Purpose: This study aims to comprehensively analyze ophthalmic manifestations in individuals from low-altitude (< 2,400 meters above sea level) areas who are exposed to high-altitude (HA) environments (3,500 meters above sea level), with a focus on anterior segment conditions and cranial nerve pathologies.
Methods: We conducted a prospective observational study of individuals at HA locations who presented with ocular complaints. Outcome parameters included age, gender, duration of exposure to HA, altitude of the location, duration of symptomatology, best corrected visual acuity (BCVA) at presentation, final BCVA post resolution, diagnosis based on signs and symptoms, treatment undertaken, time elapsed for resolution/hospital stay, associated laboratory findings, recurrences (if any), and need for de-induction/descent.
Results: Of the 2,043 patients who visited the eye outpatient department with ocular complaints, we included 130 lowlanders, with a mean age of 25.67 ± 5.14 years. The mean altitude was 3,560 meters above sea level. The mean duration of stay at HA ranged from 10 weeks to 21 weeks. The anterior segment manifestations that were observed included acute anterior uveitis (AAU) (n=12), Herpes Simplex Virus (HSV) Keratitis (n=30), HSV Keratitis with Iridocyclitis (n=4), Photokeratitis (n=30), Herpes Zoster Ophthalmicus (HZO) (n=10), facial nerve palsy with or without exposure keratopathy (n=24), non-resolving/chronic inflammatory conjunctivitis (n=20). Most cases responded well to treatment. However, 50% of AAU cases, 25% of HSV keratitis cases, 20% of HZO cases, and 33.33% of facial nerve palsy cases recurred within one year and therefore had to be de-inducted to a lower sea level.
Discussion: Delayed resolution was attributed to hypoxia-induced immune dysregulation, increased ultraviolet exposure, and frequent misdiagnosis of red eye at peripheral healthcare settings. High altitude appeared to exacerbate inflammatory and infectious ocular conditions and to precipitate sight-threatening posterior segment pathology.
Conclusion: This study provided a comprehensive understanding of ophthalmic challenges faced in HA environments. Awareness of these possible manifestations, along with accurate, timely diagnosis and, if necessary, referral to a specialist, is crucial to ensure optimal ocular health for individuals stationed at high altitudes.
Keywords: AAU = Acute Anterior Uveitis; BCVA = Best-Corrected Visual Acuity; CN = Cranial Nerve; CSCR = Central Serous Chorioretinopathy; FAF = Fundus Autofluorescence; HA = High Altitude; HAR = High-Altitude Retinopathy; HSV = Herpes Simplex Virus; HZO = Herpes Zoster Ophthalmicus; IOP = Intraocular Pressure; OCT = Optical Coherence Tomography; RD = Retinal Detachment; SD = Standard Deviation; UV = Ultraviolet; altitude; anterior segment involvement; duration of exposure; high altitude complications; high altitude ophthalmic manifestations; pO2 = Partial Pressure of Oxygen.
© 2026 The Authors.