The Search In The Rules Of Refractive Changes And Their Affect Factors Of Children's Hyperopia

[Objective] To study the rules of refractive changes in children with hyperopia and discuss their affect factors.[Methods] The refractions of 91 children (177 eyes) with hyperopia were followed for (4.40±1.34) years and the annual changes of the refraction were observed. The data was analyzed on the items of eyes, sex, age, hyperopia degree, astigmatism degree, with amblyopia and occlusion therapy or not and refractive correction degree to study their influence on emmetropization.[Results](1) During the follow-up, the average sphere component reduced (1.70 ±1.86) D totally and (0.38 ±0.46) D annually. It rose slightly at the early age, then reduced gradually in the following few years. And reached its peak at 2-3 years old, fell to the bottom at 8~9 years old.(2) There was 93.7% and 94.0% regular astigmatism for the first and the last visit. During the follow-up, the average cylinder component raised (0.27 ±0.97) D totally and ( 0.07 ± 0.24 ) D annually. The average cylinder component changed slightly with the age increasing, and a few astigmatism axises had changed.(3) During the follow-up, the average spherical equivalent reduced (1.71 ±1.55) D totally and (0.39±0.35) D annually. There was a slight rise at the early age and a rapid regression during 6-11 years old in the spherical equivalent. The sphere component and the cylinder component changed oppositely at the same time, and the sphere component had the greater change. The partial correlation coefficients of sphere component, cylinder component and spherical equivalent versus age were -0.009 (P=0.819) ,0.110 (P=0.005 ) and -0.012 ( P=0.767), and the partial correlation coefficient between sphere component and cylinder component was -0.157 (P=0.000) .(4) There was no significant difference in the spherical equivalent and its change between the two eyes of each child.(5) The average spherical equivalent of boy group was higher than girl group in the third visit (P<0.05) . There was no significant difference in the change of spherical equivalent at the same period between the two groups (P>0.05) , but the girl group had greater average annual change of spherical equivalent (P<0.05 ) .(6) The high power hyperopia group had greater annual regression in the first 3 following years and greater average annual regression in the whole follow-up than low and middle power hyperopia groups (P<0.01) , while the latter two groups had no significant difference (P>0.05) .(7) There was no significant difference in the annual change and the average annual change of spherical equivalent among the three groups with different astigmatism degree.(8) The average spherical equivalent of both eye-amblyopia group was higher than that of normal, visual acuity group (P<0.01) and amblyopic eye in the occlusion group (P<0.05), while its annual regression less than the normal visual acuity group.(9) There was no significant difference in the average spherical equivalent among the three groups with different refractive correction degree (P<0.01) .The more undercorrection, the higher spherical equivalent it was. Undercorrect >+1.25D group had greater refractive change than undercorrect +0.5D-+1.25D group in the third following year(P<0.05 )and its average annual refractive regression was greater than undercorrect ≤+0.5D group (P<0.05) .(10) Among the groups with same refractive correction degree, the spherical equivalent decreased with age increasing. The different correction degree groups at same age were significantly different in the average spherical equivalent. The refractive regression in groups with the same correction degree had significant difference among different ages (P<0.01) .(11) The average spherical equivalent of the three different correction degree groups had a slight fluctuate before 6 years old and a gradual regression after 7 years old, and the spherical equivalent of undercorrect ≥+2.0D group reduced fastest. The annual regression in spherical equivalent of undercorrect ≥+2.0D group was greater before 8 years old while the other two groups had greater annual regression after 7 years old. The undercorrect ≥+2.0D group had its regression peaks at 4~ 5 years and 8-9 years old, while complete correction or undercorrect <+1.0D group and undercorrect +1.0-+1.75D group had their sharpest regression during 7-10 years and 9-10 years old respectively.(12) The annual average spherical equivalent change was positively related with age and the group grade divided by refractive correction degree (partial correlation coefficients were 0.229 and 0.068 respectively) .[Conclusions](1) The hyperopia degree of children decreases with age increasing and it may rise slightly at the early age.(2) The astigmatism coexisting with hyperopia in children is mainly regular astigmatism. The cylinder component changes slightly with age increasing.(3) The sphere component and the cylinder component change oppositely at the same time, and the sphere component has the greater change. Therefore, the spherical equivalent has the similar change tendency to the sphere component with age increasing. The sphere component and the cylinder component are negatively related.(4) The high power hyperoipa group has greater annual average spherical equivalent regression than low and middle power hyperopia groups.(5) Refractive correction of different degree has effeect on the emmetropization of children with hyperopia. Moderate undercorrection is useful on the emmetropization of children with middle and high power hyperopia. The annual regression in spherical equivalent of undercorrect ≥+2.0D group is greater before 8 years old while the other two groups have greater annual regression after 7 years old.(6) The annual average spherical equivalent change of children with hyperopia is positively related with age and the group grade divided by refractive correction degree.