Hypotropic dissociated vertical deviation: a unique form of dissociated strabismus complex

Abstract

Purpose: To report four cases of hypotropic dissociated vertical deviation (DVD) and to describe the clinical features of this rare disorder accompanied by a literature review.

Design: Interventional case series and literature review.

Methods: Four consecutive cases of hypotropic DVD and results of a literature review are presented. Data regarding age, visual acuity, laterality, amount of deviation, and type of surgery were analyzed.

Results: Collating data from previous reports with this case series identified a total of nine cases of DVD. Mean age at diagnosis was 26.1 years (range, two to 52 years). All except one patient had unilateral DVD. The average amount of hypotropia was 25.4 prism diopters. All but one patient had severe monocular vision deficits ranging from 6/16 to hand movements. The remaining patient had relatively good vision (6/7.5) and stereopsis (50 seconds of arc). Five patients had high myopia, and in three patients, the DVD was related to penetrating ocular injury. No cases of DVD were associated with congenital strabismus. A large recession of the inferior rectus muscle was performed in three patients and a combined recession-resection of the muscle was performed in another three patients. The results of both types of surgery were satisfactory.

Conclusions: Hypotropic DVD is mostly unilateral and commonly is associated with monocular visual deficits or high myopia. Although the nature of the intermittent slow downward ocular deviation is similar to that of hypertropic DVD, it should be considered to be a unique form of the dissociated strabismus complex. This rare condition can be corrected surgically by a large recession or a combined recession-resection of the inferior rectus muscle.