Analysis Of Binocular Visual Function Before And After SMILE In Myopic Patients Of Different Ages

Purpose:To observe the changes of binocular visual function before and after Small incision lenticule extraction surgery(SMILE)in myopic patients of different ages and analyze the clinical significance,in order to provide some reference significance for surgical design and postoperative visual function training to improve visual symptoms such as visual fatigue.Method:Retrospective clinical study.Eighty-two patients(164 eyes)with myopia corrected by SMILE in the second hospital of Jilin University from March 2022 to September 2022 were included.The age ranged from 18 to 48 years(21.46±2.88years),and the preoperative spherical equivalent(SE)ranged from-9.38 D to-1.25D(-5.27±1.71D).Patients were divided into three groups according to their age:Group A: 37 patients(74 eyes),18≤ age <28 years old;Group B: 28 patients(56eyes),28≤ age <38 years old;Group C: 17 patients(34 eyes),38≤ age ≤48 years old.All patients underwent routine ophthalmological examination and binocular visual function examination before surgery,1 week,1 month and 3 months after surgery.Binocular visual function examination parameters mainly include accommodative function such as negative/positive relative accommodation(NRA/PRA),amplitude of accommodation(AMP),binocular cross-cylinder(BCC),binocular accommodative facility(BAF);vergence function such as accommodation convergence/accommation(AC/A)and negative/positive fusional vergence(NFV/PFV),distance lateral phoria / near lateral phoria(DLP/NLP),and filled in the questionnaire of asthenopia at the same time.The differences of data at different time points before and after surgery within the groups were performed by using repeated measurement analysis of variance and the differences of data among the groups were examined by using two-factor repeated measurement analysis of variance and LSD-t test.P< 0.05 was considered that the differences were statistically significant.To analyze and discuss the changes of binocular visual function in myopia patients of different ages before and after SMILE operation.Results:1.Comparison of accommodative function within groups: The changes of NRA and AMP in group A before and after operation were statistically significant(P <0.05).NRA increased after operation compared with preoperatively.AMP decreased 1week,increased 1 month after operation,and exceeded preoperative level 3 months after operation.The changes of NRA,PRA and AMP in group B before and after operation were statistically significant(P <0.05).NRA increased after operation compared with preoperatively.PRA decreased early after operation and increased 3months after operation;AMP decreased 1 week after operation,increased 1 month after operation,and even slightly exceeded the preoperative level 3 months after operation.The changes of AMP in group C before and after operation were statistically significant(P <0.05),which showed that AMP decreased early after operation and gradually exceeded the preoperative level 3 months after operation.There was no statistical difference in other parameters related to accommodative function within groups.2.Comparison of accommodative function among groups: There were significant statistical differences among three groups in the changes of PRA,AMP and BAF(F=6.073,P = 0.006;F =11.156,P = 0;F =3.332,P =0.048).The average value of PRA at each time point before and after surgery was group A > group B > group C,and the gap between group A and group B is smaller than that between group B and group C.It could be seen that the accommodative function of patients over 37 years old has decreased more significantly.Although PRA in the three groups all increased3 months after operation compared with the preoperative period,the change trends were slightly different.The PRA in group A increased 1 week after operation,while PRA in group B and group C decreased early after operation,then gradually increased,slightly exceeded 3 months after operation.The average value of AMP at each time point before and after operation was group A > group B > group C.The average value of BAF at each time point before and after operation was group A >group B > group C.However,the change trends in the three groups were slightly different.There was no statistical difference in other parameters related to accommodative function among groups.3.Comparison of vergence function within groups: There were significant differences in NPC break value and recovery value,far NFV break point and far PFV break point in group A before and after operation(P <0.05).The NPC break value and recovery value increased after operation.The far NFV break point and far PFV break point decreased after operation,and the two indexes gradually approached the normal value after operation.There were significant differences in NPC break value and recovery value,far PFV break point,near NFV blur point and break point,near PFV blur point 、break point and recovery point in group B before and after operation(P <0.05).The NPC break value and recovery value increased after operation.The far PFV break point,near NFV blur point and break point,near PFV blur point、break point and recovery point decreased after operation,and these indexes gradually approached the normal value after operation.There were significant differences in NPC recovery value,far PFV blur point and break point,near NFV break point,near PFV break point in group C before and after operation(P <0.05).The NPC recovery value increased after operation.The far PFV blur point and break point,near NFV break point and near PFV break point decreased after operation,and these indexes gradually approached the normal value 3 months after operation.4.Comparison of vergence function among groups: There were no significant differences in all of vergence function parameters(AC/A,NPC,NFV/PFV blur point,break point and recovery point)among the three groups.5.There were no significant statistical differences in intra-group and inter-group differences in visual fatigue scores before and after SMILE surgery.However,the change trends of the three groups were basically the same,that was,the average visual fatigue scores increased 1 week after operation,then decreased,and was lower than the preoperative level 3 months after operation.Conclusions:1.After SMILE surgery,myopic patients of different ages not noly had lower dioper and better vision,but also had better accommodative function,especially in the younger group.2.After SMILE surgery,the vergence function of myopia patients of different age groups improved to different degrees,but there was no statistical difference among the three groups,indicating that age may have little effect on the vergence function before and after operation.3.After SMILE surgery,the scores of visual fatigue increased 1 week after operation,then decreased,and were lower than the preoperative level 3 months after operation.Although there were no significant statistical differences within and among groups,it may still indicate that SMILE can improve the visual fatigue symptom in the long term.