Hypertropia following insertion of inferiorly sited double-plate Molteno tubes

The use of double-plate Molteno tubes is well established in the management of intractable glaucoma, particularly in eyes that may have had previous surgical procedures, often involving the superior conjunctiva with subsequent subconjunctival scarring. As it is frequently the case that the area of least scarring is inferiorly, we have sited the tubes there but have found that, although this usually provides good control of intraocular pressure, successful drainage of aqueous has been associated with the development of hypertropia due to upward displacement of the globe by fluid encapsulated around the plates. We report a retrospective study of 16 eyes undergoing inferiorly sited double-plate Molteno tubes, in which 9 eyes developed significant hypertropia at a mean time after insertion of 3.5 months. Mean degree of hypertropia was 9.8 prism dioptres. The management of this complication is discussed.