title: Intraocular pressure fluctuation during microincision vitrectomy with constellation vision system.
abstract: OBJECTIVE
  To investigate intraocular pressure (IOP) fluctuation during various vitrectomy maneuvers using the vitrectomy system (Alcon Constellation Vision System).
  
  
  METHODS
  An experimental study as laboratory investigation.
  
  
  METHODS
  In porcine eyes, 23- and 25-gauge vitrectomy was performed, and IOP fluctuations were evaluated in vitreous cutting mode, in aspiration mode, and during scleral compression. The measurements were performed with the IOP control setting turned on or off.
  
  
  RESULTS
  Using the 23-gauge system with the IOP control setting turned on, IOP decreased from 30 to 23.7 mm Hg after starting vitreous cutting, and then returned to 30 mm Hg in 2.6 seconds. When the IOP control setting was turned off, IOP decreased to 19.1 mm Hg in 0.9 seconds, and remained at that pressure. Under aspiration at 650 mm Hg without cutting, IOP showed a sharp depression from 30 to 12.2 mm Hg, and then returned to 30.6 mm Hg in 2.6 seconds with the IOP control setting turned on. When the IOP control setting was turned off, IOP decreased to 2.2 mm Hg in 9.7 seconds, and did not recover. When the sclera was compressed without aspiration, IOP rapidly increased to 70-100 mm Hg, and then slowly decreased to 30 mm Hg in 3.5-4.0 seconds, with or without the IOP control system. Similar data were obtained with 25-gauge vitrectomy.
  
  
  CONCLUSIONS
  The IOP control system can attenuate IOP fluctuations during vitrectomy maneuvers. There was no significant difference in IOP fluctuations between 23- and 25-gauge systems.
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Yoshimi
authors: Y
authors: Sugiura
authors: Fumiki
authors: F
authors: Okamoto
authors: Yoshifumi
authors: Y
authors: Okamoto
authors: Takahiro
authors: T
authors: Hiraoka
authors: Tetsuro
authors: T
authors: Oshika
mesh_terms: D000818:Animals; D004322:Drainage; D007429:Intraocular Pressure / Q000502:physiology*; D007432:Intraoperative Period; D008866:Microsurgery / Q000379:methods*; D023421:Models, Animal; D016343:Monitoring, Intraoperative; D013552:Swine; D014821:Vitrectomy / Q000295:instrumentation / Q000379:methods*; D014822:Vitreous Body / Q000601:surgery*