title: Correlation Between Visual Function and Photoreceptor Integrity in Diabetic Macular Edema: Spectral-Domain Optical Coherence Tomography.
abstract: OBJECTIVE
  To evaluate the relationship between visual function and (i) microstructural changes in the fovea of the inner segment-outer segment junction (IS/OS) and (ii) external limiting membrane (ELM) in diabetic macular edema (DME).
  
  
  METHODS
  We conducted a retrospective, observational, cross-sectional study of 40 DME patients (61 eyes), all of whom had been treated at Shanghai First People's Hospital. Patients were divided into groups based on integrity of the IS/OS or ELM: IS/OS (+, ± and -) and ELM (+, ± and -). We performed best-corrected visual acuity (BCVA), MP1 microperimetry and spectral-domain optical coherence tomography (SD-OCT) on all patients. Several variables, including IS/OS and ELM integrity, central macular thickness (CMT) and central macular volume (CMV), were evaluated by two observers, each masked to patients' BCVA. Main outcome measures included determination of the association of visual function with SD-OCT results.
  
  
  RESULTS
  Significant differences were found between IS/OS (+), IS/OS (±) and IS/OS (-) groups in BCVA (66.88 ± 7.89, 51.60 ± 9.39, 32.64 ± 17.93 letters, p < 0.001); macular sensitivity (MS; 8.21 ± 2.91, 3.55 ± 2.75, 2.72 ± 1.86 dB, p < 0.001); fixation stability within 2° (82.09 ± 12.76, 66.43 ± 29.54, 33.73 ± 29.51%, p < 0.001); and % central fixation (74.87 ± 16.88, 61.39 ± 31.38, 31.64 ± 31.89%, p < 0.001); but no differences were found for CMT (p = 0.069) or CMV (p = 0.069). Results were similar for ELM groups. There were significant differences between ELM (+), ELM (±) and ELM (-) groups in BCVA (64.16 ± 9.49, 50.44 ± 9.83, 32.73 ± 17.98 letters, p < 0.001); MS (7.54 ± 3.22, 3.38 ± 2.38, 2.20 ± 1.72 dB, p < 0.001); fixation stability within 2° (81.48 ± 15.26, 61.12 ± 31.63, 35.00 ± 29.07%, p < 0.001); and % central fixation (75.90 ± 17.33, 55.88 ± 30.94, 30.09 ± 33.00%, p < 0.001); but not for CMT (p = 0.216) or CMV (p = 0.202). There was a strong correlation (r = 0.881, p < 0.001) between ELM and IS/OS integrity for the same patient. Categories of IS/OS showed more severe changes than did those of ELM.
  
  
  CONCLUSIONS
  Both IS/OS and ELM integrity correlated positively with visual function in DME patients. Further studies are needed to confirm and validate this relationship.
authors.affiliation: a Department of Ophthalmology , Shanghai First People's Hospital affiliated with Shanghai Jiao Tong University , Shanghai , People's Republic of China and.|b Shanghai Jiao Tong University School of Medicine , Shanghai , People's Republic of China.
authors.forename: Yinchen
authors.initials: Y
authors.lastname: Shen
authors.affiliation: a Department of Ophthalmology , Shanghai First People's Hospital affiliated with Shanghai Jiao Tong University , Shanghai , People's Republic of China and.
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.affiliation: a Department of Ophthalmology , Shanghai First People's Hospital affiliated with Shanghai Jiao Tong University , Shanghai , People's Republic of China and.
authors.forename: Xun
authors.initials: X
authors.lastname: Xu
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008269:Macular Edema / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020419:Photoreceptor Cells, Vertebrate / Q000473:pathology*; D012160:Retina / Q000502:physiology*; D055211:Retinal Photoreceptor Cell Inner Segment / Q000502:physiology; D055214:Retinal Photoreceptor Cell Outer Segment / Q000502:physiology; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology*; D058609:Visual Field Tests
keywords: Diabetic macular edema; external limiting membrane; inner segment-outer segment junction; integrity of photoreceptor layer; microperimetry; optical coherence tomography