title: Improving Accuracy of Grading and Referral of Diabetic Macular Edema Using Location and Extent of Hard Exudates in Retinal Photography.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: School of Optometry, University of California, Berkeley, Berkeley, CA, USA Vision Science Graduate Group, University of California, Berkeley, Berkeley, CA, USA taras@berkeley.edu.
authors.forename: Taras V
authors.initials: TV
authors.lastname: Litvin
authors.affiliation: School of Optometry, University of California, Berkeley, Berkeley, CA, USA.
authors.forename: Camille R
authors.initials: CR
authors.lastname: Weissenberg
authors.affiliation: Los Angeles County Department of Health Services, Ophthalmology and Eye Health Programs, Los Angeles, CA, USA.
authors.forename: Lauren P
authors.initials: LP
authors.lastname: Daskivich
authors.affiliation: Optovue, Inc, Fremont, CA, USA.
authors.forename: Qienyuan
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: School of Optometry, University of California, Berkeley, Berkeley, CA, USA EyePACS, LLC, San Jose, CA, USA.
authors.forename: George H
authors.initials: GH
authors.lastname: Bresnick
authors.affiliation: School of Optometry, University of California, Berkeley, Berkeley, CA, USA Vision Science Graduate Group, University of California, Berkeley, Berkeley, CA, USA EyePACS, LLC, San Jose, CA, USA.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Cuadros
mesh_terms: D000328:Adult; D000368:Aged; D003930:Diabetic Retinopathy / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008269:Macular Edema / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: diabetic macular edema; hard exudates; optical coherence tomography; screening