Cilioretinal Arteries and Macular Vasculature in Highly Myopic Eyes
Ophthalmology Retina, October 2020
Using optical coherence tomography angiography (OCTA), Zhu et al. set out to evaluate cilioretinal arteries and the macular vasculature in highly myopic eyes. They found that the presence of cilioretinal arteries in these eyes may improve the macular vasculature and influence visual function.
For this retrospective observational case series, the authors evaluated 481 patients with high myopia (481 eyes) in the Shanghai High Myopia Study database. They compared vessel density, fractal dimension, and foveal avascular zone in OCTA images of eyes with and without cilioretinal arteries between the two groups. Vessel distribution and visual acuity (VA) also were assessed. Main outcome measures were cilioretinal arteries, macular vasculature, and their associations.
All told, 82 eyes (17.05%) had a cilioretinal artery. These eyes had significantly higher vessel density values, higher fractal dimension values for both the superficial and deep vascular plexuses, and a significantly smaller foveal avascular zone than did eyes with-out cilioretinal arteries. However, these differences were not found in the sub-group of eyes with an axial length of more than 30 mm. Best-corrected VA was better in eyes with cilioretinal arteries than in those without (0.09 ± 0.14 logMAR vs. 0.21 ± 0.27 logMAR, respectively). This was particularly true in eyes in which the cilioretinal artery reached the central foveal area.
This constellation of findings suggests that “the volume of the macular vasculature and the complexity of vascular branching in both the superficial and deep capillary layers were improved by the additional perfusion to the macula from the cilioretinal artery,” the authors wrote. With regard to the lessened impact in eyes with longer axial lengths, they suggested that the cilioretinal artery in these eyes is stretched and distorted and, as a result, is unable to provide sufficient additional perfusion.
The authors also noted that some features can confound VA results, including the presence of cataracts and age-related macular degeneration. Thus, additional studies are needed to tease out the potential protective effect of the cilioretinal artery in highly myopic eyes.
The original article can be found here.