title: Effects of change in intraocular pressure on axial eye length and lens position.
abstract: OBJECTIVE
  To quantify the biometric changes of ocular dimensions with mechanical elevation of intraocular pressure (IOP) in vivo, to get a better understanding of the elastic properties of the human ocular structures that may play a role in the pathogenesis of various diseases such as myopia or glaucoma.
  
  
  METHODS
  Changes in IOP were induced by a suction cup in 18 eyes under cycloplegia. Axial eye length (AEL) and anterior chamber depth (ACD) were measured with non-invasive laser interferometry during elevation of the IOP 10 and 20 mmHg over baseline values and after a 10-min resting period.
  
  
  RESULTS
  IOP elevation of 10 and 20 mmHg respectively caused a significant increase of AEL of 23 mum (95% confidence interval: 14-34 microm) and 39 microm (confidence interval (CI): 28-51 microm). After mechanical oculopression, which resulted in an IOP reduction of -5.1 mmHg (CI: -6.3 to -4.0 mmHg) vsbaseline, a significant shortening of -7 microm (CI: -13 to 0 microm) was observed. The change in AEL correlated with the change in IOP (r=0.66, P=0.005). Furthermore, a significant increase in ACD of 30 microm (CI: 24-36 microm) was detected with IOP reduction after oculopression, but no change was seen during IOP elevation.
  
  
  CONCLUSIONS
  Biometric changes of the human eye as a response to IOP changes were assessed in vivo. The correlation between change in AEL and IOP found emphasizes the need of in vivoocular rigidity measurements in the human eye.
authors.affiliation: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. christian.leydolt@meduniwien.ac.at
authors.forename: C
authors.initials: C
authors.lastname: Leydolt
authors.forename: O
authors.initials: O
authors.lastname: Findl
authors.forename: W
authors.initials: W
authors.lastname: Drexler
mesh_terms: D000328:Adult; D000867:Anterior Chamber / Q000033:anatomy & histology; D001699:Biometry; D005123:Eye / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D007908:Lens, Crystalline / Q000033:anatomy & histology; D008297:Male; D009216:Myopia / Q000503:physiopathology; D014065:Tonometry, Ocular