Abstract
Purpose :
Peripapillary OCT-A scans are a challenge for analysis as VD is dependent on demarcation of the optic disc. Longitudinal VD analysis require that each pixel of the OCT-A scan has to be at the exact same location during follow-up scans in order to see inter-visit differences. Aim of the present study was to investigate BMO-based peripapillary OCT-A analysis with and without implementation of the Anatomical Positioning System (APS; Glaucoma Module Premium Edition [GMPE], Heidelberg Engineering, Germany) compared to manual analysis in healthy eyes.
Methods :
Thirty-seven eyes of 37 controls were measured twice by en-face OCT-A (Heidelberg OCT II Spectralis). OCT-A data were analyzed by the Erlangen Angio-Tool (EA-Tool, version 3.0), implementing an APS-based analysis of the peripapillary region in addition to implementation of BMO landmarks. The APS function allows alignment of OCT-A scans according to each individual FoBMOC (Fovea-to-Bruch’s Membrane Opening-Center) axis. APS and BMO coordinates were exported by SP-X1902 software (Heidelberg Engineering, Germany). Peripapillary OCT-A scans were analyzed: (I) manually (circle fitted on the shortest distance of the vertical or horizontal diameter of the optic disc), (II) BMO-based, and (III) BMO-based with APS information. II and III allowed an equidistant measurement of VD from BMO. The study was approved by the local ethics committee and was done in accordance with the tenets of the Declaration of Helsinki. Informed consent was obtained from each participant. Data were presented as mean ± standard deviation. Coefficients of variation (CV) were calculated. T-tests for paired samples were done.
Results :
Peripapillary mean VD was 42.7±16 and 41.1±19 (manually), 50.5±15 and 48.8±16 (BMO-based), and 44.7±11 and 44.4±15(BMO-based and APSifyed) for 1st scan and 2nd scan, respectively. Peripapillary mean VD yielded a significant difference between the 1st and 2nd scan for manual (p=0.02) and BMO-based (p=0.04), yet not for BMO-based and APSifyed analysis (p>0.05). CV were 10.0 (manually), 8.0 (BMO-based), and 8.0 (BMO-based and APSifyed).
Conclusions :
The novel integration of BMO landmarks into the EA-Tool allows a BMO-based peripapillary VD analysis, taking into account individual optic disc anatomy. Additional implementation of APS information increases reproducibility for longterm OCT-A studies of the peripapillary region.
This is a 2021 ARVO Annual Meeting abstract.