A young trekker’s adventure in the Leh-Ladakh region took a sudden, alarming turn when he experienced painless, sudden vision loss. Rapidly ascending to 15,000 feet, the trekker was diagnosed with Central Retinal Artery Occlusion (CRAO) at a nearby army base hospital – a rare condition where blood supply to the retina is abruptly blocked, potentially causing permanent vision impairment.
The trekker, whose identity has been kept private, embarked on a high-altitude trek in the scenic but treacherous Himalayan region. Within hours of reaching 15,000 feet, he reported sudden visual loss without pain. Immediate evaluation at the army base hospital confirmed CRAO.
Blood tests revealed erythrocytosis, an abnormal increase in red blood cell count, and raised homocysteine levels – both factors that can exacerbate vascular complications in extreme environments. Despite immediate interventions, including digital massage and anterior chamber paracentesis (procedures aimed at relieving intraocular pressure and restoring retinal blood flow), the patient’s vision only partially improved to 6/60, leaving significant visual impairment.
Medical experts attribute such cases to High Altitude Retinopathy (HAR) – a condition triggered by rapid ascent to high elevations. At these heights, low oxygen levels and pressure fluctuations can compromise the integrity of retinal blood vessels. Secondary complications, such as erythrocytosis, can further impede blood flow, occasionally culminating in serious outcomes like CRAO.
A landmark study by Wiedman and Tabin (1999) on climbers ascending above 25,000 feet reported that nearly all participants developed signs of HAR, confirming that rapid ascent poses a real threat to retinal health.
Dr. Ashish Markan, a vitreoretinal surgeon from AIIMS Delhi, who shared the case on Instagram, explained:
The likely cause is High Altitude Retinopathy – damage to retinal vessels secondary to rapid ascent and changes in blood composition. Diabetic retinopathy and other microvascular conditions can further increase vulnerability.
Dr. Ashish Markan, Vitreoretinal surgeon, MD (AIIMS, Delhi), MCh (VR, PGI), FRCS (UK), FICO (UK), FAICO (VR and Uvea), DNB
With Leh-Ladakh receiving over millions of visitors annually, Dr. Markan emphasized precautionary measures to reduce the risk of HAR:
Ascend gradually: Limit altitude gain to no more than 500 meters per day above 3,000 meters.
Stay hydrated: Consume 4–5 liters of water daily to prevent blood thickening.
Monitor for symptoms: Sudden blurred vision, headaches, or dizziness should trigger immediate rest and evaluation.
Seek prompt medical care: Army bases in the region have 24/7 eye units capable of managing acute retinal emergencies.
References:
Wiedman M, Tabin GC. High-altitude retinopathy and altitude illness. Ophthalmology. 1999 Oct;106(10):1924–1926; discussion 1927. doi:10.1016/S0161-6420(99)90402-5. PMID: 105
(Rh/VK/MSM)
