ABSTRACT
@#AIM: To observe the changes of relative peripheral refraction(RPR)after wearing orthokeratology(OK)lens, and to explore the relationship between the changes of RPR and the axial length(AL).<p>METHODS: Totally 104 cases of adolescent myopia(-1.00D to -6.00D)were selected from May 2016 to Nov. 2018. Then they were randomly divided into the experimental group and the control group. The experimental group wore OK lens, and the control group wore frame glasses. Their AL, RPR(N30°-T30°)were observed for 1a.<p>RESULTS:The RPR of the experimental group showed myopic drift at each time point after wearing OK lens(<i>P</i><0.05), and the change was most obvious in 1mo(<i>P</i><0.05). After 1mo, the RPR basically tended to be stable(<i>P</i>>0.05). The RPR of the control group showed an increase in hyperopia. One year later, there were statistical differences in the changes of AL and RPR between the two groups(<i>P</i><0.001). There was a positive correlation between the changes of AL and RPR in the experimental group(<i>P</i><0.001).<p>CONCLUSION: After wearing OK lens, the AL growth slowed down, while the RPR showed myopic drift and it was most obvious in 1mo. There was a correlation between the changes of AL and RPR.
ABSTRACT
@#AIM:To observe the different effect of controlling myopia by orthokeratopraxis with different width between defocus circle and the rim around the cornea.<p>METHODS: A retrospective case-control study. A total of 45 patients(85 eyes)who came to our hospital for orthokeratopraxis lens fitting during January 2014 to December 2015 were selected. The diameter of the orthokeratopraxis lens was 90%-95% of the diameter of the cornea. So the patients were divided into three groups according to the different diameter of the orthokeratopraxis lens. The diameter of the orthokeratopraxis lens for the patients whose corneal diameter was between 12.1 to 13.00mm was 11.0-11.2mm(Group A). The diameter of the orthokeratopraxis lens for the patients whose corneal diameter was between 11.1-12.00mm was 10.5-10.9mm(Group B). The diameter of the orthokeratopraxis lens for the patients whose corneal diameter was between 10.0-11.00mm was 10.0-10.4mm(Group C). The change of the spherical equivalent(SE)and axial length(AL)were analyzed after wearing the lens for 1a and 2a.<p>RESULTS: Before wearing lens, the age, SE(D)and AL(mm)was not statistically significant in the three groups(<i>P</i>>0.05). After wearing lens for 1a and 2a, the change of SE(D)and AL(mm)was not statistically significant in Group A and Group B(<i>P</i>>0.05)and the change was statistically significant in Group C(<i>P</i><0.05). The change of the SE and AL was also significantly different between Group A and Group C after wearing orthokeratopraxis lens for 2a(<i>P</i><0.05). A similar result was found between Group B and Group C(<i>P</i><0.05).<p>CONCLUSION: The effect of controlling myopia by orthokeratopraxis with different position of defocus circle on cornea is different. The position of defocus circle is more close to the corneal limbus, the effect is weaker.