Altitude-Specific IOP Risks After Vitrectomy With Gas Tamponade: Modeling and Travel Guidance Based on Calculated Elevation Profiles.

Abstract

To develop a globally applicable, theoretical mathematical construct for predicting altitude-related intraocular pressure (IOP) elevation following pars plana vitrectomy (PPV) with intraocular gas tamponade, enabling personalized travel risk assessment through route-specific elevation profiling and bedside computational tools. Single-center retrospective observational case series integrated with computational modeling and clinical illustrative scenarios. Twelve patients (12 eyes) who underwent standard PPV with 14% C₃F₈ tamponade at Xinhua Hospital (altitude 0 m), failed to follow postoperative travel restrictions, and subsequently developed symptomatic IOP elevation during high-altitude travel (≥1000 m). A mathematical model was developed integrating Boyle-Mariotte's law with first-order gas absorption kinetics, incorporating surgical center altitude correction. Clinical application employs a binary safety threshold (ΔIOP ≤6 mm Hg: proceed; >6 mm Hg: defer). The framework was applied to 4 gases (14% C₃F₈, 16% C₂F₆, 20% SF₆, and 100% air). A Google Earth Pro-based elevation profiling protocol and web-based calculator were developed for bedside risk estimation. Predicted ΔIOP, binary safety determination, and minimum safe air travel intervals by gas type. Theoretical safety intervals varied by half-life: air travel (2400 m cabin) was safe after day 35 for C₃F₈, day 22 for both SF₆ and C₂F₆, and day 13 for air. The 12 cases illustrated clinical utility. This theoretical construct provides a reproducible, globally applicable binary decision-support tool for post-vitrectomy travel risk assessment. Route-specific elevation profiling and web-based calculation enable personalized bedside risk estimation.