Abstract
Purpose: :
To measure retinal thickness in the papillomacular bundle in glaucoma patients compared to healthy controls using Bruch’s membrane opening as a fixed reference point.
Methods: :
Eighteen subjects (nine patients with open angle glaucoma and nine healthy controls) were investigated using high resolution spectral domain optical coherence tomography approved for routine clinical use (HRA+OCT, Heidelberg Engineering, Germany). Infrared reflectance images and OCT scans (40’000 A-Scans/sec) were acquired simultaneously and 20 consecutive B-Scans were automatically averaged to improve signal to noise ratio. An online tracking system compensated for eye movements during data acquisition. Averaged horizontal B-Scans were used for further evaluation and retinal thickness was measured at the temporal optic disc border where the signal of Bruch’s membrane ends.
Results: :
Retinal thickness in the papillomacular bundle was 178±51 µm in glaucoma and 281±34 µm in the control group (p<0.001, Mann-Whitney-U test). An association between retinal thickness in the papillomacular bundle and morphologic glaucomatous damage was found (r=-0.765; p=0.001; Spearman-Rho test).
Conclusions: :
Retinal thickness in the papillomacular bundle is markedly reduced in glaucoma patients and significantly correlated with increasing morphologic glaucomatous damage. Bruch’s membrane as a fixed reference detected by high resolution spectral domain optical coherence tomography may help to increase diagnostic performance in means of increased specificity of widely used tomographic optic disc evaluation. Furthermore we propose that determination of Bruch’s membrane can serve as internal reference plane for longitudinal studies not only with OCT but also with HRT images.
Clinical Trial: :
www.clinicaltrials.gov NCT00494923
Keywords: imaging/image analysis: clinical • Bruch's membrane • optic disc