Clinical features and treatment of near-work-related acquired esotropia

AIM:To investigate the characteristics of near-workrelated esotropia and the clinical efficacy of botulinum toxin type A(BTXA)injection therapy on it.METHODS:A total of 107 patients aged 15-57y with near-work-related esotropia were taken as the BTXA-treated group,and 30 other peers without near-work-related esotropia were included in the control group.All participants were refractive corrected to analyse the clinical characteristics of near-work-related esotropia.All subjects were examined including Worth4 spot examination,stereoscopic vision,strabismus angle,accommodative convergence to accommodation ratio(AC/A),far and near positive and negative convergence,positive and negative fusion range,positive and negative relative accommodation.Clinical efficacy was evaluated at a period of 10mo follow-up.RESULTS:The distant and near stereopsis were found in 84.9%and 77.5%of patients in the BTXA-treated group,respectively.In the control group,all patients had distant and near stereopsis.The incidence of taking off one's glasses to see close objects was significantly higher in the BTXA-treated group than in the control group(P<0.05).The BTXA-treated group showed a smaller range of infusion(9.84±5.72)°than the control group(22.04±8.71)°(P<0.05).The near esotropia angle of the BTXA-treated group(17.08±11.98)△was significantly smaller than the distant esotropia angle(19.07±11.68)△(P<0.05).Ten months after injection,the diplopia and esotropia of most patients underwent improvements after treatment(P<0.05).CONCLUSION:This study reveals that the accommodation function and the habit of near work without wearing spectacles are associated with near-work-related esotropia,while the length of time for near work and the onset time are independent of near-work-related esotropia.Additionally,BTXA injection therapy plays a vital role in relieving diplopia and restoring eye position.