The Effect Of Orthokeratology Lens To The Biometric Parameters In Teenagers Of Myopias

Myopia is a major public health problem in the world.It is also one of the major social problems in the world.Now Ortho-keratology lens is an effective method to control and interfere with the progress of myopia.At present,the corneal thickness,corneal epithelium and endothelial cells,conjunctival complications and ocular axial changes were observed.We designed this research to study the effects of wearing Ortho-keratology lens on the biometric parameters of the eyes.Part Ⅰ:Comparison of the accommodative response with two refractive correctionsfor myopic teenagersObjectives To compare the effects of Ortho-keratology lens and single-focus frame glasses on the accommodative responses of myopic teenagers.Methods A total of 100 children were selected,and 50 were randomly divided into the Ortho-keratology lens group(Ⅰ group)and 50 people in the frame glasses group(group Ⅱ).The changes of diopter,eye axis and accommodative parameters before and after treatment were measured.Results There was no significant difference of the equivalent spherical after 1 year in group Ⅰ(P>0.05).The diopter of Group Ⅱ was increased compared with that before wearing and the difference was significant(P<0.05).There was no significant difference in axial length between the two groups before treatment(P>0.05).There was no significant difference in the axial length of the Group Ⅰ before and after the treatment after one year(p>0.05).But there were no significant difference of the Group Ⅱ(P<0.05).After 1 year,the accommodative lag of Group Ⅰ was significantly lower than that before treatment(P<0.05),and no statistical change was found in group Ⅱ.After 1 year,the adjustment lag of Group Ⅰ was significantly lower than that before correction(P<0.05),and no statistical change was found in Group Ⅱ.After 1 year’s review,accommodative sensitivities of the two groups were improved(P<0.05),and Group Ⅰ was more significant than group Ⅱ(P<0.05).Conclusions After 1 year of observation,Group Ⅰ was more effective in improving the accommodative response,significantly reducing the accommodative lag and increasing the sensitivity of the accommodation than Group Ⅱ.The improvement of accommodation lag maybe is one of the factors to slow the progress of myopias in Ortho-keratology Group.Part Ⅱ: Clinical observation of the changes in corneal astigmatism with general and Toric orthokeratology using vector analysisObjective To evaluate the effectiveness of general and Toric orthokeratology for corneal astigmatism changes in myopia children with moderate-to high astigmatism using vector analysis.Methods Case control study.14 patients(27 eyes)were fitted with spherical ortho-k lenses and 10 patients(20 eyes)were fitter with Toric ortho-k lenses.Data collection was performed periodically.Changes in corneal toricity were evaluated using vector analysis.Results The median subjective myopia,Corneal vector JO and J45 of group Ⅰ、Ⅱ at base line were no difference(P>0.05).After post-wearing OK lens 1 day、1week、lmonth,UCVA and Corneal vector J45 of group Ⅰ、Ⅱ were no difference(P>0.05).Corneal vector JO of group Ⅰ is less than that of group Ⅱ.After 3 months UCVA and Corneal vector JO of group Ⅰ、group Ⅱ have differences(P<0.05).Corneal vector J45 has no difference(P>0.05).Patients of group Ⅰ and Ⅱ,reporting visual disturbance symptoms,were 14.8%and 0%.Conclusions Both spherical ortho-k and Toric ortho-k can improve UCVA in myopia children with moderate-to-high astigmatism.But Toric design can be effective for improving CL fitting and enhancing corneal reshaping effect.No significant complications occurred during follow-up.Part Ⅲ: Analysis of changes in ocular pressure caused by the change of ocular biometric parameters in adolescents after Ortho-keratology lensesObjects To compare the effects of changes in ocular pressure changes caused by the changes of ocular biometric parameters in the eyes of adolescents after Ortho-keratology.Methods Eighty cases of adolescent children were selected from the department of our hospital.The relationship between corneal thickness,anterior chamber depth and intraocular pressure changes were compared.Results The corneal curvature was decreased after 1 week of wearing(P<0.05),and no significant changes were observed in the follow-ups.The corneal thickness was no significantly changed after 1 week(P>0.05)and decreased in 1 month(P<0.05),but tended to be stable after that(P>0.05).There was no significant change in the anterior chamber depth after wearing lens(P>0.05),The changes of intraocular pressure were significantly reduced after wearing lens(P<0.05).Conclusion Ortho-keratology len is used to improve the visual acuity by changing the curvature of the cornea,The biological measurement parameters and the intraocular pressure will change accordingly.The treatment process is safe and effective.