title: Tear Break-up Time in High Altitude Areas.
abstract: BACKGROUND
  In high altitude areas, patients report with irritation, redness and foreign body sensation in their eyes suggesting tear film abnormality due to low humidity and windy environmental conditions.
  
  
  METHODS
  Tear Break- up Time (TBUT) was studied in 100 subjects consisting of local population and those originally from plains residing in high altitude areas in Ladakh.
  
  
  RESULTS
  There were 24% individuals with TBUT of < 5 seconds, 30% between 6-10 seconds and 46% with TBUT of > 10 seconds. In symptomatic patients with TBUT of <5 seconds, eight cases had irritation of eyes, six foreign body sensation and two cases had pain, watering, irritation and redness of eyes. Pterygium was seen in 12 individuals and inter palpebral congestion in 4 cases.
  
  
  CONCLUSIONS
  A total of 24% cases showed abnormal (<5 seconds) TBUT. Abnormality of tear film in the presence of low humidity and windy condition with high ultraviolet radiation may lead to ocular discomfort and pterygium in these areas.
authors.affiliation: Professor of Ophthalmology, Manipal College of Medical Sciences, P.O.Box No.341, Pokhara, Nepal.
authors.forename: K N
authors.initials: KN
authors.lastname: Jha
keywords: High altitude areas (HAA); Tear Break-up Time (TBUT)