title: 24-Hour variation of optical coherence tomography-measured retinal thickness in diabetic macular edema.
abstract: OBJECTIVE
  To investigate 24-hour variation in retinal thickness in patients with diabetic macular edema (DME) using optical coherence tomography (OCT).
  
  
  METHODS
  Fifty-three eyes of 53 diabetic patients with clinically significant macular edema and central subfield thickness (CST) >225 µm, 36 eyes of 36 healthy individuals (normal controls), and 22 eyes of 22 diabetic patients without macular pathology (diabetic controls) underwent 5 OCT measurements at 7 am, 10 am, 3 pm, 8 pm, and 1 am. Visual acuity, blood pressure, blood glucose, and body temperature were measured as well.
  
  
  RESULTS
  The CST (p<0.0005), total macular volume (p<0.0005), and visual acuity (p<0.0005) showed significant variation in patients. The CST (450 µm at 7 am) reached a minimum at 3 pm (absolute change of -49 µm, relative change of -17%) before increasing again. Thickening changes were higher in more thickened retinas (p<0.0005, p=0.024, absolute and relative change, respectively). Visual acuity was worse in the morning (0.38 logMAR) and improved to a maximum at 8 pm (0.30 logMAR) (p<0.0005). Blood pressure, blood glucose, and body temperature did not vary over time.
  
  
  CONCLUSIONS
  The 24-hour variation of retinal thickness is observed in a large proportion of patients with DME, with a decrease from morning to afternoon. Time of examination should be taken into account when managing such patients.
authors.affiliation: 1st Department of Ophthalmology, AHEPA University Hospital, Thessaloniki, Greece. skots2@yahoo.gr
authors.forename: Sokratis T
authors.initials: ST
authors.lastname: Kotsidis
authors.forename: Simeon S
authors.initials: SS
authors.lastname: Lake
authors.forename: Alexandros D
authors.initials: AD
authors.lastname: Alexandridis
authors.forename: Nikolaos G
authors.initials: NG
authors.lastname: Ziakas
authors.forename: Panagiotis K
authors.initials: PK
authors.lastname: Ekonomidis
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature; D002940:Circadian Rhythm / Q000502:physiology*; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008269:Macular Edema / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012160:Retina / Q000473:pathology*; D013997:Time Factors; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology
chemical_list: D001786:Blood Glucose