title: Diurnal variation of the incidence of symptomatic branch retinal vein occlusion.
abstract: OBJECTIVE
  To investigate the diurnal variation that is related to the incidence of branch retinal vein occlusion (BRVO).
  
  
  METHODS
  This is a cross-sectional study. 72 consecutive patients who were newly diagnosed with BRVO were precisely questioned about the time of their symptom onset. The clinical history, systemic illnesses, ocular findings, and body mass index were obtained for each patient.
  
  
  RESULTS
  Analysis of the diurnal variation of symptom onset showed a distribution with the peak in the period from 6 a.m. to noon compared with all the other time periods (p < 0.001). Multivariate analysis showed that involvement of the superior retina was the only factor that influenced the onset time of BRVO.
  
  
  CONCLUSIONS
  Patients with symptomatic BRVO frequently noted their visual deterioration in the morning, which is the same as the other types of ocular and systemic vascular disease. Our results may be helpful for understanding the pathophysiology of BRVO. Our findings require conformation and further studies on this subject are certainly warranted.
authors.affiliation: Department of Ophthalmology, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Sungbuk-gu, Seoul 136-705, Korea. ojr4991@yahoo.co.kr
authors.forename: Jaeryung
authors.initials: J
authors.lastname: Oh
authors.forename: In Kyung
authors.initials: IK
authors.lastname: Oh
authors.forename: Kuhl
authors.initials: K
authors.lastname: Huh
mesh_terms: D000328:Adult; D000368:Aged; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012170:Retinal Vein Occlusion / Q000209:etiology / Q000503:physiopathology*; D013997:Time Factors; D014786:Vision Disorders / Q000209:etiology / Q000503:physiopathology*