Characteristics of the optic disc in young people with high myopia.

PURPOSE: This study aimed to investigate the characteristics of the optic disc in adolescents and young adults with high myopia by applying optical coherence tomography angiography. METHODS: A total of 112 patients with high myopia (spherical equivalent refraction (SER) ≤ -6.00 D) aged 12 to 30 years old were enrolled in this cross-sectional study. Parapapillary atrophy (PPA) and ovality index from scanning laser ophthalmoscopy images and the degree of optic disc tilt from the optic nerve head (ONH) OCT B-scans were analysed using ImageJ and MATLAB software. Peripapillary retinal nerve fibre layer thickness (pRNFLT) and radial peripapillary capillary vessel density (RPC VD) around the optic disc were obtained from the images of the optic disc angiography scan. RESULTS: In young high myopia patients, the PPA area was positively correlated with age, axial length (AL) and pRNFLT (all p < 0.05) and negatively correlated with SER (r = -0.222, p = 0.020). The degree of the optic disc tilt was associated with increasing AL and pRNFLT (all p < 0.05). The disc area was positively correlated with AL, pRNFLT, and RPC VD (all p < 0.05). In the multivariate regression analysis, PPA area was independently associated with the degree of optic disc tilt and disc area. The degree of optic disc tilt was affected by AL and PPA area while the change of disc area was influenced by PPA area and pRNFLT (all p < 0.05). CONCLUSION: In young patients with high myopia, PPA area, the degree of optic disc tilt and disc area increased with AL and pRNFLT, while decreased with SER. The association between these factors was slightly different in the adolescent and young adult groups. The degree of the optic disc tilt was more associated with AL and SER in the adolescent group while disc area showed more correlated with AL and SER in the young adult group.

Associations between optic disc characteristics and macular choroidal microvasculature in young patients with high myopia.

BACKGROUND: This study aimed to examine changes to optic disc characteristics and macular choroidal microvasculature, and their relationships in young patients with high myopia (HM). METHODS: A total of 90 patients were enrolled in this cross-sectional study. Based on their refractive power, the patients were divided into three groups: 27 in the control group, 34 in the HM group and 29 in the extremely high myopia group. Images of each patient's macula and optic disc were taken by ocular coherence tomography angiography. The macular choroidal and retinal thickness, capillary vessel density and capillary flow area were measured using Matlab software. Parapapillary atrophy (PPA) and the ovality index (OI) obtained from the scanning laser ophthalmoscopy images and the degree of optic disc tilt obtained from the optic nerve head ocular coherence tomography B-scans were analysed by Image J and Matlab software. RESULTS: The PPA area, OI and degree of optic disc tilt were significantly different among the three groups (all p ≤ 0.001). The macular choroidal thickness and microvasculature were significantly different among the three groups (all p < 0.05). Macular choroidal thickness was significantly correlated with PPA area and the degree of optic disc tilt (r = -0.331, p = 0.003; r = -0.394, p = 0.001, respectively). Macular choroidal capillary vessel density and choriocapillaris flow area were associated with PPA area (r = -0.251, p = 0.047; r = -0.326, p = 0.009, respectively). CONCLUSIONS: PPA area, OI and the degree of optic disc tilt were increased in patients with HM, and these changes were correlated with macular choroidal thickness and choroidal microvasculature.

The Effect of Corneal Refractive Power Area Changes on Myopia Progression during Orthokeratology.

Purpose: To investigate the effect of corneal refractive power area changes on myopia progression during orthokeratology. Methods: One hundred and sixteen children who met the inclusion criteria and insisted on wearing orthokeratology lenses for two years were retrospectively assessed. Seventy-two children with the orthokeratology lens decentration distance more than 0.5 mm but less than 1.5 mm were in the decentered group, and forty-four children with the orthokeratology lens decentration distance less than 0.5 mm were in the centric group. The orthokeratology decentration via tangential difference topography was analyzed. This study calculated the different power areas in the central 4 mm pupillary area by axial-difference corneal topography, compared the differences of the different power areas between these two groups, and evaluated the relationships between corneal positive-power area, orthokeratology decentration, and AL changes. Results: The axial length changes of the centric group presented a statistical difference with the decentered group (0.52 ± 0.37 mm vs. 0.38 ± 0.26 mm; t = 2.403, p=0.018). For all children, both the AL changes (0.43 ± 0.31 mm) and decentration distance (0.64 ± 0.33 mm) showed a significant correlation with the positive-power area (r = -0.366, p < 0.001 and r = 0.624, p < 0.001); AL changes also presented a statistical correlation with decentration distance (r = -0.343, p < 0.001), baseline age (r = -0.329, p < 0.001), and baseline spherical equivalent refractive power (r = 0.335, p < 0.001). In the centric group and decentered group, the AL changes (centric group: r = -0.319, p=0.035; decentered group: r = -0.332, p=0.04) and decentration distance (centric group: r = 0.462, p=0.002; decentered group: r = 0.524, p < 0.001) had a significant correlation with the positive-power area yet. In the multiple regression analysis, AL changes were increased with less baseline age (beta, 0.015; p < 0.001), positive-power area (beta, 0.021; p=0.002), and larger SER (beta, 0.025; p=0.018). Conclusions: The corneal positive-power area had a positive impact on affirming AL changes during orthokeratology. This area might be formed by lens decentration to provide an additional myopia-defocusing influence on the retina to achieve better myopia control.

Contrast Sensitivity Is Associated With Chorioretinal Thickness and Vascular Density of Eyes in Simple Early-Stage High Myopia.

Objective: To evaluate the contrast sensitivity function (CSF), chorioretinal thickness and vascular density as well as their relationships in subjects with simple early-stage high myopia. Methods: Eighty-one young subjects were enrolled in this study. They were categorized into the simple high myopia group (sHM, n = 51) and the low-moderate myopia group (control group, n = 30). Monocular CSF under best correction was measured with the qCSF method. Retinal superficial and deep vascular density, inner and outer retinal thickness and choroidal thickness were measured using optical coherence tomography angiography. Results: The area under log CSF (AULCSF) and cutoff spatial frequency (Cutoff SF) of the sHM group were significantly reduced compared to those of the control group (P = 0.003 and P < 0.001, respectively). The parafoveal and perifoveal retinal thickness, deep vascular density and choroidal thickness were also significantly reduced in the sHM group (all P < 0.05). Multiple regression analysis revealed that AULCSF was significantly correlated with retinal deep vascular density, outer retinal thickness in the parafoveal and perifoveal areas (all P < 0.05). Conclusion: Compared to low to moderate myopic eyes, patients with simple high myopia have thinner retinal and choroidal thickness, lower retinal vascular density, and reduced contrast sensitivity. Moreover, the CSF was correlated with the measures of chorioretinal structure and vasculature. The results suggest that the CSF is a sensitive functional endpoint in simple early-stage high myopia.