Abstract
Purpose: :
In patients with glaucoma, optic disc hemorrhage (DH) has been reported to be associated with localized retinal nerve fiber layer (RNFL) defects. We used spectral domain optical coherence tomography (SD-OCT) RNFL deviation maps to evaluate location and thickness of defects and their association with optic disc hemorrhage in patients with glaucoma.
Methods: :
Patients with the fundus photographs demonstrating DH who were also imaged with SD-OCT (Cirrus, Carl Zeiss Meditec, Inc., Dublin, CA) were included in this retrospective cross-sectional study. Fundus photos were evaluated by a reviewer for location of DH. RNFL was measured using SD-OCT reconstructed 360 degree circle scans for average thickness and thickness at site of DH. Fundus photos were magnified, aligned and compared with SD-OCT deviation maps to determine the location of DH in relation to RNFL defects. Average RNFL thickness for each eye was compared to RNFL thickness at the site of the DH using Wilcoxon matched pairs test.
Results: :
12/17 eyes (70.6%) had DH at the leading or temporal edge of the RNFL defect, while 4/17 eyes (23.5%) had DH in an area of normal RNFL thickness and 1/17 (5.9%) had DH within the center of the RNFL wedge defect. 0/18 eyes had DH at the lagging or nasal edge of the RNFL defect. DH was located in the inferior quadrant in 9/17 eyes (52.9%), temporal quadrant in 5/17 eyes (29.4%), and superior quadrant in 3/17 eyes (17.6%). The average RNFL thickness for eyes in this study was 74.6 microns (+/-12.9 SD), the average RNFL thickness at the site of disc hemorrhage was 58.8 microns (+/-25.2 SD). The average thickness of the RNFL at the site of DH was 15.8 microns (+/- 23.5) thinner than the average total RNFL thickness (P=0.01).
Conclusions: :
SD-OCT enables evaluation of RNFL defects by location. The RNFL deviation map allows comparison of RNFL defects imaged on SD-OCT to the location of DH seen on fundus photography. In eyes of patients with glaucoma and disc hemorrhage, the most common location of DH was in the inferior quadrant and at the leading edge of the RNFL defect. In addition, the RNFL measurements at the site of the DH were significantly thinner than the average RNFL thickness for the same eye.
Keywords: nerve fiber layer • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • optic disc