Correlation Between Astigmatism Degree And Accommodation Function Of Myopia Children

Objective: To analyze the clinical characteristics of accommodative function of myopia children with different degrees of astigmatism,and to explore the correlation between astigmatism and accommodative and myopia occurrence and development.Methods: From June 2019 to June 2020,93 children(186 eyes)with low myopia who met the inclusion criteria were selected for the first visit in the ophthalmology clinic and optometry center of our hospital.According to the astigmatism degree of compound tropicamide mydriatic optometry at the first visit,38 cases were divided into non-astigmatism group(DC = 0 or DC <0.50D),29 cases were mild astigmatism group(0.50 D ≤ DC < 1.25D),and 26 cases were moderate astigmatism group(1.25 D ≤ DC < 3.00D).The spherical lens degree,eye axis and related eye adjustment parameters(positive and negative relative adjustment,adjustment response,adjustment amplitude and adjustment sensitivity)were measured at the initial diagnosis to statistically analyze the clinical characteristics of adjustment function of myopia children with different astigmatism degrees;The above indexes were reexamined at 3months and 6 months after wearing glasses,and compared with the initial diagnosis,so as to explore the correlation between astigmatism,adjustment and myopia.Results:1.spherical mirror:(1)first visit: there were significant differences among the groups at the first visit(P<0.01).among them,the spherical mirror power of non-astigmatism group was the lowest(-1.49±0.45D),and that of moderate astigmatism group was the highest(-2.13±0.41D).(2)Before and after wearing glasses: Compared with the first diagnosis,the non-astigmatic group increased after wearing glasses for 3months and 6 months.There was no significant difference between the two groups at different time points(P > 0.05).After wearing glasses for 3 months and 6 months,the spherical lenses in mild astigmatism group and moderate astigmatism group increased compared with those at the first visit,among which the growth amount in moderate astigmatism group was the highest at 6months(0.46±0.21D),and the difference between the two groups at different time points was statistically significant(P < 0.01).2.Eye axis:(1)First visit:There was a significant difference among the groups at the first visit(P< 0.01),among which the eye axis in the non-astigmatism group was the shortest(23.93±0.37mm)and the eye axis in the moderate astigmatism group was the longest(24.49±0.62mm).(2)before and after wearing glasses: the axial length of each group increased after wearing glasses for 3 months and 6 months compared with that at the first visit.after wearing glasses for 6 months,the growth of moderate astigmatism group was the most(0.28±0.37mm),while that of non-astigmatism group was the least(0.07±0.05mm).there was no significant difference between non-astigmatism group and mild astigmatism group at different time points before and after wearing glasses.There was significant difference between the moderate astigmatism groups at different time points(P<0.05).3.Positive relative adjustment:(1)First visit: The amount of positive relative adjustment at the first diagnosis was lower than the normal value,which was the highest in non-astigmatism group(-1.82±0.20D)and the lowest in moderate astigmatism group(-1.62±0.13D).(2)before and after wearing glasses: there were statistically significant differences in different time points before and after wearing glasses(P<0.01).compared with the first diagnosis,the improvement of each group was improved at 3months and 6 months,especially at 6 months,with the most increase in moderate astigmatism group(-0.51±0.18D)and the least increase in non-astigmatism group(-0.43±0.15D)4.Negative relative adjustment:(1)First visit: At the first visit,the negative relative adjustment values of each group were within the normal range,and the difference between each group was statistically significant(P<0.01).(2)Before and after wearing glasses:There was no significant difference between different time points before and after wearing glasses(P>0.05).5.Adjustment response:(1)First visit: The adjustment response of each group was greater than the normal value at the first visit,among which the adjustment lag in the moderate astigmatism group was the largest(1.26±0.25D),while the adjustment lag in the non-astigmatism group was the smallest(0.96±0.21D),and the difference was statistically significant(P<0.01).(2)before and after wearing glasses: the adjustment lag of each group decreased at 3 months and 6 months,and decreased significantly at 6 months compared with 3 months after wearing glasses,and decreased more obviously in astigmatism group than in non-astigmatism group.There were significant differences among the three groups at different time points before and after wearing glasses(P<0.01).6.Adjustment range:(1)First visit: The adjustment range of each group was lower than the minimum adjustment range of this age group at the first visit,there was no significant difference between each group(P>0.05).(2)Before and after wearing glasses:there was no significant difference between different time points in each group(P> 0.05).7.Adjustment sensitivity:(1)First visit: At the first visit,the adjustment sensitivity of each group was lower than the normal range,among which,the moderate astigmatism group was obviously lower than the non-astigmatism group and the mild astigmatism group,and the difference was statistically significant(P<0.01).(2)Before and after wearing glasses: the adjustment sensitivity of each group was improved after wearing glasses,especially in astigmatism group compared with non-astigmatism group,and there were significant differences among the three groups at different time points(P< 0.01).Conclusions:1.Myopia patients have the clinical characteristics of lagging adjustment,positive relative adjustment,decreasing adjustment amplitude and sensitivity,while negative relative adjustment is normal.2.The decrease of accommodation ability may be related to the existence of astigmatism.3.Astigmatism can promote the progression of low myopia in school-age children.4.Reasonable refractive correction can improve the adjustment function of myopia and astigmatism patients,including positive relative adjustment,adjustment response and adjustment sensitivity,but has no obvious effect on negative relative adjustment and adjustment amplitude.5.Reasonable refractive correction can indirectly delay the occurrence and development of low myopia in school-age children.