AIM: To observe the macular retinal microvascular density and thickness of each retinal layer in children with monocular myopia by optical coherence tomography angiography(OCTA). Meanwhile, the correlation with the above-mentioned retinal parameters and axial length(AL)were analyzed.

METHODS: A cross-sectional study. A total of 32 children(64 eyes)with monocular myopia who were treated at the Affiliated Eye Hospital of Nanjing Medical University from November 2020 to April 2021 were selected,with an average age of 10.88±2.34 years old. According to the spherical equivalent refraction(SER)of the children, SER≤-0.75D was included in the myopia group, with an average SER of -2.15±1.10D; The contralateral healthy eye was included in the non-myopia group, with an average SER of 0.01±0.48D. All participants underwent general ophthalmic examination and OCTA was performed to measure the blood flow density of superficial retinal capillaries(SCP), deep retinal capillaries(DCP)blood flow density and the thickness of each retinal layer in the macular region.

RESULTS: The uncorrected visual acuity(UCVA)of the myopia group was lower than that of the non-myopia group, the SER and AL were higher than those of the non-myopia group(all P<0.01), and there was no difference in intraocular pressure and corneal flatness K value(all P>0.05). The blood flow density of SCP above the macular area and the DCP blood flow density of the fovea in the myopia group were significantly higher than those in the non-myopia group(P=0.029, 0.010), and there was no difference in the blood flow density of retinal capillaries in other regions(all P>0.05). Except for the fovea, the whole retinal thickness of myopia group in temporal, superior, nasal and inferior regions was significantly lower than those in the control group(all P<0.01). The temporal inner retinal thickness of the macular region in the myopia group was slightly lower than that in the non-myopia group(P=0.043). The macular fovea and the outer retinal thickness of the temporal, superior, nasal and inferior macular areas in the myopia group were significantly smaller than those in the non-myopia group(all P<0.05). Pearson correlation analysis showed that foveal SCP and DCP blood flow density were positively correlated with AL(r=0.432, 0.541, all P<0.01). AL was significantly positive correlated with inner retinal thickness in macular central, temporal, superior, nasal and inferior regions(r=0.452, 0.389, 0.313, 0.401,0.445, all P<0.05). AL was negative correlated with outer retinal thickness in superior, nasal and inferior regions(r=-0.308, -0.309, -0.330, all P<0.05).

CONCLUSION: There was a compensated increase of blood flow density in superior SCP and macular central DCP of the myopic eyes in unilateral myopic children. The full-thickness retinal thickness was significantly reduced in the macular region, except for the fovea. The AL elongation was related to the thickening of the inner retina, as well as the thinning in the superior, nasal, and inferior regions of outer retina.