title: Association of retinal sensitivity to integrity of photoreceptor inner/outer segment junction in patients with diabetic macular edema.
abstract: OBJECTIVE
  To evaluate the relationship between retinal sensitivity and the photoreceptor inner segment/outer segment (IS/OS) layer status in patients with diabetic macular edema (DME).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Twenty-five adult patients (37 eyes) diagnosed with DME and managed at the Wilmer Eye Institute, Johns Hopkins University (Baltimore, MD).
  
  
  METHODS
  We obtained simultaneous fundus microperimetry (MP) and optical coherence tomography (OCT) of patients with DME using a combined MP/OCT system. The device recorded retinal sensitivity and retinal thickness on a 3-dimensional tomography map, and we performed a point-by-point analysis of the IS/OS layer integrity at every MP point. We also reviewed OCT scans to determine the type of DME, cystoid macular edema, or diffuse macular edema (absence of any cysts). In addition, fixation stability and fixation location were analyzed.
  
  
  METHODS
  Retinal point sensitivity measured by MP.
  
  
  RESULTS
  Twenty-five patients (37 eyes: 29 male and 8 female; mean age, 64.16 years) with DME were enrolled. Fixation was centric in 30 eyes (81%), paracentric in 3 eyes (8%), and eccentric in 4 eyes (11%). Twenty-seven eyes had cystoid macular edema, and 10 eyes had diffuse macular edema. Mean central subfield thickness was 325 μm. We analyzed a total of 1036 individual MP points. Mean point sensitivity was 10.51 dB. A total of 793 points (76.5%) had IS/OS layer present, and 243 points (23.5%) had IS/OS layer disrupted. A mixed linear model, constructed to adjust for potential confounders and account for dependence between retinal points, revealed that the absence of the IS/OS junction was significantly associated with a 3.28-dB decrease in retinal point sensitivity (P<0.001).
  
  
  CONCLUSIONS
  This novel index study demonstrates that disruption of the IS/OS junction is correlated with a significant decrease in point sensitivity in eyes with DME. Further studies are indicated to confirm and validate this relationship.
  
  
  BACKGROUND
  Proprietary or commercial disclosure may be found after the references.
authors.affiliation: Retinal Imaging Research and Reading Center, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Jithin
authors.initials: J
authors.lastname: Yohannan
authors.forename: Millena
authors.initials: M
authors.lastname: Bittencourt
authors.forename: Yasir Jamal
authors.initials: YJ
authors.lastname: Sepah
authors.forename: Elham
authors.initials: E
authors.lastname: Hatef
authors.forename: Raafay
authors.initials: R
authors.lastname: Sophie
authors.forename: Ahmadreza
authors.initials: A
authors.lastname: Moradi
authors.forename: Hongting
authors.initials: H
authors.lastname: Liu
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ibrahim
authors.forename: Diana V
authors.initials: DV
authors.lastname: Do
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Coulantuoni
authors.forename: Quan Dong
authors.initials: QD
authors.lastname: Nguyen
mesh_terms: D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D005451:Fluorescein Angiography; D006801:Humans; D021621:Imaging, Three-Dimensional; D008269:Macular Edema / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000503:physiopathology*; D055211:Retinal Photoreceptor Cell Inner Segment / Q000473:pathology*; D055214:Retinal Photoreceptor Cell Outer Segment / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology