Effects on radius of curvature and refractive power of the cornea and crystalline lens by atropine 0.01% eye drops.

PURPOSE: The morphological changes in the cornea and crystalline lens have not been closely evaluated after the administration of atropine 0.01%. This study aims to evaluate the radii of curvature and refractive power of the cornea and lens in myopic eyes during atropine 0.01% treatment. METHODS: Children aged 6-14 years with myopia <-6.0 D were randomized to receive atropine 0.01% once nightly with single vision lenses or simply wear single vision lenses. Ocular biometric parameters were measured using the IOLMaster 700 biometry and the radii of corneal and lenticular curvature were simulated using a customized program. RESULTS: At the 9-month visit, 69 atropine-treated eyes and 50 control eyes were included in the final analyses. In atropine-treated eyes, the posterior corneal surface steepened (-0.05 ± 0.13 mm) and the anterior lenticular surface flattened (0.20 ± 0.69 mm) significantly within 3-6 months, whereas the posterior corneal surface and anterior lenticular surface gradually flattened (0.07 ± 0.23 and 0.32 ± 0.80 mm respectively) in the control eyes over 9 months. The difference in the change of corneal refractive power was significant between groups (-0.03 ± 0.18 D vs. 0.11 ± 0.24 D, p = 0.001), while that in the change of lenticular refractive power was statistically insignificant (0.01 ± 0.92 D vs. -0.22 ± 0.86 D, p = 0.161). CONCLUSIONS: The administration of atropine 0.01% exhibited a clinically short and subtle impact on the cornea and lens, which may shed light on new targets of action for atropine in inhibiting myopia.

Effects of atropine 0.01% on refractive errors in children with myopia.

Background: Little is known about changes in astigmatism during atropine treatment. We aimed to explore the effects of atropine 0.01% eye drops on both spherical and cylindrical refractive errors in myopic children. Methods: Children aged 6-14 years with myopia ≥ -6.00 D and < -0.50 D, and total astigmatism > -2.00 D in at least one eye were enrolled. Subjects were randomised either to receive atropine 0.01% once nightly with single-vision lenses or simply to wear single-vision lenses and were followed up at 3-month intervals. Cycloplegic refraction and axial length were measured. The magnitude and direction of total astigmatism (TA), corneal astigmatism (CA), and residual astigmatism (RA) were evaluated. Results: Overall, 119 eyes (69 eyes in the atropine group and 50 eyes in the control group) were included in the final analyses after 9 months. Atropine-treated eyes showed significantly less progression of myopia than did control eyes (spherical equivalent: -0.35 ± 0.33 vs. -0.56 ± 0.49 D, p = 0.001; axial length: 0.20 ± 0.19 vs. 0.33 ± 0.19 mm, p < 0.001). Compared with control eyes (-0.04 ± 0.23 D), a significant increase in TA was observed in the atropine-treated eyes (-0.14 ± 0.29 D); this was mainly attributed to the increase in CA (-0.17 ± 0.26 D) rather than the minor decrease in RA (0.02 ± 0.32 D). Conclusions: Atropine 0.01% was effective in preventing myopia progression, whereas 9 months of atropine treatment resulted in a clinically small, but statistically significant increase in TA in myopic Chinese children.

Corneal and lenticular biometry in Chinese children with myopia.

CLINICAL RELEVANCE: The measurement and simulation of corneal and lenticular curvature radii using a single swept-source biometry device enables a more thorough evaluation of the shape and refractive power of the cornea and lens during emmetropization or myopia progression in children. BACKGROUND: This study aimed to evaluate the distribution characteristics of corneal and lenticular parameters in Chinese children with myopia and explored their association with other ocular components. METHODS: In this cross-sectional study, all ocular biometric parameters were measured using a Zeiss IOLMaster 700 Biometry. Simulations of the corneal and lenticular curvature radii were implemented using a customised MATLAB program based on cross-sectional swept-source optical coherence tomography images obtained from the same device. The associations of the calculated and simulated refractive powers of the cornea and lens with other ocular parameters were evaluated. RESULTS: In total, 119 children with myopia were recruited. Boys had a deeper anterior chamber and longer axial length (AL) than girls, while girls had steeper anterior corneal and lenticular curvatures and greater corneal and lenticular power. Children aged 10 years and older showed a larger anterior lenticular radius of curvature (sRal) and less lenticular power (PL,OCT) than younger participants. There was a significant positive correlation between AL and the anterior corneal radius of curvature, regardless of sex or age. The sRal exhibited a significant increasing trend, and PL,OCT exhibited a declining trend with a longer AL only in children younger than 10 years. CONCLUSION: AL is the most influential factor in the determination of spherical equivalent refractive error, while decreases in both corneal and crystalline lens power are significantly inversely correlated with axial elongation.

Short-Term Effects of Atropine 0.01% on the Structure and Vasculature of the Choroid and Retina in Myopic Chinese Children.

INTRODUCTION: To explore the short-term effects of atropine 0.01% on the structure and vasculature of the choroid and retina in myopic Chinese children. METHODS: This study was a single-center randomized clinical trial. A total of 40 subjects with myopia < - 6.0 D were enrolled and randomized to receive atropine 0.01% once nightly with regular single-vision lenses or to simply wear regular single-vision lenses at an allocation ratio of 1:1. Follow-up visits were planned at 1 month and 3 months. Choroidal thickness (ChT) was obtained by optical coherence tomography (OCT). Retinal vessel density (RVD), retinal thickness (RT), foveal avascular zone (FAZ) and choriocapillaris flow (CCF) were measured by optical coherence tomography angiography (OCTA). The RVD and RT were measured at fovea, parafovea and perifovea area and four quadrants. RESULTS: Twenty-one subjects were allocated into the atropine group and 19 subjects into the control group. Over 3 months, the control group showed greater progression of myopia than those in the atropine group. ChT in the atropine group increased 11.12 ± 13.96 µm, which was not significant compared with that of the control group. None of the retinal sectors in atropine-treated eyes showed significant changes of RT and RVD compared with the control group. Besides, FAZ and CCF of the atropine group were not affected by atropine use over time, and there was no difference between the two groups. CONCLUSION: Administration of atropine 0.01% eye drops demonstrated no effect on RVD, FAZ and CCF over 3 months, while a modest increase of ChT was observed in atropine-treated eyes. TRIAL REGISTRATION NUMBER: ChiCTR1800017154.

Biometric measurement with a commercially available swept-source optical coherence tomography in myopia model species.

Background: Biometric parameters play an important role in studies on myopia. This study aimed to explore the application of a commercially available two-dimensional visualized swept-source optical coherence tomography (OCT) system, for in vivo biometric measurement in multiple myopia model species. Methods: In this study, chickens, guinea pigs, and C57BL/6 mice underwent eye imaging with the commercially available OCT (CASIA2), and the original images were used to calculate the central corneal thickness, anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL). The retinal thickness and choroidal thickness were also calculated in chicken eyes. The repeatability of the biometric measurement outcomes was analyzed. Results: Excellent repeatable AL measurements were obtained for all three species, with an intraclass correlation coefficient (ICC) of ≥0.941 and a within-subject standard deviation of ≤0.055. Excellent repeatability was found in chicken eyes for ACD, LT, and VCD, with an ICC of ≥0.932; in guinea pig eyes for ACD and VCD, with an ICC of ≥0.934; and in mouse eyes for LT, with an ICC of ≥0.941. Conclusions: It is effective to use commercially available OCT to measure biometric parameters in chickens, guinea pigs, and C57BL/6 mice. This methodology could potentially increase the accuracy and efficiency of future myopia animal experiments.

Seasonal and spatial distributions of morpho-functional phytoplankton groups and the role of environmental factors in a subtropical river-type reservoir.

Phytoplankton is capable of responding to aquatic conditions and can therefore be used to monitor freshwater reservoir water quality. Numerous classification techniques, including morpho-functional approaches, have been developed. This study examined changes in phytoplankton assemblages and water quality, which were sampled quarterly from July 2018 to April 2019. The purpose was to contrast the applicability of three classification approaches (functional, morpho-functional and morphological-based functional groupings) for understanding the spatial and seasonal distribution of the biomass variance in phytoplankton functional groups and their driving environmental factors in the ecological zones of the Shanxi Reservoir through multivariate analysis. The results showed that the phytoplankton biomass was highest in the watercourse zone and lowest in the transition zone. Furthermore, the Shanxi Reservoir was characterized by several cyanobacteria (Microcystis spp.) and numerous bacillariophytes (Asterionella sp., Navicula spp. and Aulacoseira granulata). After evaluating the advantages and disadvantages of morpho-functional classifications, we determined that water temperature appeared to be an essential factor, and the morphology-based functional group approach provided the best results for demonstrating phytoplankton succession, despite having lower sensitivity than the others. Nevertheless, these approaches are all appropriate for identifying and monitoring phytoplankton community structure in aquatic systems of reservoirs with complex terrains.

Spatial variations of soil phosphorus in bars of a mountainous river.

As an important part of the riparian zone, bars are an important barrier for the interception of phosphorus (P) originated from leaching and runoff. The spatial variation in P as well as the influence of factors on the said spatial variation in mountainous river (Lingshan River) bars was investigated. A total of 100 soil samples were collected from 11 sampling sites. Soil total phosphorus (TP) and soil available P were determined to explore the spatial variation of soil P in mountainous river bars. One-way analysis of variance, Pearson's correlation analyses, stepwise multiple linear regressions and curve fitting were used to explore the dominant factors affecting the spatial variation of soil P in mountainous river bars. Affected by erosion effect of flowing water, the TP of the bar soils decreased in the longitudinal direction, the TP and available P of the bar soils increased in the cross-sectional direction and the variation in TP between the surface and deep soils firstly increased and then decreased as the height of the bar above the water surface increased. The stronger the erosion effect of flowing water, the more P releases to the water, which may cause the spatial variation of soil P in mountainous river bars, and the results of this study facilitated control of non-point source pollution in mountainous river and restoration of the ecosystems in mountainous river bars.