title: Can we trust intraocular pressure measurements in eyes with intracameral air?
abstract: OBJECTIVE
  To evaluate the effect of intracameral air on intraocular pressure (IOP) measurements using Goldmann applanation tonometry (GAT) and applanation resonance tonometry (ART) in an in-vitro porcine eye model.
  
  
  METHODS
  IOP was measured on thirteen freshly enucleated eyes at three reference pressures: 20, 30, and 40 mmHg. Six measurements/method were performed in a standardized order with GAT and ART respectively. Air was injected intracamerally in the same manner as during Descemet's stripping endothelial keratoplasty (DSEK) and Descemet's membrane endothelial keratoplasty (DMEK), and the measurements were repeated.
  
  
  RESULTS
  Measured IOP increased significantly for both tonometry methods after air injection: 0.7 ± 2.1 mmHg for GAT and 10.6 ± 4.9 mmHg for ART. This difference was significant at each reference pressure for ART but not for GAT.
  
  
  CONCLUSIONS
  Although slightly affected, this study suggests that we can trust GAT IOP-measurements in eyes with intracameral air, such as after DSEK/DMEK operations. Ultrasound-based methods such as ART should not be used.
authors.affiliation: Department of Clinical Science, Ophthalmology, Umeå University, Umeå, SE-901 85, Sweden, gauti.johannesson@ophthal.umu.se.
authors.forename: Gauti
authors.initials: G
authors.lastname: Jóhannesson
authors.forename: Christina
authors.initials: C
authors.lastname: Lindén
authors.forename: Anders
authors.initials: A
authors.lastname: Eklund
authors.forename: Anders
authors.initials: A
authors.lastname: Behndig
authors.forename: Per
authors.initials: P
authors.lastname: Hallberg
mesh_terms: D000388:Air; D000818:Animals; D000867:Anterior Chamber / Q000502:physiology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D023421:Models, Animal; D015203:Reproducibility of Results; D013552:Swine; D014065:Tonometry, Ocular / Q000295:instrumentation*