Strabismus/Diplopia After Glaucoma Drainage Devices: A Systematic Review of Method-Dependent Rates, Time Courses, Risk Factors, and Managements
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Purpose
To synthesize method-dependent rates, time courses, risk factors, mechanisms, and management of strabismus/diplopia after glaucoma drainage device (GDD) surgery.
Methods
PRISMA-2020 systematic review (PROSPERO CRD420251110465) across seven databases to 21 July 2025, including randomized trials, cohorts, and case series. Outcomes were prespecified: incidence (early ≤3 months; late ≥12 months), visit-prevalence by standardized orthoptics or patient-reported outcome measures (PROMs), and chart-documented postoperative occurrence. Narrative synthesis followed SWiM guidance. Denominators were per patient for diplopia/strabismus and per eye for motility limitation.
Results
Ninety-one studies (11,681 patients; 12,068 eyes) met criteria. Onset clustered early (median ≈6 weeks), followed by two trajectories, many cases remitted with capsule remodeling; a minority persisted with restrictive tethering. Apparent rates varied by ascertainment and unit: persistent diplopia was 0–5% in contemporary chart-ascertained cohorts, ∼5% at 1 year and ∼4% at 5 years in standardized-orthoptic trials, and up to ∼23% at 1 year in PROM studies. Surgical anatomy and tissue planes outweighed device family or nominal plate size: inferior placement increased early strabismus (≈21% ≤3 months vs 0% with superior placement), and pars plana entry showed higher diplopia than anterior-chamber entry in matched cohorts. Mechanism was predominantly restrictive (posterior-fixation–like) from capsule–muscle coupling. Management mirrored the natural history: early symptoms often resolved with observation/prisms; persistent, clearly restrictive deviations benefited from capsule-aware adhesiolysis with limited, targeted rectus surgery; device revision/explant was uncommon.
Conclusion
Post-GDD motility morbidity is chiefly restrictive and measurement-dependent. Reports should separate incidence from visit-prevalence, distinguish any from persistent diplopia, and use per-patient denominators for diplopia/strabismus and per-eye for motility limitation. Future trials should standardize orthoptic endpoints, pair PROMs with imaging of the plate–muscle interface, and power for motility outcomes alongside IOP.
