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Robert Kromer, Sebastian Boelefahr, Armin Bartels, Sven Christian Beutelspacher, Maren Klemm; Evaluation of retinal vessel morphology in Open Angle Glaucoma using a novel Optical Coherence Tomography based method. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2964.
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© ARVO (1962-2015); The Authors (2016-present)
Open angle glaucoma (OAG) is one of the main causes of impaired vision worldwide. While several pathogenetic mechanisms have been proposed, it remains poorly understood. Alterations in ocular blood flow and an abnormal vascular circulation configuration seem to be major components in OAG. We use a novel method for facilitating the analysis of retinal vessel morphology: The intensity of the distal shadow of vessels caused by the reflected signal of spectral domain optical coherence tomography (SD-OCT) is analyzed and compared between healthy patients and OAG patients. We evaluate diagnostic technology in a prospective cross-sectional study.
Sample sizes were chosen using power analysis with 90% power based on preliminary results. Patients were divided into two cohorts (age-and sex-matched): 180 patients with diagnosed OAG (mean age 62.9 years, standard deviation 14.9 years) and 180 healthy control patients (mean age 61.5 years, standard deviation 13.8 years). All patients underwent extensive ophthalmic diagnostics including SD-OCT. The vessel shadow intensity (VSI) is based on peripapillary SD-OCT scans and automatically analyzes the intensity of the distal vessel shadow compared to its surroundings in three segmented layers. Segmentation used a mean filter and curve fitting-based regularization. One eye of each participant was randomly selected and used for statistical analysis (phenotype).
VSI was significantly altered in patients with diagnosed OAG in all three segmented layers (VSI Layer 1: difference between means 0.067 ± 0.073, p < 0.0001; VSI Layer 2: difference between means -0.037 ± 0.051, p < 0.0001, VSI Layer 3: difference between means -0.033 ± 0.1144, p = 0.0077). The retinal vessel morphology seemed to remain unaffected by disease progression, which was determined using visual field parameters (mean deviation and pattern standard deviation), Heidelberg Retina Tomograph and SD-OCT retinal nerve fibre layer thickness (p > 0.05).
We conclude that retinal vessel morphology is changed in patients with OAG. Furthermore, it seems that this change is independent from disease progression. Further prospective studies are needed to evaluate the prognostic value in early detection of the disease before other morphological or functional degeneration is observable.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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