study (ETDRS), and the preferred methods of administering that treatment, will be described. Options for management of persistent macular odema if the initial laser treatment fails will be discussed, including the use of diamox and others diuretics in the management of selected cases. (AU)