ABSTRACT
The effects of altitude on a series of ocular functions were studied on seven expedition members, all women aged 23-53 years, during the first ascent of the 6798-m peak Brigupanth in the Indian Himalayas. The only consistent change was a decrease in convergence amplitude. The amplitude of accommodation remained stable among the younger climbers, but decreased markedly among the older ones as higher altitudes were reached. There also appeared to be a lessened vascular reactivity to the hypoxia of altitude in the older members. Stereoscopic vision was unimpaired at all altitudes tested and extra-ocular muscle balance remained unaffected in all but two members who had an increase in their baseline phorias. Two of the summit climbers developed retinal hemorrhages. There was an average weight loss of 5.4 kg during the climb, but general health was good. Symptoms of acute mountain sickness were noted infrequently, and there were only moderate changes in the menstrual cycle.
Subject(s)
Altitude Sickness/complications , Hypoxia/complications , Vision Disorders/etiology , Adult , Age Factors , Altitude , Eye Diseases/etiology , Female , Humans , Hypoxia/physiopathology , Menstruation Disturbances/etiology , Middle Aged , MountaineeringABSTRACT
Six women mountaineers, 23-43 years of age, participated in a series of physiological tests prior to and during an expedition to Bhrigupanth (6798 m) in the Indian Himalayas. During a three-phase step test at sea level, carrying 0, 4.5, and 9.0 kg backpack weights, oxygen requirements represented 49.5-54.8% VO2 max. Recovery heart rates (HR) at 5-15 s were linearly related to exercise HR. At 4250 m, 5-15 s postexercise HR's were significantly higher than those at SL but returned to SL values after 3 min of rest. At 5000 m, HR's remained higher than those at SL throughout recovery. On returning to 4250 m after 3 weeks at higher altitudes, all postexercise HR's were back to SL levels. Supine HR's, higher at altitude than at SL during the ascent, returned to SL rates on return to 4250 m. Hemoglobin and hematocrit increased from 13.7 mg% and 42.4% at SL to 16.4 mg% and 52.6% after the climb. Resting blood pressure was significantly elevated at 4250 m during ascent but returned to SL values on the descent. During the cold pressor test, systolic pressure was unaffected by altitude; diastolic pressure increased less at altitude. While HR was unchanged at SL, a significant increase in HR was observed in postclimb CPT tests, even though perceived discomfort decreased.
Subject(s)
Acclimatization , Altitude , Cardiovascular Physiological Phenomena , Adult , Blood Pressure , Cold Temperature/adverse effects , Female , Heart Rate , Hematocrit , Hemoglobins/blood , Humans , Hypoxia/etiology , Hypoxia/physiopathology , Mountaineering , Oxygen ConsumptionABSTRACT
A traumatic phacocele in a previously injured eye is reported. Although subconjunctival dislocation of the lens is relatively rare, it should be considered in the differential diagnosis of an acquired, large conjunctival mass.
Subject(s)
Eye Diseases , Lens, Crystalline , Diagnosis, Differential , Eye Diseases/diagnosis , Eye Diseases/etiology , Eye Diseases/pathology , Eye Injuries/complications , Humans , Lens, Crystalline/pathology , Male , Middle AgedABSTRACT
Rabbits, irradiated by known cataractogenic levels of 2.45 GHz radiation at 5 cm, did not develop cataracts if kept under general hypothermia. Radiation-induced temperature elevation appears to be essential for the cataractogenic effect of microwaves.
