Choriocapillaris Flow Void Area May Predict Axial Elongation

Larger choriocapillaris flow void area at baseline may predict axial elongation in individuals with myopia who are treated with defocus incorporated multiple segments (DIMS) spectacle lenses, according to a study published in Eye.

Researchers included 106 children (age range, 7-14 years) with myopia who underwent DIMS treatment in a retrospective investigation to examine choroidal and ocular biological variables affecting axial growth. The team stratified participants according to axial length progression (slow progression: ≤0.2 mm/ year; n=39 vs fast progression: >2 mm/ year; n=67) and obtained cycloplegic autorefraction, axial length, choriocapillaris flow void area, and choroidal thickness measurements at baseline. Cycloplegic autorefraction and axial length measurements were repeated at 6- and 12- month follow-up visits. 

Average choroidal thickness was 255.86 μm and mean choriocapillaris flow void area was 2.25 mm² among the cohort, and mean baseline flow void area was significantly larger among participants with rapid axial progression compared with slow progression (2.30 vs 2.17 mm²), the report shows.

Axial elongation was significantly associated with choriocapillaris flow void area and age (both P  <.05). More myopia and larger flow voids were associated with a rapid axial elongation, while older age, larger pupil diameter, and steeper corneas protected against rapid axial growth.  

Choriocapillaris flow void area alone estimated axial elongation, with an area under the curve (AUC) value of 0.672 (95% CI, 0.569–0.775; P <.01). When this metric was combined with pupil diameter, average keratometry, and spherical equivalent refraction values, axial growth predicative ability increased (AUC, 0.788; 95% CI, 0.697–0.878; P <.001).

“The choroid plays a mediating role in the [signaling] pathway of ocular growth from the retina to the sclera, which is closely associated with the progression of myopia,” the study authors explain. “Hence, it is of great significance to evaluate choroidal blood flow in the progression of myopia and its efficacy for myopia prevention and control.”

Study limitations include a retrospective nature, single center design, small sample size, the strict inclusion of children treated with DIMS spectacles, and ethnic homogeneity among the cohort, which may limit the generalizability of these findings.