Abstract
Purpose :
Bruch Membrane’s Opening (BMO), the termination of Bruch’s membrane measured by spectral-domain optical coherence tomography (SD-OCT) is an accurate anatomic boundary of the neuro retinal rim tissue. Using BMO-Minimum Rim Width (BMO-MRW), the shortest distance from the BMO to the inner limiting membrane (ILM) enables clinicians to have high diagnostic performance for open-angle glaucoma. We prospectively investigate alterations of the optic nerve head (ONH) structure using SD-OCT derived BMO-MRW, RNFLT in eyes of open angle glaucoma as well as to investigate the relationship between changes in BMO-MRW and those in the amount of prelaminar tissue displacement after trabeculectomy (TLE).
Methods :
A total of 31 eyes of 31 patients which achieved a 20% or more IOP reduction at three months after TLE were included (Age: 68.7±11.9). We measured MRW, RNFLT and BMO Area using SD-OCT before surgery and 3 months postoperatively. BMO and RNFLT were measured in seven areas of ONH (Global, Temporal, Temporal Superior, Temporal Inferior, Nasal, Nasal Superior, Nasal Inferior). Cup size was also evaluated in 2 scans, passing through temporal-superior to nasal –inferior and temporal-inferior to nasal-superior of the ONH(Figure 1). For measuring cup size, we made linear lines from the two ends of the BMO to the corresponding visible edges of the anterior laminar surface and measured the area using Image J. Alterations of MRW, RNFLT, BMO Area and cup size were analyzed by the Wilcoxon's signed rank test. Correlations between MRW, RNFLT, cup size and the reduction of IOP were analyzed by Spearman's rank correlation coefficient.
Results :
MRW increased significantly in Global, Temporal Superior and Nasal region (p<0.05), RNFLT didn’t increase in any region, and BMO Area significantly decreased (p=0.022), Cup size decreased significantly in the 2 scans and the mean value (p<0.05). MRW increase and IOP reduction correlated significantly in Global, Temporal and Nasal Inferior region (p=0.045, p=0.002, p=0.041). Cup size reduction and IOP reduction rate correlated significantly in temporal-inferior to nasal-superior line and the mean value of two lines (p=0.010, p=0.037).
Conclusions :
MRW increased and its increase correlated with IOP reduction.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.