The Investigation And Analysis About The Frequency Of Accommodative And Nonstrabismic Binocular Dysfunctions In A Population Of College Students

Objective:To investigate the frequency of accommodative and nonstrabismic binocular dysfunctions among college students, and analyze the feature of oculamotor parameter between symptomatic and asymptomatic college students.Methods:From a group of four year college students who were given a thorough eye examination,100 students were selected randomly who were correspond to the inclusion and exclusion criteria; Before tests all students in this study completed a15-question symptom questionnaire( Convergence Insufficiency Symptom Survey :CISS V-15),and then we divided them into two groups,symptomatic group which scores was 21 or higher and asymptomatic group which scores was beyond 21; For the college students above-mentioned,manifest refraction,worth4 dot,stereoacuity test,distant and near horizontal heterophoria,gradient AC/A ratio,positive and negative fusional vergences(distant and near),near Point of convergence(NPC),relative accommodation,lag of accommodation,amplitude of accommodation, monocular and binocular accommodation were measured;According to the diagnosis criteria for accommodative and convergence disorders,the tests above-mentioned were measured to diagnose the accommodative and nonstrabismic binocular dysfunctions, Using SPSS19.0 statistical software to analyze the frequency of convergencea and accommodative disorders, as well as compared with oculamotor parameter of symptomatic and asymptomatic students.Results:1 Mean age of the college students was 21.97±0.82 years, the frequency of symptoms between different genders were nearly the same(P>0.05);2 23% of the university students had specific binocular and accommodation symptoms, accommodative and/or nonstrabismic binocular dysfunctions were found in 24%of the students, the frequency of accommodative anomalies was 7%and 17%for nonstrabismic binocular dysfunctions. Accommodative excess(4%)and convergence insufficiency(8%)were the most common accommodation and convergence anomalies,respecttively.3 The frequency of symptomatic group with accommodation and convergence anomalies was higher than asymptomatic group(P<0.001);4 Comparison of oculamotor parameter of symptomatic and asymptomatic students :(1)Distance horizontal heterophoria: the average of distance heterophoria in the asymptomatic group was-0.96?±1.48 D, in the symptomatic group was-1.09?±3.67 D, the symptomatic group had more exophoria than the asymptomatic group, but there was no significant difference betweem them(P>0.05);(2) Near horizontal heterophoria:the average of near heterophoria in the asymptomatic group was-2.44 D ±2.61 D, in the symptomatic group was-3.87 D ±8.41 D, the symptomatic group had more exophoria than the asymptomatic group, but there was no significant difference betweem them(P>0.05);(3)Gradient AC/A ratio:the symptomatic group had lower AC/A ratio than the asymptomatic group(P<0.05);(4)Fusional vergences at distance:the symptomatic group had lower positive fusional vergences(blur\break\recovery point) and negative fusional vergences(break\recovery point) than the asymptomatic group, except positive fusional vergences(recovery point) and negative fusional vergences(break\recovery point),there was significant difference betweem them(P<0.05);(5) Fusional vergences at near:the symptomatic group had lower positive fusional vergences(blur\break\recovery point) than the asymptomatic group(P<0.001); negative fusional vergences(blur\break\recovery point) between different group were nearly the same(P>0.05);(6)Near Point of convergence(NPC): :the NPC(break\recovery point) in symptomatic group was father than the asymptomatic group,there was significant difference betweem them(P<0.05);(7)Amplitude of accommodation(AA):the AA in asymptomatic group had greater than the symptomatic group(P<0.001);(8) Relative accommodation:positive relative accommodation between different group were nearly the same(P>0.05);the symptomatic group had lower negative relative accommodation than the asymptomatic group(P<0.05);(9)Lag of accommodation:Lag of accommodation between different group were nearly the same(P>0.05);(10)Monocular and Binocular accommodation:both of them in asymptomatic group were lower than the symptomatic group(P<0.001);Conclusions:Accommodative and nonstrabismic binocular dysfunctions are prevalent in college students, ministry of Education and optometrists should pay more attention to it; Specific binocular and accommodative symptoms are potentially correlated with the decrease in the values of NPC、 gradient AC/A ratio,positive fusional vergences, negative relative accommodation 、 amplitude of accommodation, monocular and binocular accommodation;we should not only focus on vision correction, but also improve binocular visual function.