Abstract
Purpose: :
Evaluation of retinal vessels in cardiovascular disease traditionally relies upon funduscopy, more recently digital photo analysis has expanded the spectrum. As spectral domain optical coherence tomography allows an in-vivo assessment of retinal tissue and its vessels on a histological scale our study aimed at using this tool for the analysis of the retinal vasculature.
Methods: :
Circumferential peripapillar OCT scans (3D OCT 2000, Topcon Inc.) and simultaneous digital non-mydriatic 45° fundus photos with centration on the optic nerve head and were taken from 20 eyes (10 participants) with normal blood pressure and 20 eyes (10 participants) with arterial hypertension above 120mmHg (mean blood pressure). The diameter of all vessels intersecting the scan line was measured in the OCT and used to calculate central vessel equivalents. Designation to arteries vs. veins was ascertained through the fundus photo. A Matlab-based (Mathworks, USA) software tool was used for measuring the arterial and venous width on fundus photos and to calculate central vessel equivalents. A/V ratios were calculated for all four groups and correlation coefficients were determined for the two methods as well as with the individual mean arterial blood pressures.
Results: :
40 eyes of 20 persons were included in the study. Mean arterial blood pressure was 96mmHg (SD 4) in the control group and 132mmHg (SD 7) in the hypertonic group. Mean AV-ratio as determined from OCT scans was 0.83 (SD 0.16) (normotonic) vs. 0.63 (SD 0.11)(hypertonic). Mean AV-ratio on fundus images was 0.88 (SD 0.6) for the control group and 0.75 (SD 0.07) for the hypertonic group. The correlation coefficient for the comparison of the two vessel measurement methods was 0.51. A correlation coefficient of 0.81 (OCT) respectively 0.82 (funduscopic) was determined for the two groups. Dependency on blood pressure was on fundus photos -0.69, while on OCT scans -0.60.
Conclusions: :
Our results highlight the feasibility of retinal vessel measurements in spectral domain OCT. The comparison displays a non-inferiority as compared to fundus photo assessment. To our knowledge this is the first study to test a similar approach for hypertensive retinopathy. Further research will elucidate influencing factors and provide a broader basis for therapeutic approaches.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • imaging/image analysis: non-clinical