Acute conformational changes in the optic nerve head with rapid intraocular pressure elevation: implications for LASIK surgery.
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.
Piette
Scott
S
Department of Ophthalmology, The New York Eye and Ear Infirmary, New York 10003, USA.
Liebmann
Jeffrey M
JM
Ishikawa
Hiroshi
H
Gürses-Ozden
Rabia
R
Buxton
Douglas
D
Ritch
Robert
R
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