Comparison of conventional and Hang-back methods of inferior oblique recession in V-pattern strabismus with inferior oblique overaction

AIM:To compare outcomes of conventional and Hangback methods of inferior oblique(IO)recession in V-pattern strabismus with inferior oblique overaction(IOOA).METHODS:Comparative randomized study was conducted consisting of 50 patients,age 6 to 35 y having V-pattern strabismus[>15 prism diopter(PD)]with IOOA.They were divided equally in two groups and underwent IO recession,group A by conventional method and group B by Hang-back method.Parameters evaluated were reduction in V-pattern and IOOA,shift in torsion,improvement in binocular status.Success was a residual V-pattern of less than 10 PD at 1 y of follow up.RESULTS:The mean V-pattern preoperatively and postoperatively at 1 y was 24±5.4 PD and 4.2±3.51 PD in group A and 23.44±6.44 PD and 5.76±3.8 PD in group B respectively.The mean reduction in V-pattern was 20±6.78 PD in group A and 18.2±5.48 PD in group B.The mean correction of IOOA was 18.48±3.13 PD in group A and 16±2.93 PD in group B.Mean shift in extorsion was 3.08±1.8 degree in group A and 3.72±2.14 degree in group B.CONCLUSION:Both the procedures achieve a significant and comparable reduction in V-pattern and IOOA.Hang-back recession being a landmark free surgery eliminates the need for intrascleral suturing thereby reducing the risk of scleral perforation with possible postoperative adjustment of muscle.It may be considered as a good alternative for IO recession in patients of V-pattern strabismus with mild to moderate amount of IOOA.

Effectiveness of modified inferior oblique muscle belly transposition for V-pattern exotropia combined with mild to moderate inferior oblique muscle overaction

AIM:To investigate the effectiveness of a modified inferior oblique muscle belly transposition for treatment of V-pattern exotropia combined with mild to moderate inferior oblique muscle overaction.METHODS:Thirteen cases(23 affected eyes)of V-pattern exotropia with inferior oblique muscle overaction(+or++)who underwent the modified inferior oblique muscle belly transposition procedure were retrospectively reviewed.The amount of V-pattern,grade of inferior oblique overaction,degree of vertical strabismus,abnormal head posture,and the fovea-disc angle were evaluated before and after surgery.RESULTS:The V-pattern was corrected in all cases,and the amount of V-pattern reduced by 17.85±5.13 prism diopter(PD)on average(t=16.07,P<0.001).The surgical cure rate for mild to moderate inferior oblique muscle overaction was 87.0%(20/23).The degree of the foveadisc angle has a mean reduction of 5.45°±2.87°(t=3.95,P=0.003)after surgery.The mean vertical deviation in 5 cases with a small-angle hypertropia(5.23±3.06 PD)in the primary position reduced by 3.15±1.86 PD(t=6.10,P<0.001).No serious complications were observed.CONCLUSION:The modified inferior oblique muscle belly transposition procedure can effectively treat mild to moderate inferior oblique overaction and relieve the V-pattern,which is safe and easy to perform.