Comparative Study Of Combined Recession-Resection And Fenestration of Superior Rectus Muscle for Treatment of Dissociated Vertical Deviation

Dissociated vertical deviation (DVD) is a slow, disconjugate upward drift of the non-fixating eye, usually with abduction and excyclotorsion, that does not obey Hering's law . It is uncommon in the general population but develops in about half to 90% of children with infantile esotropia . Its cause is uncertain, probably a supranuclear vertical vergence disturbance after early disruption of binocular fusion, which explains its association with infantile esotropia . Non-surgical treatment suits small or well-controlled deviations: refractive correction, amblyopia therapy . Surgery is indicated when the deviation is frequently manifest or cosmetically unacceptable . When inferior oblique overaction coexists, anterior transposition of the inferior oblique is the procedure of choice . In isolated DVD, surgery aims mainly to weaken the superior rectus (SR). Conventional graded SR recession is the most widely used , but large deviations may need 10 mm or more and undercorrection is common . Recession-resection resects part of the muscle then recesses it by a greater amount, raising the weakening effect , while fenestration removes a central block of muscle and tendon near the insertion without sutures and is simpler and faster . Other options are a posterior fixation (Faden) suture and Y-splitting . The evidence is weak: a Cochrane review found the published studies small and retrospective and asked for randomized trials , and the only comparison of three SR techniques allocated patients by deviation size rather than at random . No trial has compared fenestration with recession-resection in children with DVD.