title: Acute conformational changes in the optic nerve head with rapid intraocular pressure elevation: implications for LASIK surgery.
abstract: OBJECTIVE
  To investigate the effects of acute intraocular pressure (IOP) elevation on optic disc morphology.
  
  
  METHODS
  Ophthalmodynamometry was used to increase the IOP of normal, healthy eyes. Confocal scanning laser ophthalmoscopy of the optic nerve head using the Heidelberg Retinal Tomograph II (Heidelberg GmbH, Heidelberg, Germany) and IOP measurements were obtained before, during, and after IOP elevation.
  
  
  RESULTS
  Sixteen eyes of 16 normal volunteers (mean age, 32.8 +/- 11.9 years) were enrolled. Rim area, rim volume, cup area, cup volume, cup-to-disc ratio, mean cup depth, maximum cup depth, mean retinal nerve fiber layer (RNFL) thickness, and RNFL cross-sectional area showed significant changes during IOP elevation (all P < .05, paired t test). All measured parameters returned to their original values after pressure resolution (all P > .2) except mean RNFL thickness (P = .03).
  
  
  CONCLUSIONS
  Transient elevation of IOP results in measurable alterations in optic nerve head topography.
authors.affiliation: Department of Ophthalmology, The New York Eye and Ear Infirmary, New York 10003, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Piette
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Liebmann
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Rabia
authors.initials: R
authors.lastname: Gürses-Ozden
authors.forename: Douglas
authors.initials: D
authors.lastname: Buxton
authors.forename: Robert
authors.initials: R
authors.lastname: Ritch
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D020731:Keratomileusis, Laser In Situ; D008297:Male; D018613:Microscopy, Confocal; D009412:Nerve Fibers / Q000473:pathology; D009887:Ophthalmoscopy; D009898:Optic Disk / Q000473:pathology*; D012016:Reference Values; D012160:Retina / Q000473:pathology