Optical coherence tomography assessment of retinal nerve fiber layer thickness changes after glaucoma surgery☆
Presented in part at the annual meeting of the American Academy of Ophthalmology, Orlando, Florida, October 2002.
Received 17 July 2002; accepted 16 January 2003.
Abstract
Purpose
To assess changes in retinal nerve fiber layer (NFL) thickness in glaucoma patients after filtration surgery by using optical coherence tomography (OCT).
Design
Retrospective observational case series.
Participants
Thirty-eight eyes of 31 glaucoma patients who underwent trabeculectomy or a combined procedure of cataract extraction and trabeculectomy were evaluated retrospectively.
Methods
Eyes were imaged with OCT before surgery (1 week to 6 months before surgery; mean ± standard deviation [SD], 71.3 ± 61.2 days) and after surgery (6–12 months after surgery; 247.2 ± 63.5 days) to measure peripapillary NFL thickness.
Main outcome measures
Changes in mean and segmental NFL thickness with respect to age, postoperative change in intraocular pressure (IOP), preoperative visual field test global indices, and change in visual field global indices.
Results
A significant increase in the overall mean NFL thickness was present after surgery (P < 0.0001). Segmental analysis found a significant increase in NFL thickness in the nasal, superior, and temporal quadrants. IOP decreased after surgery from 22.0 ± 6.4 mmHg to 11.4 ± 4.7 mmHg (mean ± SD). Twenty-eight (73.7%) of 38 eyes had an IOP reduction >30%. The mean NFL thickness increase (0.5-μm/mmHg decrease of IOP) was significantly correlated with the IOP reduction (r = −0.41; P = 0.03). No correlation was found between NFL thickness changes and age, preoperative visual field global indices, or change in visual field global indices.
Conclusions
A significant increase of the mean NFL thickness, which was related to IOP reduction, was detected after glaucoma filtration surgery.
1New England Eye Center, Tufts University School of Medicine, Boston, Massachusetts, USA
2Biostatistics Research Center, Tufts-New England Medical Center, Boston, Massachusetts, USA
3Department of Electrical Engineering and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
Reprint requests to Joel S. Schuman, MD, UPMC Eye Center, University of Pittsburgh School of Medicine, 203 Lothrop Street, Pittsburgh, PA 15213, USA.
Supported in part by the National Institutes of Health (grant nos.: 1-RO1 EY 13178-02 [JSS] and 2-RO1 EY 11289-15 [J. G.J. G. Fujimoto, PhD]), Bethesda, MD, and by Carl Zeiss Meditech research grant support (JSS), Dublin, CA.
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