Assessment of choroidal vascularity and choriocapillaris blood perfusion in Chinese preschool-age anisometropic hyperopic amblyopia children

Abstract

Purpose: To determine the macular and peripapillary area choroid microstructure parameters of hyperopic anisometropic amblyopia eyes and compare to fellow and age-matched control eyes. To assess the correlation between the axial length (AL), choroidal thickness (CT) and choroid microstructure parameters.

Methods: This cross-sectional comparative, non-interventional study involved 52 hyperopic anisometropic amblyopia children and 48 age-matched heathy controls. 52 eyes with hyperopic anisometropic amblyopia and 48 age-matched control eyes were studied. The peripapillary and subfoveal CT were determined. The total choroidal area (TCA), luminal area (LA), and stromal area (SA) of the subfoveal and peripapillary choroid were measured. In addition, the correlation between the AL, CT and choroid microstructure parameters were calculated.

Results: The peripapillary and subfoveal CT of the amblyopic eyes was significantly thicker than the fellow and control eyes (all P < 0.05). The subfoveal and peripapillary choroidal SA, LA and TCA of the amblyopic eyes were significantly increased than that of the fellow and control eyes (all P < 0.05). The choroidal vascularity index (CVI) values of the amblyopic eye were significantly different among the three groups (P < 0.05). There was a statistically significant negative correlation between AL and subfoveal CT (SFCT), LA and TCA levels (P < 0.001, P = 0.039, P = 0.027, respectively). Spherical equivalent (SE) was positive correlated with SFCT, LA and TCA levels (P = 0.456, 0.229 and 0.240, respectively; all P < 0.05). There was a statistically significant positive correlation between SFCT, SE, LA, SA, TCA and CVI levels (all P < 0.05).

Conclusion: The subfoveal and peripapillary CT of amblyopic children abnormally increased and correlated with shorter AL and higher SE. The choroidal structure of the amblyopic eyes was different from the fellow and control eyes, the hyperopic anisometropic amblyopic eyes had significantly thicker sub-foveal choroid, higher LA, SA, and TCA. AL and CT affect choroidal structure and vascular density. Choroidal blood flow may be increased in amblyopic eyes. The larger LA, SA, TCA, and lower CVI were characteristic of the amblyopic eye.

Keywords: amblyopia; anisometropic; choriocapillaris blood perfusion choroidal thickness; choroidal vascularity index; hyperopia.

Figure 1

Subfoveal CT measurement. CT was measured at 7 points: directly beneath the fovea or the subfoveal area (SFCT) point, and 0.5/1.5/3 mm to the fovea nasally (N1/N2/N3), 0.5/1.5/3 mm to the fovea temporally (T1/T2/T3).

Figure 2

Comparison of choroidal structure of macula in a patient with anisometropia amblyopia. (A) Choroidal thickness of the hyperopic anisometropic amblyopia eye. (B) Choroidal thickness of the fellow eye.

Figure 3

Peripapillary RNFL and choroidal thickness measurement. The RNFL thickness data can be automatically calculated and displayed. For peripapillary choroidal thickness measurement, we manually moved the automatically segmented internal limiting membrane line to the choroid sclera junction and moved RNFL line to the retina pigment epithelial line. Once we changed the automatically segmented line, the choroidal thickness data were automatically calculated and displayed.

Figure 4

The subfoveal choroidal area and peripapillary choroidal area measurement. Using ImageJ software, the image was binarized with Niblack's method, and the ratio of vascular area (black pixels) to stromal area (white pixels) was quantified.

Figure 5

Choroidal thickness and vascular parameters among the three groups. The subfoveal choroidal thickness, temporal and nasal choroidal thickness, LA, SA, and TCA values of amblyopic eyes, fellow eyes, and controls.