Changes of retinal vessel density in low to moderate myopic eyes with orthokeratology evaluated by optical coherence tomography angiography.

AIM: To explore the effect of orthokeratology (OK) fitting on retinal vessel density in low to moderate myopia adolescents by using optical coherence tomography angiography. METHODS: Children aged 10 to 14y with a cycloplegic spherical equivalent refraction of -0.50 diopter (D) to -5.00 D and astigmatism with more than -1.50 D were recruited. The enrolled adolescents were divided into OK group and spectacle group. During regular follow-up, adolescents were measured respectively at pre-wear, 1, 3, and 6mo after treatment. The follow-up included uncorrected distance visual acuity (UDVA), axial length (AL), superficial capillary plexus density (SCPD), deep capillary plexus density (DCPD), central retinal thickness (CRT), foveal avascular zone area (FAZ-A), foveal avascular zone perimeter (FAZ-P) and foveal vessel density in a 300-µm-wide region around foveal avascular zone (FD-300). The collected data were analyzed using statistical methods. RESULTS: By one month, SCPD significantly increased in the fovea and superior retina, and DCPD significantly increased inferiorly in OK group compared to spectacle group (P<0.05). By three months, there were significant increases in SCPD in the fovea and inferior retina, and DCPD in the parafovea, superior, and inferior retina in OK group (P<0.05), while the increase in SCPD and DCPD in the fovea were observed by six months (P<0.05). The FD-300 significantly increased at every follow-up in OK group compared to spectacle group (P<0.05). No significant differences in the CRT, FAZ-A and FAZ-P and FD-300 were observed between two groups (P>0.05). OK group showed a significant improvement in UDVA after wearing OK, compared to spectacle group (P<0.01), while the AL did not show a significant difference between two groups (P>0.05). CONCLUSION: Short-term OK worn can increase local retinal vessel density in adolescents with low-to-moderate myopia.

Inhibition of the oxidative stress-induced miR-125b protects glucose metabolic disorders of human retinal pigment epithelium (RPE) cells.

The dysfunction of retinal pigment epithelium (RPE) with aging leads to age-related macular degeneration (AMD). Oxidative stress has been demonstrated as one of the causes of retinal pathological conditions. This study was conducted to investigate the mechanism of hydrogen peroxide (H2O2) induced human retinal pigment epithelial (RPE) cell dysfunction. We report miR-125b is induced by H2O2 treatments in RPE cells. In addition, we observed inhibited glucose metabolism under oxidative stress. Overexpression of miR-125b promotes the disorders of cellular glucose metabolism through direct targeting Hexokinase 2 (HK2). Restoration of HK2 in H2O2 treated RPE cells prevents the oxidative stress-suppressed glucose metabolism. Inhibition of the H2O2-induced miR-125b by inhibitor significantly prevented disorders of glucose metabolism. This study will contribute to the development of the miRNA based therapeutic approaches for against the oxidative stress-mediated human AMD.