title: Intraocular pressure changes following 20G pars-plana vitrectomy.
abstract: OBJECTIVE
  To observe the excursions of short-term intraocular pressure (IOP) after 20-G pars-plana vitrectomy (ppV).
  
  
  METHODS
  In a prospective study, 851 patients (age: mean 63 ± 15 years) underwent unilateral ppV for various vitreoretinal diseases using different endotamponades [Balanced Salt Solution (BSS) 33.1%, Air 7.2%, SF(6) 33.6%, silicon oil 5000 cst 26.1%]. Intraocular pressure was measured in all patients before and at 3, 6, 24 and 48 hr after surgery. Survival analysis was performed to determine the cumulative hazard of IOP changes depending on endotamponade and time point after ppV (Log-Rang - Mantel Cox; p < 0.0001).
  
  
  RESULTS
  At baseline, IOP ranged from 0 to 50 mmHg (mean IOP: 15.3 ± 5.3 mmHg). Mean IOP after surgery revealed a slight elevation (3 hr: 16.5 ± 11.0 mmHg; 6 hr 16.9 ± 9.8 mmHg; 24 hr 19.7 ± 8.0 mmHg; 48 hr 17.3 ± 6.2 mmHg; range: 0-64 mmHg). Silicon oil filling revealed highest mean values at already 3 hr after surgery (21.8 mmHg). Also, BSS filling showed a peak after 3 hr; however, mean values were lower. Equivalent high IOP values as for silicon oil tamponade were found for gas filling; however, maximal peak was reached after 24 hr but not after 3 hr post-treatment. The cumulative hazard in all patients to reach IOP ≥ 30 mmHg after 24 hr was 23.9%; (IOP ≥ 40 mmHg = 8.2%). Herein, oil filling revealed highest risk at all time points after surgery. The risk of suffering from IOP < 5 mmHg lasting longer than 6 hr was only 1.2% after 20 G vitrectomy.
  
  
  CONCLUSIONS
  Intraocular pressure measurements after ppV are important to prevent unintentional high IOP, especially within the early phase (3 hr post-treatment) in eyes with silicon oil filling. Gas filling leads to prolonged IOP increase (24 hr post-treatment). Long-lasting hypotony (≥ 6 hr) is very rare after 20G vitrectomy.
authors.affiliation: Department of Ophthalmology, Inselspital, University of Bern, Freiburgstrasse, Bern, Switzerland.
authors.forename: Carsten
authors.initials: C
authors.lastname: Framme
authors.forename: Susanne
authors.initials: S
authors.lastname: Klotz
authors.forename: Ute E K
authors.initials: UE
authors.lastname: Wolf-Schnurrbusch
authors.forename: Peter
authors.initials: P
authors.lastname: Wiedemann
authors.forename: Sebastian
authors.initials: S
authors.lastname: Wolf
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000388:Air; D058450:Endotamponade; D005128:Eye Diseases / Q000601:surgery; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D009798:Ocular Hypertension / Q000503:physiopathology; D009901:Optic Nerve Diseases / Q000503:physiopathology / Q000517:prevention & control; D011183:Postoperative Complications; D011446:Prospective Studies; D012164:Retinal Diseases / Q000601:surgery; D012827:Silicone Oils / Q000008:administration & dosage; D013459:Sulfur Hexafluoride / Q000008:administration & dosage; D014065:Tonometry, Ocular; D014821:Vitrectomy; D014822:Vitreous Body / Q000601:surgery; D055815:Young Adult
chemical_list: D012827:Silicone Oils; D013459:Sulfur Hexafluoride