title: Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation.
abstract: OBJECTIVE
  To assess the quantitative and morphological changes of the macula in response to macular grid laser for diabetic macular oedema (DMO) using optical coherence tomography (OCT).
  
  
  METHODS
  Cirrus OCT macular cube scans of 30 eyes of 25 patients were retrospectively analysed before and 4 months after macular grid laser for diffuse DMO. The oedema was quantified and response evaluated in the nine early-treatment diabetic retinopathy study (ETDRS) zones of the macula. Post-laser OCT changes were compared with the baseline features, including morphology patterns, changes in both logarithmic transformed (logOCT) and standardised average macular thickness (AMT), total macular volume, number of parafoveal quadrants involved, and the presence of intact 3rd hyper-reflective band (HRB).
  
  
  RESULTS
  The rate of change of retinal thickness in response to laser was maximum in the central (8.17%) and perifoveal inferior quadrants (0.04%). Diffuse retinal thickening on OCT responded best to treatment. The AMT of 300-350 μm had the worst response (+0.94%). Eyes with less than four quadrants of oedema showed good response. Disrupted HRB was associated with poor visual gain (-0.33 ETDRS letters).
  
  
  CONCLUSIONS
  The topographic location of oedema on the retinal map and the morphological patterns of the oedema on OCT are useful predictors of treatment response in diffuse DMO.
authors.affiliation: Laser and Retinal Research Unit, King's College Hospital, London, UK.
authors.forename: R
authors.initials: R
authors.lastname: Vemala
authors.forename: S
authors.initials: S
authors.lastname: Koshy
authors.forename: S
authors.initials: S
authors.lastname: Sivaprasad
mesh_terms: D000328:Adult; D000368:Aged; D003930:Diabetic Retinopathy / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D017075:Laser Coagulation / Q000379:methods; D008269:Macular Edema / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000473:pathology / Q000528:radiation effects* / Q000601:surgery; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence / Q000379:methods; D014792:Visual Acuity / Q000502:physiology