title: Anatomic pattern of arteriovenous crossings in branch retinal vein occlusion.
abstract: OBJECTIVE
  To determine the relative position of the two vessels at the site of venous obstruction, as it facilitates Arteriovenous adventitial sheathotomy and to look for the associated diseases with branch retinal vein occlusion (BRVO) so as to create more awareness among the masses.
  
  
  METHODS
  It was a case series carried out at the Ophthalmology out-patient department of Ziauddin University Hospital Karachi, Pakistan, from April 2005 to March 2006. The diagnosis of BRVO was made on the clinical basis. The fundus was photographed for confirmation and record purpose. The relative anatomic position of artery and vein at the site of occlusion, and the quadrant of occlusion were recorded. The associated diseases with BRVO were also identified.
  
  
  RESULTS
  Seventy patients were enrolled in the study. Forty nine were males and twenty one were females. Mean age of the male group was 51.5 + 8 years Mean age of the female group was 49.4+ 8.5 years. In all, there were seventy-two eyes with branch retinal vein occlusion. In seven eyes the relevant position of the artery and vein could not be ascertained. In 63 eyes (96.9%) the artery was anterior to the vein, and in the remaining 2 eyes (3.1%) the vein was anterior to the artery. There was a greater number of superotemporal occlusions as compared to inferotemporal occlusions. Fifty seven (81.4%) cases had associated hypertension, two (2.85%) had diabetes, seven (10%) had diabetes and hypertension, and four (5.7%) had no associated diseases. Fellow eyes were compared with the vein occlusion sites and the vein occlusion eyes. The differences were statistically significant (p.001), with a greater prevalence of arterial over crossings in the affected eye.
  
  
  CONCLUSIONS
  The study shows that artery lies anterior to the vein in almost all cases of BRVO. The study shows that more hypertensives present with BRVO as compared with diabetics and diabetics cum hypertensives.
authors.affiliation: Department of Anatomy, Ziauddin University, Karachi.
authors.forename: Sadaf
authors.initials: S
authors.lastname: Hamid
authors.forename: Sajid Ali
authors.initials: SA
authors.lastname: Mirza
authors.forename: Ishrat
authors.initials: I
authors.lastname: Shokh
mesh_terms: D000328:Adult; D001163:Arteriovenous Anastomosis / Q000473:pathology*; D005260:Female; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D008875:Middle Aged; D012161:Retinal Artery / Q000473:pathology*; D012169:Retinal Vein / Q000473:pathology*; D012170:Retinal Vein Occlusion / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index