title: Retinal vessel diameter changes induced by transient high perfusion pressure.
abstract: OBJECTIVE
  To investigate the effects of transient high perfusion pressure on the retinal vessel diameter and retinal ganglion cells.
  
  
  METHODS
  The animals were divided into four groups according to different infusion pressure and infusion time (60 mm Hg-3min, 60 mm Hg-5min, 100 mm Hg-3min, 100 mm Hg-5min). Each group consisted of six rabbits. The left eye was used as the experimental eye and the right as a control. Retinal vascular diameters were evaluated before, during infusion, immediately after infusion, 5min, 10min and 30min after infusion based on the fundus photographs. Blood pressure was monitored during infusion. The eyes were removed after 24h. Damage to retinal ganglion cell (RGC) was analyzed by histology.
  
  
  RESULTS
  Retina became whiten and papilla optic was pale during perfusion. Measurements showed signiﬁcant decrease in retinal artery and vein diameter during perfusion in all of the four groups at the proximal of the edge of the optic disc. The changes were significant in the 100 mm Hg-3min group and 100 mm Hg-5min group compared with 60 mm Hg-3min group (P1=0.025, P2=0.000). The diameters in all the groups recovered completely after 30min of reperfusion. The number of RGC showed no signiﬁcant changes at the IOP in 100 mm Hg with 5min compared with contralateral untreated eye (P>0.05).
  
  
  CONCLUSIONS
  Transient fluctuations during infusion lead to temporal changes of retinal vessels, which could affect the retinal blood circulation. The RGCs were not affected by this transient fluctuation. Further studies are necessary to evaluate the effect of pressure during real-time phacoemusification on retinal blood circulation.
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China ; Affiliated Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China.
authors.forename: Yin-Ying
authors.initials: YY
authors.lastname: Zhao
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China ; Affiliated Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China.
authors.forename: Ping-Jun
authors.initials: PJ
authors.lastname: Chang
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China ; Affiliated Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Yu
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China ; Affiliated Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China.
authors.forename: Yun-E
authors.initials: YE
authors.lastname: Zhao
keywords: animals; ocular perfusion pressure; retinal ganglion cells; retinal ischemia