Resolution of diabetic macular oedema following high altitude exercise

Averous, K.; Erginay, Ali; Timsit, José; Haouchine, B.; Gaudric, Alain; Massin, Pascale

doi:10.1111/j.1600-0420.2006.00701.x

Cited by 10 publications

(3 citation statements)

References 8 publications

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“…Resolution of macula oedema and reduced retinal thickness has been reported in a diabetic patient during HBO therapy. 35 No changes in intraocular pressure or axial length of the eye occurred in these patients after treatment, which is in line with results reported in other studies using the similar HBO treatment protocol. 4,5,12 A limitation of the study is that posterior surface of the lens appeared visible only in one third of the patients because of restricted dilation of the pupil.…”

Section: Discussionsupporting

confidence: 91%

Myopic Shift during Hyperbaric Oxygenation Attributed to Lens Index Changes

Evanger¹,

Pierscionek²,

Vaagbø³

et al. 2015

Optometry and Vision Science

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Section: Discussionsupporting

confidence: 91%

Myopic Shift during Hyperbaric Oxygenation Attributed to Lens Index Changes

Evanger¹,

Pierscionek²,

Vaagbø³

et al. 2015

Optometry and Vision Science

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“…Another way to reduce the hydrostatic pressure in the microcirculation is to constrict the arterioles. This may be done simply by breathing oxygen-enriched air which has been shown to constrict retinal blood vessels and reduce diabetic macular edema (111)(112)(113)(114). Retinal oxygenation may also be improved by scattered laser treatment, which destroys a part of the retina and thereby reduces its oxygen consumption (17,22,(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50).…”

Section: How Do We Treat Edema?mentioning

confidence: 97%

Physiology of vitreous surgery

Stefánsson

2008

Graefes Arch Clin Exp Ophthalmol

256

198

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Vitreous surgery has various physiological and clinical consequences, both beneficial and harmful. Vitrectomy reduces the risk of retinal neovascularization, while increasing the risk of iris neovascularization, reduces macular edema and stimulates cataract formation. These clinical consequences may be understood with the help of classical laws of physics and physiology. The laws of Fick, Stokes-Einstein and Hagen-Poiseuille state that molecular transport by diffusion or convection is inversely related to the viscosity of the medium. When the vitreous gel is replaced with less viscous saline, the transport of all molecules, including oxygen and cytokines, is facilitated. Oxygen transport to ischemic retinal areas is improved, as is clearance of VEGF and other cytokines from these areas, thus reducing edema and neovascularization. At the same time, oxygen is transported faster down a concentration gradient from the anterior to the posterior segment, while VEGF moves in the opposite direction, making the anterior segment less oxygenated and with more VEGF, stimulating iris neovascularization. Silicone oil is the exception that proves the rule: it is more viscous than vitreous humour, re-establishes the transport barrier to oxygen and VEGF, and reduces the risk for iris neovascularization in the vitrectomized-lentectomized eye. Modern vitreous surgery involves a variety of treatment options in addition to vitrectomy itself, such as photocoagulation, anti-VEGF drugs, intravitreal steroids and release of vitreoretinal traction. A full understanding of these treatment modalities allows sensible combination of treatment options. Retinal photocoagulation has repeatedly been shown to improve retinal oxygenation, as does vitrectomy. Oxygen naturally reduces VEGF production and improves retinal hemodynamics. The VEGF-lowering effect of photocoagulation and vitrectomy can be augmented with anti-VEGF drugs and the permeability effect of VEGF reduced with corticosteroids. Starling's law explains vasogenic edema, which is controlled by osmotic and hydrostatic gradients between vessel and tissue. It explains the effect of VEGF-induced vascular permeability changes on plasma protein leakage and the osmotic gradient between vessel and tissue. At the same time, it takes into account hemodynamic changes that affect the hydrostatic gradient. This includes the influence of arterial blood pressure, and the effect oxygen (laser treatment) has in constricting retinal arterioles, increasing their resistance, and thus reducing the hydrostatic pressure in the microcirculation. Reduced capillary hydrostatic pressure and increased osmotic gradient reduce water fluxes from vessel to tissue and reduce edema. Finally, Newton's third law explains that vitreoretinal traction decreases hydrostatic tissue pressure in the retina, increases the pressure gradient between vessel and tissue, and stimulates water fluxes from vessel into tissue, leading to edema.

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“…Although some studies have suggested the beneficial effects of living at HA on glucose homeostasis, the relationship between HA and DR remains unclear owing to multiple factors and potential confounders, such as varying altitudes of the investigated population, duration of exposure to HA, genetic backgrounds, living conditions, dietary habits, and physiological adaptation. Table 1 summarizes the main findings of previous studies [9][10][11][12][13][14][15] that explored the impact of HA on DR. This review aimed to comprehensively explore the impact of HA exposure on DR, encompassing genetic adaptations, changes in glucose homeostasis, and related factors.…”

Section: Introductionmentioning

confidence: 99%

High-Altitude Exposure and Diabetic Retinopathy: Unveiling the Impact and Mechanisms of Alleviation

Gong,

Zhou,

Gama

et al. 2023

Ophthalmic Res

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High altitude (HA) is an extremely challenging environment for millions of people who either travel to HA regions or inhabit there permanently. Significant progress has been made over the past decades in the understanding of physiological adaptations in HA conditions, and recently, more studies regarding its influence on metabolic disease have been published. However, the effect of HA on diabetic retinopathy (DR), the leading cause of blindness, remains unclear. The present article provides an overview of the changes in the principal physiology and clinical characteristics related to DR after HA exposure. Despite conflicting evidence, this review synthesizes the available studies and explores the potential mechanisms, such as genetic adaptations, glucose homeostasis, and related physiological changes, by which long-term exposure to HA may alleviate the progression of DR. By shedding light on this complex relationship, it also provides insights into the interplay between HA and DR, offering valuable implications for clinical practice and further research.

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Resolution of diabetic macular oedema following high altitude exercise

Cited by 10 publications

References 8 publications

Myopic Shift during Hyperbaric Oxygenation Attributed to Lens Index Changes

Myopic Shift during Hyperbaric Oxygenation Attributed to Lens Index Changes

Physiology of vitreous surgery

High-Altitude Exposure and Diabetic Retinopathy: Unveiling the Impact and Mechanisms of Alleviation

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