Retinal Microvasculature Alteration in High Myopia.
OBJECTIVE
To investigate the retinal vascular network alterations in highly myopic eyes.


METHODS
Thirty-three highly myopic eyes from 21 subjects and 47 mildly myopic or emmetropic eyes from 24 healthy control subjects were enrolled. Optical coherence tomography angiography (OCTA) was used to image the superficial, deep, and whole retinal vascular plexuses at the macular region. Highly myopic eye images were analyzed after adjusting the ocular magnification using Bennett's formula. Fractal analysis (box counting method, Dbox) representing vessel density was performed in different annular and quadrantile zones of both large vessels and microvessels. Correlations between the vascular density, axial length, and spherical equivalent refractive error were analyzed.


RESULTS
The average density (Dbox) of the superficial retinal annular zone (0.6-2.5 mm) microvessels was 1.741 ± 0.018 in highly myopic eyes and was shown to be significantly lower than that of the controls (1.773 ± 0.010, P < 0.001). Individual annular zone (bandwidth of 0.16 mm) analysis of highly myopic eyes revealed a significant level of microvessel alteration in all zones compared with the same zones in control eyes (P < 0.001). Furthermore, in the highly myopic group, the microvessel density was significantly correlated with axial length elongation in all three layers (r = -0.38 to -0.48; P < 0.05).


CONCLUSIONS
This study reveals retinal microvascular network alterations in highly myopic eyes, which correlates with axial length elongation. Fractal analysis of the microvasculature by OCTA images may help to characterize the underlying pathophysiological mechanisms involved in high myopia.
School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China 2Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States.
Ye
Y
Yang
Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States.
Jianhua
J
Wang
Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States.
Hong
H
Jiang
School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
Xiaoling
X
Yang
School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
Limiao
L
Feng
School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China 2Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States.
Liang
L
Hu
Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, Massachusetts, United States.
Liang
L
Wang
School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
Fan
F
Lu
School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
Meixiao
M
Shen
D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D055806:Microvessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009216:Myopia / Q000175:diagnosis / Q000503:physiopathology*; D012160:Retina / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012171:Retinal Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D041623:Tomography, Optical Coherence / Q000379:methods*