Effect of lowering intraocular pressure on optical coherence tomography measurement of peripapillary retinal nerve fiber layer thickness.
OBJECTIVE
To assess, with optical coherence tomography (OCT), any changes in peripapillary retinal nerve fiber layer (RNFL) thickness in glaucoma patients after reduction of intraocular pressure (IOP).


METHODS
Prospective observational case series.


METHODS
Twenty-one eyes of 21 glaucoma patients who underwent medical or surgical intervention to lower IOP.


METHODS
Patients with elevated IOP underwent fast peripapillary RNFL measurements with the Stratus OCT (model 3000, software version 4.04; Carl Zeiss Meditec, Dublin, CA) before and after the IOP was lowered by medical or surgical therapy.


METHODS
Changes in overall and quadrant RNFL thickness with respect to change in IOP.


RESULTS
The OCT scans were performed before intervention (range, 0-38 days before; mean+/-standard deviation [SD], 9.8+/-9.3 days) and after intervention (range, 32-74 days; mean+/-SD, 46.8+/-11.2 days) to measure peripapillary RNFL thickness. Mean IOP (mean+/-SD) decreased from 31.5+/-8.2 mmHg to 12.8+/-4.6 mmHg with the intervention (P<0.001). Twenty of 21 eyes had an IOP reduction of more than 30%. There was no significant change in the overall RNFL thickness associated with the lowering of IOP (mean+/-SD, 1.02+/-10.3 microm; P = 0.653). Quadrant analysis did not show a significant change in the RNFL thickness of any of the 4 quadrants (superior, -1.71+/-14.5 microm, P = 0.593; inferior, 2.38+/-16.8 microm, P = 0.523; temporal, 2.19+/-9.50 microm, P = 0.303; and nasal, 1.24+/-12.5 microm, P = 0.655). No relationship was found between any of the changes in OCT parameters or percent change in OCT parameters and the extent of IOP reduction, or whether IOP was lowered medically or surgically, with or without adjusting for preintervention OCT measurements as an indication of disease severity (P values ranged from 0.331 to 0.985).


CONCLUSIONS
No significant change in the RNFL thickness was associated with the lowering of IOP by medical or surgical therapy, as measured by OCT.
Chang
Peter T
PT
Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, USA. ptchang@bcm.edu
Sekhon
Navneet
N
Budenz
Donald L
DL
Feuer
William J
WJ
Park
Paul W
PW
Anderson
Douglas R
DR
D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D017889:Exfoliation Syndrome / Q000150:complications; D005260:Female; D020327:Glaucoma Drainage Implants; D005902:Glaucoma, Open-Angle / Q000188:drug therapy / Q000601:surgery / Q000628:therapy*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000188:drug therapy / Q000601:surgery / Q000628:therapy*; D011446:Prospective Studies; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014130:Trabeculectomy
D000959:Antihypertensive Agents