title: Anterior Displacement of Lamina Cribrosa during Valsalva Maneuver in Young Healthy Eyes.
abstract: OBJECTIVE
  To investigate lamina cribrosa (LC) displacement during the Valsalva maneuver in young healthy eyes using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT).
  
  
  METHODS
  Forty-eight eyes of 48 young healthy volunteers (age range: 20-34 years) underwent intraocular pressure (IOP) measurement by Goldmann applanation tonometry as well as Cirrus HD-OCT scans before and during the Valsalva maneuver. The optic nerve head (ONH) parameters (average retinal nerve fiber layer thickness, rim area, disc area, average C/D ratio, vertical C/D ratio, cup volume), anterior LC depth (LCD), subfoveal and peripapillary choroidal thickness, and neural canal opening diameter were measured on compensated OCT and compared during Valsalva challenge. The subjects were asked to take a five-minute break after each Valsalva maneuver.
  
  
  RESULTS
  During the Valsalva maneuver, the IOP significantly increased, from 12.7 ± 3.0 mmHg to 16.0 ± 3.2 mmHg (P < 0.001), while the LCD sharply decreased, from 463.4 ± 118.8 μm to 427.3 ± 106.4 μm (P < 0.001). The subfoveal choroidal thickness (300.7 ± 90.6 vs. 309.6 ± 93.5 μm), peripapilllary choroidal thickness (152.2 ± 55.4 vs. 150.8 ± 49.3 μm), neural canal opening diameter (1651.8 ± 204.2 vs. 1651.0 ± 217.6 μm), and all of the ONH parameters did not change significantly (all P > 0.05).
  
  
  CONCLUSIONS
  The Valsalva maneuver induced anterior displacement of the LC, but did not alter the choroidal thickness or ONH morphology. The data describe the positional characteristics of the LC in response to the Valsalva maneuver in young healthy eyes.
authors.affiliation: Department of Ophthalmology, Armed Forces Busan Hospital, Busan, Korea.
authors.forename: Yong Woo
authors.initials: YW
authors.lastname: Kim
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.|Singapore Eye Research Institute, Singapore, Singapore.
authors.forename: Michael J A
authors.initials: MJ
authors.lastname: Girard
authors.affiliation: University of French Polynesia, Tahiti, French Polynesia.
authors.forename: Jean Martial
authors.initials: JM
authors.lastname: Mari
authors.affiliation: Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jin Wook
authors.initials: JW
authors.lastname: Jeoung
mesh_terms: D000328:Adult; D002829:Choroid / Q000473:pathology; D003710:Demography; D005123:Eye / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D009898:Optic Disk / Q000473:pathology; D012015:Reference Standards; D014636:Valsalva Maneuver; D055815:Young Adult