|Researchers found the choroid of more myopic eyes to be thicker than less myopic eyes. Note: Image is not from a patient in the study. Photo: Jim Williamson, OD, Meagan Williams, OD. Click image to enlarge.
A recent study reported an overall thinner choroid in more myopic eyes, with an increased flow void and reduced choriocapillaris vascular density in the more myopic eyes of children with anisometropia exceeding 1.50D.
The study sample included 44 participants with anisometropic myopia, aged nine to 18 years, with normal best-corrected visual acuity. All participants underwent a series of examinations, including spherical equivalent refraction (SER) and axial length (AL). OCT measured the choroidal thickness, vascular density and flow voids of the choriocapillaris. The choroidal thickness was measured at the fovea and 0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm and 3.0mm nasally, temporally, inferiorly and superiorly to the fovea. The vascular density and the flow voids of the choriocapillaris were measured at a 0.6mm-diameter central circle and at a 0.6mm- to 2.5mm-diameter circle in the nasal, temporal, inferior and superior regions.
The choroidal thickness of the more myopic eyes was significantly thinner than that of less myopic eyes, and the flow voids in the more myopic eyes were more than those of less myopic eyes. There was no significant difference in the vascular density of the choriocapillaris between the more and less myopic eyes. However, when anisometropia was more than 1.50D, the vascular density of choriocapillaris in the more myopic eyes was significantly less than the less myopic eyes. The interocular difference of the choroidal thickness was significantly correlated with the interocular difference in SER and AL in the center, superior and inferior regions but not in the nasal or temporal regions. The interocular differences of the vascular density and the flow voids of the choriocapillaris were not correlated with the interocular differences of SER and AL.
Despite their findings, the research team concluded, “The association between myopia and choroidal blood flow requires further investigation.”
Liu X, Lin Z, Wang F, et al. Choroidal thickness and choriocapillaris vascular density in myopia anisometropia. Eye Vis. December 2, 2021. [Epub ahead of print].