Résumé
AIM: To evaluate the clinical efficacy of wearing base curve aspheric orthokeratology(OK)lens in the control of myopia.METHODS: A prospective study was conducted. A total of 94 cases(94 eyes)of myopia aged 8～13 years old who were fitted with orthokeratology(OK)lens in our hospital from January 2020 to July 2021 were selected(for patients who received OK lens in one eye, the eye is selected as the observation eye, and for patients who receive OK lens in both eyes, the right eye is used as the observation eye). Patients were divided into two groups according to the design of the OK lens, with 46 cases wearing base curve aspheric OK lens in study group and 48 cases wearing base curve spheric OK lens in control group. The study group and the control group were further divided into low myopia group(-3.00D< SE ≤-0.75D)and moderate myopia group(-6.00D< SE ≤-3.00D)according to the baseline spherical equivalent(SE), with 52 cases(52 eyes)in the low myopia group and 42 cases(42 eyes)in the moderate myopia group. Uncorrected visual acuity(UCVA)was evaluated at 1d, 1wk, 1, 3, 6 and 9mo after wearing lenses, and axial length were measured at 6mo and 1a after wearing lenses respectively.RESULTS: All patients completed follow-up, and there was no significant differences in UCVA(LogMAR)between the study group(-0.12±0.08)and the control group(-0.17±0.07)after wearing the OK lens for 1mo(P>0.05); the mean axial length elongation between the two groups had no significant differences after wearing lenses for 6mo and 1a(all P>0.05). In the low myopia group, the axial length elongation of the study group was 0.19±0.17mm after wearing OK lens for 1a, which was significantly lower than that of the control group(0.31±0.18mm; P<0.05); while in the moderate myopia group, the axial length elongation was 0.22±0.18mm, and it had no significant differences with that in the control group(0.19±0.12mm; P>0.05). There was no significant differences in axial length elongation between the low myopia group and the moderate myopia group in study group after wearing lenses for 6mo and 1a(P>0.05), while there was differences in axial length elongation between low myopia group and moderate myopia group in the control group after wearing lenses for 6mo(0.15±0.13 vs. 0.05±0.12mm)and 1a(0.31±0.18 vs. 0.19±0.12mm; all P<0.05).CONCLUSION: Wearing base curve aspheric OK lens can effectively improve the UCVA and control the elongation of axial length. For patients with low myopia, base curve aspheric OK lens had a better efficacy in controlling the elongation of axial length than the spheric OK lens.
Résumé
Context: The development of myopia and growth of the eye, occur at a time when body stature is increasing. Aims: To investigate the relationship of lifestyle and body growth with axial elongation and myopia development among schoolchildren aged 7 to 9 years. Sett ings and Design: Prospective study. Materials and Methods: Children in elementary schools without serious eye disorders were invited to participate. We measured cycloplegic refraction, corneal curvature, intraocular pressure, axial length, body height, and weight. Questionnaires about the children’s daily lifestyles, family members’ myopia and parents’ socio-demographic status were completed. The children were followed up every 6 months in a 3-year period. Statistical Analysis Used: Bivariate correlations, simple and multiple regression. Results: Eighty-eight children participated in this study. Forty-eight were myopic at the beginning of the study, and their myopia correlated with longer axial length and parental myopia (P = 0.015, 0.012). Sixty-fi ve children (74%) completed the study, and the rates of change per year were -0.43 ± 0.58 (mean + standard deviation) diopters in spherical equivalence, 0.32 ± 0.25 mm in axial length (AL), 5.73 ± 2.71 cm in body height, and 3.84 ± 2.23 kg in weight. The axial length change was positively correlated with the height change (P < 0.001). The myopia shift was correlated to axial length change (P = 0.000) but not correlated to height change. Using multiple regression test, near work was the only signifi cant risk factor for myopia progression (P = 0.022). Conclusions: Our study showed that body height increment was correlated to axial length elongation but not to myopia shift in children aged 7-9 years. Genetic factors such as parental myopia and body height had a possible infl uence on myopia development, and the environment factor as near work intensity was related to myopia progression.