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Abstract #46310 Published in IGR 13-2
Quantification of change in axonal birefringence following surgical reduction in intraocular pressure
Sehi M; Grewal DS; Zhu H; Feuer WJ; Greenfield DSOphthalmic surgery, lasers & imaging : the official journal of the International Society for Imaging in the Eye 2011; 42: 45-52
the purpose of this study was to examine the hypothesis that retinal nerve fiber layer (RNFL) birefringence increases following surgical reduction of intraocular pressure (IOP). twenty-six glaucomatous eyes requiring trabeculectomy or drainage implant were enrolled. Optical coherence tomography (OCT), scanning laser polarimetry (SLP), and IOP measurements were performed preoperatively and 3 months postoperatively. The OCT and SLP images were aligned using a new algorithm that aligns the vessels in an OCT image to those in the corresponding SLP reflectance image. The SLP retardance values at the location of the OCT scan circle were then extracted using the OCT scan circle position inferred by the algorithm. Sixty-four corresponding RNFL segments were extracted from SLP and OCT to calculate RNFL birefringence. A significant birefringence change was defined as 1.96 times the weighted test-retest standard deviation in four contiguous segments. preoperative IOP (19.3 (plus or minus) 6.1 mm Hg) was significantly (P < .001) lower than postoperative IOP (10.4 (plus or minus) 3.7 mm Hg). Average birefringence magnitude did not change (P = .19) postoperatively. Localized birefringence magnitude increased significantly in 6 (23%) eyes and decreased significantly in 7 (27%) eyes. in this cohort, variable changes in localized birefringence were observed following surgical reduction of IOP.
M. Sehi. Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 7101 Fairway Drive, Palm Beach, Gardens, FL 33418, USA. Email: msehi@med.miami.edu
Classification:
6.9.1.2 Confocal Scanning Laser Polarimetry (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.1 Laser scanning)
6.9.2.2 Posterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
