Choroidal Blood Flow Change in Eyes With High Myopia
Narrative Responses:
Purpose
To evaluate the choroidal blood flow change in eyes with high myopia by
pulsatile component of ocular blood flow analysis.
Methods
A total of 104 subjects (52 men and 52 women) were included in this study. One eye of each participant was randomly selected and assigned to one of four refractive groups: hyperopes (N=20, refractive error:≥+1.00D), emmetropes (N=28, refractive error:±0.75D), lower myopes (N=33, refractive error:-1.00 to -4.75D), and high myopes (N=23, refractive error:≤-5.00D). The pulse amplitude (OBFa), pulse volume (OBFv), pulse rate (OBFr), and pulsatile ocular blood flow (POBF) were analyzed using a Blood Flow Analyzer (BFA). Intraocular pressure (IOP) and axial length were measured.
Results
OBFa, OBFv, and POBF showed positive correlation with refractive error and showed negative correlation with axial length (r=0.729, r=0.772, r=0.781, respectively, all p<0.001 and r=-0.727, r=-0.762, r=-0.771, respectively, all p<0.001). The correlation of refractive error and axial length with OBFr was irrelevant (r=-0.157, p=0.113 and r=0.123, p=0.213). High myopes showed significantly lower OBFa, OBFv, and POBF than the other groups (all p<0.001).
Conclusion
Axial length change in high myopes could influence choroidal blood flow, assuming the change is caused by narrowing of the choroidal vessel diameter and increasing rigidity of the choroidal vessel wall, which explains the influence on OBFa, OBFv, POBF and not on OBFr.