Analysis Of The Influence Factors On The Axial Length Of Teenagers After Orthokeratology Treatment

Background and purpose:Myopia is a common disease.In East Asia,the incidence of myopia is 80%to 90%.A large number of studies have shown that orthokeratology lens can effectively control the axial length growth of myopia patients and inversely reduce the equivalent diopter.There are many studies on the mechanism of the control of myopia by orthokeratology lens and its influence on the cornea,but there are few reports on the influence of pupil area and defocus ring area on the control effect of orthokeratology lens.In this study,a retrospective analysis of medical records was used to study the relationship between the decentration of orthokeratology lens、pupil area、defocus ring area and the axial length after wearing orthokeratology lens.Objective:By studying the correlation between axial length,baseline spherical equivalent,defocus ring area,AL/CR ratio and other factors,the influence of each factor on the effect of orthokeratology lens in controlling myopia progression and slowing the growth of the axial length was explored,providing a new basis for clinical fitting of orthokeratology lens lens and evaluating the therapeutic effect.Methods:Totally 70 patients,including 32 males and 38 females,who were treated in the Affiliated Eye Hospital of Nanchang University and wore orthokeratology lens for more than one year were selected.Spherical equivalent,corneal curvature radius,ocular axial length were measured before wearing the lenses.Decentration of orthokeratology lens,pupil area and defocus ring area were measured after wearing the lenses for three months.Data were collected and analyzed.Annual axial growth was used to evaluate the effect of orthokeratology lens on myopia control.Results:1.The axial length of the patient before wearing the orthokeratology lens was24.94±0.8mm,the axial length of the patient after wearing the orthokeratology lens was 25.09±0.79mm,and the annual axial growth was 0.15±0.18mm.The difference between the axial length before and after wearing the orthokeratology lens was statistically significant(P＜0.001)2.The average age of patients was 11.02±2.03 years old,which was negatively correlated with the annual axial length growth(r=-0.399,P＜0.001)3.The spherical equivalent of patients before wearing the orthokeratology lens was-3.15±1.16D,which was positively correlated with the annual axial length growth(r=0.321,P=0.001)4.The decentration of orthokeratology lens was 0.82±0.28 mm,which was negatively correlated with the annual axial length growth(r=-0.371,P＜0.001)5.The average pupil area of patients was 21.60±4.48 mm~2,which was positively correlated with the annual axial length growth(r=0.246,P＜0.05)6.The average AL/CR was 3.14±0.32,which was negatively correlated with the annual axial length growth(r=-0.269,P=0.006)7.There was no significant correlation between corneal radius of curvature and gender、pupil area and axial length growthConclusion:Orthokeratology lens has a better effect on controlling the axial length growth of patients with older wearing age,higher diopter,larger AL/CR ratio larger treatment zone decentration and smaller defocus ring area.