Study On The Horizontal Saccadic Velocity Of Preand Post-treatment In Divergence Insufficiency Patients

Objective The therapeutic effect of this disease was evaluated by comparing the characteristics of horizontal saccadic velocity with those of normal group and by combining with the analysis of the clinical features of divergence insufficiency,so as to improve the understanding of the disease.Methods It was a retrospective case series study.15 patients(30 eyes),who diagnosed and treated as "divergence insufficiency" in Tianjin Eye Hospital from October 2014 to March 2016,were summarized.The control group,defined as N group,was 16 normal subjects(32 eyes)selected randomly.Using Eyelink2000 to measure and record the date of saccade velocity of each eye when they abduct and adduct about 10° and 20°.Then the collection data were transformed into another format and imported into Metlab data processing software for offline filtering and processing.The peak velocities of the two groups were compared with those of the patient group on pre-treatment and post-treatment and combined with the clinical data pre-treatment and post-treatment,including the age of onset,skull MRI/CT examination,the average saccade peak velocities at different fixation angles both on pre-and post-treatment,to evaluate its therapeutic effect.Pre-treatment group was defined as P1,and the patient group at the final follow-up was defined as P2.All patients were followed up for 3 months to 2 years with an average of 7.3 months.All statistical analyzes were performed using SPSS 11.5 statistical software.Two independent samples t tests were performed among the groups and paired-samples t test in the group.Results 1.All the patients complained about symptomatic uncrossed diplopia only at distance fixation,and the direction of the complex visual distance was no significant difference.Although there were 6 cases of slow onset and 9 cases of acute onset,the symptoms were more stable.One of them had a history of Miller-Fisher syndrome,2 cases had a history of hypertension,and one case had a sleeping pills intaking history for 3 months.Besides neurological consultation by the same neuologist and head MRI,CT were no significant abnormalities reported.Lateral medial rectus muscle recession of 4.0 to 7.5 mm was performed on 14 patients.1 case was given to base-out prism management.2 cases had distance diplopia at the 6th week after treatment temporarily,but it disappeared when they wore glasses.3 cases apparented visual fatigue symptoms at near.Other patients' diplopia symptoms disappeared as well as obvious symptoms of eye discomfortable.The angle of esotropia,at distance,was from esotropia 14 PD to 40 PD but from 6PD to 25 PD at near(33cm)before treatment while chang extropia 4PD to esotropia 8PD at distance and extropia 8PD to esotropia 6PD at near(33cm)after treatment.The ratio of AC / A ranged from 0.7 to 4.0,with an average of 2.5 at pretreatment instead of 3.1(from 1.3 to 5.0)at posttreatment.The preoperative fusion divergence range was from 1° to 4°and its average was 2.5°.The preoperative fusional convergence was from 6° to 21°,with an average of 11.9° instead of the postoperative range of 10 ° to 24 ° with an average of 16.8°.The postoperative fusion divergence range was from 2 ° to 5 °,mean 3.0°.The postoperative near stereopsis was from 40 " to 800",with an average of 243.3 ",instead of the preoperative near stereopsis from 60 " to 3000 " but with an average of 733.3 ".2.The mean peak velocity in P1 group was lower than N group,but there was no significant difference between the two groups(P> 0.05).The average peak velocities of 20°adduction and 20°abduction beween P1 and P2 were statistically significant at pretreatment and posttreament,indicating that the saccadic velocity improved after treatment.Conclusion 1.The 10° and 20° abduction average peak velocities were different from that of normal subjects,but the difference was not statistically significant.The result support it that divergence insufficiency was a disease entity unrelated to the abducens paralysis.2.The surgery amount from 4.0 to 7.5mm of the lateral rectus resection has a good effect on correctting 14 PD to 40 PD esotropia at distance,eliminating diplopia and improving binocular vision function.3.The operation can improve the eye horizontal saccade velocity,and the effect is more obvious with the increase of the angle of abduction.