Group-Based Trajectory Modeling to Identify Factors Influencing the Development of Myopia in Patients Receiving Orthokeratology.

Purpose: To analyze the factors influencing the progression of myopia in adolescents receiving orthokeratology. Methods: This prospective cohort study collected the data of 378 myopia patients receiving orthokeratology. The follow-up time was 12 months ranging from December 2015 to December 2019. The group-based trajectory modeling (GBTM) was used to identify similar developmental trajectories in the levels of uncorrected visual acuity and changes of axial length elongation. Univariate and multivariate logistic regression analyses were conducted to explore the influencing factors of myopia development in patients wearing orthokeratology. Results: There was no factor having effect on visual acuity (left) and visual acuity (right) in different trajectories (all P>0.05). The corneal curvature K1 (left) (OR=0.382, 95% CI: 0.188-0.776), corneal curvature K2 (left) (OR=0.362, 95% CI: 0.187-0.699), degree of spherical refraction (left) (OR=0.139, 95% CI: 0.082-0.235) and spherical equivalent (left) (OR=7.276, 95% CI: 3.724-14.215) were factors associated with the changes of axial length elongation (left). The corneal curvature K1 (right) (OR=0.260, 95% CI: 0.116-0.585), corneal curvature K2 (left) (OR=0.272, 95% CI: 0.121-0.610) and degree of spherical refraction (right) (OR=0.129, 95% CI: 0.068-0.244) were correlated with the changes of axial length elongation (right). All P<0.05. Conclusion: Orthokeratology is a promising method for controlling the progression of myopia. The corneal curvature, degree of spherical refraction and spherical equivalent were factors influencing the changes of axial length elongation in myopia patients wearing orthokeratology. The findings might give a reference for the application of orthokeratology in clinic.

[Changes of opsin expression in experimental form-deprivation and defocus myopia in guinea pig].

OBJECTIVE: To investigate the opsin expression in form-deprived and defocus myopia in guinea pig and to study the relationship between the opsin expression and the experimental myopia. METHODS: Fifty guinea pigs were randomized into form-deprived group, defocus group (n = 20 in each group) and normal group (n = 10). Guinea pigs in form-deprived group wore a diffuser RGP on one eye since one week after birth. Those in defocus group wore -4.00 D RGP on one eye. The contralateral eyes wore 0 D RGP were used as the control. Refraction, axial length and depth of vitreous cavity were measured after 1 and 2 weeks. Animals were sacrificed and the retina were dissected at 10:00 - 12:00 AM. The level of opsin and its mRNA were measured by Western-blot and real-time PCR, respectively. RESULTS: Two weeks after the experiment, the refraction in form-deprived group and defocus group were (-4.00 ± 0.87) and (-2.00 ± 1.17) D respectively, which were significant different compared with contralateral eyes or normal control group (F = 203.98, 88.66, P < 0.05). These also accompany with increase of axial length and depth of vitreous cavity in form-deprived group and defocus group. Expression of S-opsin mRNA were increased both in form-deprived and defocus groups and the ratios of S-opsin mRNA/ß-actin expression were 0.752 ± 0.05 and 1.117 ± 0.13 in two weeks treatment, which were significant different from contralateral eyes (the ratios of S-opsin mRNA/ß-actin expression were 0.536 ± 0.04 and 0.772 ± 0.10.t = 6.10, 6.28, P < 0.05). Similar findings were also demonstrated in the expression of L-opsin mRNA, which were increased in form-deprived group and defocus group (the ratios of L-opsin mRNA/ß-actin expression were 0.42 ± 0.01) compared with contralateral eyes (the ratios were 0.24 ± 0.0 and 0.34 ± 0.04. t = 6.30, 4.93, P < 0.05) after two weeks experiment. The western-blot results also indicated the high expression of S-opsin and L-opsin level compared to contralateral eyes in form-deprived and defocus groups. CONCLUSIONS: Cone might be the detector receiving the signal of form-deprivation and defocus. Changes of opsin expression might play a role in the occurrence of experimental myopia in guinea pig.

Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model.

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model. EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter.