High Altitude Retinal Hemorrhages Research Articles

Delayed high-altitude retinal hemorrhages in well-acclimatized lowlanders: A hidden risk unveiled.

High-altitude retinal hemorrhage (HARH), a frequent entity of high-altitude retinopathy (HAR), is associated with acute exposure to high altitudes (HAs) with rapid ascent. However, the delayed occurrence of HARH in well-acclimatized individuals has received less attention. This study explored the prevalence and characteristics of HARH in individuals who were acclimatized to HA for extended periods, aiming to elucidate the physiological responses of the retina to chronic hypoxic conditions. We conducted an observational cross-sectional study involving 1,457 male participants who had resided at altitudes above 3353 meters (11,000 ft) in the Himalayan region for more than three months. Patients who had ocular or systemic diseases affecting the retina, chronic retinotoxic medication use or smoking were excluded. Participants underwent comprehensive ophthalmic examination, including the best corrected visual acuity test, dilated fundus examination and photography. A total of 1,457 males were screened, and the mean age was 34 ± 2 years. Of all the participants screened, 12 (0.82%) had HAR, with all cases occurring at altitudes above 4267 meters (14,000 ft). Seventy-five percent (75%) of the HAR patients had retinal hemorrhage and venous dilatation. Macular involvement and cotton wool spots were observed in 34% and 25% of HAR patients, respectively. Only four participants had foveal involvement with significant visual impairment. Delayed HARH in acclimatized individuals underscores the importance of long-term ocular monitoring for those exposed to HA, despite acclimatization, to prevent and manage potential visual impairments.

High-altitude retinal hemorrhages and macular hemorrhage.

High-altitude retinal hemorrhages and macular hemorrhage.

An unusual case of high altitude-like retinopathy caused by anemia and thrombocytopenia at recreational altitude.

To report an unusual presentation of high altitude-like retinopathy at recreational altitude after chemotherapy-induced anemia and thrombocytopenia. Case report. A 43-year-old man undergoing chemotherapy for testicular cancer traveled to an altitude of 2,930 m and subsequently developed significant visual deficit in his right eye and was later diagnosed with bilateral severe high altitude-like retinopathy pathology with associated retinal hemorrhages. Altitude-related illnesses like high-altitude retinopathy result from rapid physiologic adaptation to altitude-induced hypoxia. These illnesses are typically experienced at altitudes above 3,000 m, with high-altitude retinal hemorrhages observed above 4,270 m. The patient participated in no strenuous physical activity but had severe enough retinal hypoxia from chemotherapy-induced anemia and thrombocytopenia that he experienced visually significant retinal hemorrhages. The occurrence of high-altitude retinopathy in such patients could portend the development of high-altitude cerebral edema at lower altitudes than traditionally reported and without exposure to known risk factors. Therefore, funduscopic examination should be performed on patients with anemia and thrombocytopenia who are complaining of decreased vision after traveling at high altitude.

High Altitude Retinal Hemorrhages–An Update

Retinal hemorrhages represent a common phenomenon in eyes of high altitude climbers. In this review, we present an update about this entity, with focus on its pathophysiology and practical implications. Due to their delayed appearance in the course of an expedition, retinal hemorrhages are not predictive when assessing the risk for life-threatening complications related to hypobaric hypoxia. Consequences for ocular health depend greatly on the extent and localization of retinal bleedings, but are generally mild and reversible in healthy eyes.

Delayed Appearance of High Altitude Retinal Hemorrhages

BackgroundRetinal hemorrhages have been described as a component of high altitude retinopathy (HAR) in association with altitude illness. In this prospective high altitude study, we aimed to gain new insights into the pathophysiology of HAR and explored whether HAR could be a valid early indicator of altitude illness.Methodology/Principal Findings28 mountaineers were randomly assigned to two ascent profiles during a research expedition to Mt. Muztagh Ata (7546 m/24,751 ft). Digital fundus photographs were taken prior to expedition at 490 m (1,607 ft), during expedition at 4497 m (14,750 ft = base camp), 5533 m (18,148 ft), 6265 m (20,549 ft), 6865 m (22,517 ft) and 4.5 months thereafter at 490 m. Number, size and time of occurrence of hemorrhages were recorded. Oxygen saturation (SpO2) and hematocrit were also assessed. 79% of all climbers exhibited retinal hemorrhages during the expedition. Number and area of retinal bleeding increased moderately to medium altitudes (6265 m). Most retinal hemorrhages were detected after return to base camp from a high altitude. No post-expeditional ophthalmic sequelae were detected. Significant negative (SpO2 Beta: −0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.Conclusions/SignificanceWhen closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes. The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding. Retinal hemorrhages should not be considered warning signs of impending severe altitude illness due to their delayed appearance.

Altitude Retinopathy on Mount Everest, 1989

The authors studied prospectively the incidence of and risk factors for high altitude retinal hemorrhages among 14 members of the 1989 American Everest Expedition. All subjects had comprehensive eye examinations and fundus photography performed at sea level before the expedition and again at the Mt. Everest Base Camp after 6 weeks of exposure to altitudes between 5300 and 8200 meters. Asymptomatic intraretinal hemorrhages were found in five eyes of four climbers. An additional eye of one of these climbers had a central retinal vein occlusion with vitreous hemorrhage, which reduced visual acuity to counting fingers. Higher baseline intraocular pressure and use of nonsteroidal anti-inflammatory drugs were found to be significant risk factors for development of altitude retinopathy.

Retinal vessel responses to exercise and hypoxia before and after high altitude acclimatisation.

Computerised microdensitometry was used to study diameter changes in 93 arterial and 91 venous vessel sites in the retinas of four mountain climbers before and after spending seven weeks in the Himalaya mountains. The vascular response to short-term strenuous exercise was measured at sea level, to acute hypoxia of simulated altitude of 15,000 ft (4,572 m) at rest, and to strenuous exercise while acutely exposed to the same hypoxic condition. Before the mountain exposure, retinal vessels constricted during exercise -1.9% (arteries); -3.3% (veins) and dilated in acute hypoxia 9.4% (arteries); 8.1% (veins). Superimposed exercise on hypoxic dilated arteries reduced the vasodilation (9.4% to 6%). After acclimatisation, the same physical work load at sea level constricted the arteries more (-5.4% vs -1.9%) but did not constrict the veins (0.2% vs -3.3%). Superimposed exercise on hypoxic dilated vessels, excessively dilated both arteries (8.4% vs 6.0%) and veins (13.7% vs 8.4%), compared to changes seen before the mountain sojourn. This study shows that physical conditioning and long adaptation to hypoxia, significantly change the vascular response of the retina to physical activity both in normal atmospheric conditions and during hypoxic stress. High altitude retinal hemorrhages (HARH) were present in one climber, and the study may indicate why HARH is seen often in young and physical well-trained subjects.

High-Altitude Retinal Hemorrhages

Skiers, hikers, and mountain climbers today can easily and rapidly attain high altitudes. Especially in climbing, competition to go higher and faster leads to greater exertion and less acclimatization. The syndromes of acute mountain sickness, high-altitude pulmonary edema, and cerebral edema are recognized, but many unanswered questions remain. Retinal hemorrhages and disc edema at high altitudes have been previously reported. Tschudi in 1839 1 noted ocular symptoms and signs (blurred vision, ocular pain, and conjunctival hemorrhages) at 12,000 ft in Peru. Sedan 2 found retinal hemorrhages in hypertensive subjects at 12,000 ft in 1938. Frayser et al, 3 in 1968, found a 37.5% incidence of retinal hemorrhages in climbers on Mt Logan (17,500 ft). Subsequent studies have found even higher frequencies. In this issue ofThe Journal, McFadden et al (p 581) are the first to report retinal cotton-wool spots at high altitudes. Their data show the increased incidence of

Effects of High Altitude on the Eyes

ABSTRACT The current issue of Archives of Ophthalmology publishes a trio of articles that deal with the effects of high altitude on the ocular system and brain. All three reports emphasize the prevalence of high-altitude retinal hemorrhages that disappear after return to low altitudes.Rennie and Morissey (93:395-400, 1975) had the opportunity to study the American expedition to Dhaulagiri (8,167 meters [26,795 ft]), a mountain in the Central Himalayas, the sixth highest mountain in the world and the highest ever climbed without the use of supplemental oxygen.The expedition included 15 experienced American climbers, all of whom were physically fit, and five Nepali Sherpas. Retinal photographs had been taken at sea level before the start of the climb and were repeated at high altitude after the climbers had undertaken quite strenuous exertion. All of the American climbers manifested ocular changes including vascular engorgement and tortuosity, plus retinal hemorrhages in five instances.

High altitude retinal hemorrhage.

The accessibility of high-altitude areas presents the risk of high altitude retinal hemorrhages (HARH). Four cases reported illustrate localized macular, diffuse, and familial incidence of HARH. Fluorescein angiography indicated no leakage, and a superficial retinal location of the hemorrhages. Marked retinal artery and vein dilation occurs. Ophthalmodynamometry showed retinal vascular hypertension in the presence of HARH. The complete resolution of hemorrhages occurs in most cases. Despite the return of visual acuity to normal, visual function studies indicate the persistance of defects.