Choriocapillaris Flow Deficit Increases With Axial Growth, Perifoveal Area

Choriocapillaris(CC) flow deficit percentage (FD%) in the perifoveal area increases with longer axial length (AL) in eyes with non-pathological high myopia, according to research published in  the American Journal of Ophthalmology. This increase was not observed in the fovea or parafovea, according to the report. 

Researchers enrolled 1017 participants (mean age, 35.95±14.11 years; 56.05% women; mean AL, 27.01±0.73 mm) in a prospective, cross-sectional study to examine associations between AL and CC FD% in eyes with non-pathological high myopia (AL>26 mm; META-PM classification<2). Swept-source optical coherence tomography angiography (SS-OCTA) imaged the macular CC and CC FD% was assessed in the fovea, parafovea and perifovea subfields.

The report shows that overall CC FD% increased by 0.27% (95% CI, 0.02-0.52; P =.034) for each mm increase in AL. Longer AL was associated with an increased CC FD% in the perifovea (β=0.53; 95% CI, 0.30-0.77; P <.001), but not in the parafovea (P =.652) or fovea (P =.999).

“In this large sample of non-pathological highly myopic individuals, the mean CC FD% increased with axial elongation in the perifoveal region, but not in the foveal and parafoveal fields,” according to the researchers. “This study suggests that the effect of axial elongation on CC perfusion may occur first in the outer macular region.”

Study limitations include failure to include individuals who were not of Chinese ethnicity, failure to consider diurnal variation when assessing CC perfusion, and the exclusion of individuals with pathological high myopia.