Current Concepts on Aqueous Misdirection

Abstract

To review the current understanding of the pathophysiology and management of aqueous misdirection syndrome. Aqueous misdirection syndrome represents a spectrum of disorders that converge on a common pathway of increasing posterior segment pressure and secondary angle closure glaucoma. Although the etiology of aqueous misdirection remains unclear and is likely multifactorial, recent data supports choroidal expansion as an inciting event in the pathogenesis of the syndrome. As such, the term aqueous misdirection may be a misnomer. Some would argue that the use of terminology such as acute and chronic fluid misdirection may better characterize the full spectrum of the disease process as it is known to occur at varying time points from intraoperatively to years postoperatively. Chronic fluid misdirection most commonly occurs following incisional surgery for primary angle closure glaucoma but has also been associated with numerous laser and invasive ocular surgeries. Regardless of the mechanism, many patients require incisional surgery for complete resolution. Recent literature suggests that variants of anterior vitrectomy with irido-zonulo-hyaloidectomy offer comparable rates of success when compared to pars plana vitrectomy. Aqueous misdirection is a rare, and incompletely understood, form of secondary glaucoma characterized by diffuse shallowing of the anterior chamber in the presence of a patent iridotomy/iridectomy. It represents a spectrum of disorders that result in a cycle of increasing posterior segment pressure and secondary angle closure glaucoma that is notoriously refractory to medical intervention. Regardless of the mechanism, the syndrome can be well managed with incisional procedures that disrupt the anterior hyaloid face, debulk the vitreous, and establish an anterior-posterior communication either by a core or more complete anterior vitrectomy.