Purpose: We aimed to observe longitudinal changes in retinal blood flow (RBF) and structural transformations in capillaries using Doppler optical coherence tomography (DOCT) and optical coherence tomography angiography (OCTA) in a feline retinal blood occlusion (RVO) model.
Methods: RVO was induced by argon green laser photocoagulation (PC) in six eyes of six cats. RBF was measured at a first-order retinal artery and vein by a DOCT flowmeter, and structural changes in the capillaries around the occluded vessels (12 × 12 and 3 × 3 mm) were assessed by OCTA before (at baseline); immediately after PC; and on days 1, 4, 7, and 14 thereafter. Systemic and ocular parameters were monitored during the observation period.
Results: There were no significant differences in any systemic or ocular parameters before and after PC. Arterial RBF increased significantly on day 1 (160.6 ± 8.6% vs. baseline, P < 0.001) and decreased below baseline after day 1 through 14. Venous RBF decreased immediately after PC (17.4 ± 9.6% vs. baseline, P = 0.001) and then gradually increased afterwards, but did not return to baseline. OCTA showed dilatation of retinal venules immediately after PC to day 1. Collateral vessels began to form on day 4, had matured by day 7, and were pruned on day 14, which formed as mature as normal retinal venule diameters.
Conclusions: With increasing arterial RBF within 1 day after inducing RVO, venules gradually expanded to form collateral vessels, suggesting that collateral vessels originate from existing capillary networks, not neovascularization.
Repeatability and Reproducibility of Retinal Blood Flow Measurement Using a Doppler Optical Coherence Tomography Flowmeter in Healthy Subjects.Invest Ophthalmol Vis Sci. 2017 Jun 1;58(7):2891-2898. doi: 10.1167/iovs.16-21389. Invest Ophthalmol Vis Sci. 2017. PMID: 28586913
Comparative Study of Optical Coherence Tomography Angiography and Phase-Resolved Doppler Optical Coherence Tomography for Measurement of Retinal Blood Vessels Caliber.Transl Vis Sci Technol. 2018 Aug 24;7(4):18. doi: 10.1167/tvst.7.4.18. eCollection 2018 Aug. Transl Vis Sci Technol. 2018. PMID: 30159211 Free PMC article.
Evaluation of Retinal Circulation Using Segmental-Scanning Doppler Optical Coherence Tomography in Anesthetized Cats.Invest Ophthalmol Vis Sci. 2016 Jun 1;57(7):2936-41. doi: 10.1167/iovs.15-18303. Invest Ophthalmol Vis Sci. 2016. PMID: 27273591
Optical Coherence Tomography Angiography in Eyes with Retinal Vein Occlusion.J Ophthalmic Vis Res. 2018 Jul-Sep;13(3):315-332. doi: 10.4103/jovr.jovr_264_17. J Ophthalmic Vis Res. 2018. PMID: 30090189 Free PMC article. Review.
Retinal oximetry and systemic arterial oxygen levels.Acta Ophthalmol. 2018 Nov;96 Suppl A113:1-44. doi: 10.1111/aos.13932. Acta Ophthalmol. 2018. PMID: 30460761 Review.