title: Identifying a clinically meaningful threshold for change in uveitic macular edema evaluated by optical coherence tomography.
abstract: OBJECTIVE
  To identify a clinically meaningful threshold for change in retinal thickness measured by optical coherence tomography for patients with uveitic macular edema using correlation with change in visual acuity.
  
  
  METHODS
  Cross-sectional and longitudinal study.
  
  
  METHODS
  One hundred twenty-eight eyes (101 individuals) with macular edema enrolled in the Multicenter Uveitis Steroid Treatment (MUST) trial. At enrollment and after 6 months of follow-up, retinal thickness was measured at the central subfield with time-domain optical coherence tomography and visual acuity was measured with logarithmic (Early Treatment Diabetic Retinopathy Study) visual acuity charts. Participants were classified as having macular edema if the retinal thickness was 260 μm or more.
  
  
  RESULTS
  A threshold for change in retinal center subfield thickness of 20% balanced the percentage of false positives and false negatives for predicting more than a 10-letter change in visual acuity with a sensitivity of 77% and a specificity of 75%. The results were similar for more than 5-letter changes and for 15-letter or more changes. Those with a 20% or more reduction in retinal thickness had a mean 11.0-letter improvement (95% confidence interval, 7.7 to 14.3) as compared with a -0.4-letter change (95% confidence interval, -4.1 to 3.3) in visual acuity for those without a 20% reduction (P < .01).
  
  
  CONCLUSIONS
  In addition to being above the level of measurement uncertainty, a 20% change in retinal thickness in patients with macular edema seems to be optimal for clinically important changes in visual acuity and may be considered as an outcome for clinical trials of treatments for uveitic macular edema.
authors.affiliation: Department of Epidemiology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA. esugar@jhsph.edu
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Sugar
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Jabs
authors.forename: Michael M
authors.initials: MM
authors.lastname: Altaweel
authors.forename: Sue
authors.initials: S
authors.lastname: Lightman
authors.forename: Nisha
authors.initials: N
authors.lastname: Acharya
authors.forename: Albert T
authors.initials: AT
authors.lastname: Vitale
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Thorne
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005189:False Positive Reactions; D005260:Female; D005446:Fluocinolone Acetonide / Q000008:administration & dosage; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D008137:Longitudinal Studies; D008269:Macular Edema / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D012680:Sensitivity and Specificity; D012684:Sensory Thresholds / Q000502:physiology; D041623:Tomography, Optical Coherence; D014605:Uveitis / Q000188:drug therapy / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*
chemical_list: D005938:Glucocorticoids; D005446:Fluocinolone Acetonide