Vision – NSBRI http://nsbri.org National Space Biomedical Research Institute Wed, 23 Mar 2016 22:29:44 +0000 en-US hourly 1 https://wordpress.org/?v=5.5.9 Equinox Balance Goggles: The Effects of Local Orbital Pressure Changes on Intraocular Pressure http://nsbri.org/researches/equinox-balance-goggles-the-effects-of-local-orbital-pressure-changes-on-intraocular-pressure/ Wed, 23 Mar 2016 22:23:54 +0000 http://nsbri.org/?post_type=research&p=21972 Technology for controlling the pressure within the eye is currently limited to ophthalmic drops, laser treatments, or surgical procedures including microinvasive glaucoma stents and very invasive procedures that create an alternative drainage pathway in the eye. None of these methods can predict how much, if any, the pressure within the eye may be changed. The […]

The post Equinox Balance Goggles: The Effects of Local Orbital Pressure Changes on Intraocular Pressure appeared first on NSBRI.

]]> Technology for controlling the pressure within the eye is currently limited to ophthalmic drops, laser treatments, or surgical procedures including microinvasive glaucoma stents and very invasive procedures that create an alternative drainage pathway in the eye. None of these methods can predict how much, if any, the pressure within the eye may be changed. The Balance Goggles function by simply adding vacuum or pressure around the orbit of the eye, resulting in a normalization of the pressure differential in optic nerve diseases such as glaucoma, idiopathic intracranial hypertension (IIH), hypotony, and visual impairment and intraocular pressure (VIIP).

Dr. John Berdahl and colleagues are currently conducting a human research trial in the United States with a negative pressure application to the orbit of the eye with our product, Balance Goggles. The current study has been deemed Non-Significant Risk and is evaluating the safety of the Balance Goggles on up to 50 human patients with clinically normal eyes. The study will evaluate safety of wearing the Balance Goggles during a 30-minute time period with the negative pressure application on only one eye as compared to their control eye without a pressure application.

The post Equinox Balance Goggles: The Effects of Local Orbital Pressure Changes on Intraocular Pressure appeared first on NSBRI.

]]> Role of the Cranial Venous Circulation in Microgravity-Associated Visual Changes http://nsbri.org/researches/role-of-the-cranial-venous-circulation-in-microgravity-associated-visual-changes/ Tue, 15 Dec 2015 16:58:14 +0000 http://nsbri.org/researches/role-of-the-cranial-venous-circulation-in-microgravity-associated-visual-changes/ Upon entering microgravity, astronauts’ legs become thinner and their faces can look puffy, because of a shift of body fluids toward the head. This headward fluid shift affects the volume and pressure within veins in the head. These pressure and volume changes may underlie microgravity-associated visual symptoms because changes in pressures within the head can […]

The post Role of the Cranial Venous Circulation in Microgravity-Associated Visual Changes appeared first on NSBRI.

]]> Upon entering microgravity, astronauts’ legs become thinner and their faces can look puffy, because of a shift of body fluids toward the head. This headward fluid shift affects the volume and pressure within veins in the head. These pressure and volume changes may underlie microgravity-associated visual symptoms because changes in pressures within the head can also affect the eye.

But, not all astronauts experience changes to their vision in weightlessness. Differences in the anatomy, flow, and compliance of the veins in the head between individuals may explain this discrepancy. Our goal is to develop a numerical model of the cerebral venous circulation that can predict the effects of the fluid shifts. We will validate the model by using magnetic resonance imaging (MRI) of the head to measure changes in venous flow, venous volume, venous pressure, intracranial compliance, cerebrospinal fluid (CSF) volume and flow pulsatility during both fluid shifts and changes in body position. The likely anatomic differences that could alter the responses to a fluid shift will be identified. This model and supporting data will provide a way to develop hypotheses about how microgravity produces visual changes over time and may allow predictions about which subjects may be at risk for the visual deficits associated with microgravity.

The post Role of the Cranial Venous Circulation in Microgravity-Associated Visual Changes appeared first on NSBRI.

]]> Non-Invasive Monitoring of Intracranial Pressure (ICP) with Volumetric Ophthalmic Ultrasound http://nsbri.org/researches/non-invasive-monitoring-of-intracranial-pressure-icp-with-volumetric-ophthalmic-ultrasound/ Tue, 15 Dec 2015 16:58:12 +0000 http://nsbri.org/researches/non-invasive-monitoring-of-intracranial-pressure-icp-with-volumetric-ophthalmic-ultrasound/ The post Non-Invasive Monitoring of Intracranial Pressure (ICP) with Volumetric Ophthalmic Ultrasound appeared first on NSBRI.

]]> The post Non-Invasive Monitoring of Intracranial Pressure (ICP) with Volumetric Ophthalmic Ultrasound appeared first on NSBRI.

]]> e-Vision Electronic Adjustable Power Eyeglasses for Space and Earth http://nsbri.org/researches/e-vision-electronic-adjustable-power-eyeglasses-for-space-and-earth/ Wed, 27 Jan 2016 05:24:39 +0000 http://nsbri.org/?post_type=research&p=21406 Astronauts experience unpredictable vision changes during long periods of exposure to micro-gravity. Having the ability to change the optical power of their glasses will allow the astronaut to make vision adjustments as needed during the course of the mission rather than carrying a large assortment of various lenses with them into space. e-Vision Smart Optics […]

The post e-Vision Electronic Adjustable Power Eyeglasses for Space and Earth appeared first on NSBRI.

]]> Astronauts experience unpredictable vision changes during long periods of exposure to micro-gravity. Having the ability to change the optical power of their glasses will allow the astronaut to make vision adjustments as needed during the course of the mission rather than carrying a large assortment of various lenses with them into space.

e-Vision Smart Optics has developed electronic reading glasses that when switched off provide the user with their distance vision correction prescription and when switched on provide the user with their reading vision “plus” optical prescription. e-Vision has also developed electronic lenses for virtual and augmented reality systems that have an analog-tunable adjustable optical power. The objective of this project is to adapt the tunable lenses from the augmented and virtual reality uses for use in spectacle lenses so that the spectacle lenses may be used to adjust for vision changes in an almost unlimited number of adjustment steps rather than only an on/off mode as in the current spectacles.

The post e-Vision Electronic Adjustable Power Eyeglasses for Space and Earth appeared first on NSBRI.

]]> Microgravity Induced Visual Alterations and Intracranial Pressure (First Award Fellowship) http://nsbri.org/researches/microgravity-induced-visual-alterations-and-intracranial-pressure-first-award-fellowship/ Tue, 15 Dec 2015 16:58:14 +0000 http://nsbri.org/researches/microgravity-induced-visual-alterations-and-intracranial-pressure-first-award-fellowship/ Some long-duration astronauts have had diminished visual acuity during and after spaceflight. Serious visual impairment is not only problematic for an individual astronaut, but may be mission threatening for a long-duration crew. The mechanism(s) causing this problem remain largely unknown. The current working model is that it may be related to changes in intracranial pressure […]

The post Microgravity Induced Visual Alterations and Intracranial Pressure (First Award Fellowship) appeared first on NSBRI.

]]> Some long-duration astronauts have had diminished visual acuity during and after spaceflight. Serious visual impairment is not only problematic for an individual astronaut, but may be mission threatening for a long-duration crew. The mechanism(s) causing this problem remain largely unknown. The current working model is that it may be related to changes in intracranial pressure (ICP) due to fluid shifts in microgravity, perhaps exacerbated by small increases in the pCO2 or by exercise. However, only a few in-flight (ultrasound) and post-flight (MRI and lumbar puncture) observations support this contention. The only way to obtain this knowledge with certainty is to directly measure ICP during relevant changes in hydrostatic gradients. Importantly, these measures must be made in concert with an evaluation of inflow (arterial) and outflow (venous) pressures and flows to better understand intracranial hemodynamics in space.

The post Microgravity Induced Visual Alterations and Intracranial Pressure (First Award Fellowship) appeared first on NSBRI.

]]> STOP VIIP Study: Safe and Effective Countermeasures to Reduce Intracranial Pressure and Ameliorate VIIP in Astronauts http://nsbri.org/researches/stop-viip-study-safe-and-effective-countermeasures-to-reduce-intracranial-pressure-and-ameliorate-viip-in-astronauts/ Wed, 27 Jan 2016 04:37:55 +0000 http://nsbri.org/?post_type=research&p=21386 The visual impairment observed in many astronauts after long duration spaceflight aboard the International Space Station is considered the most important mission threatening medical problem identified in the last decade of the space program. Between 2012 and 2014, NASA and NSBRI spent $3-4 million/year investigating the clinical course and underlying mechanisms of this condition, termed […]

The post STOP VIIP Study: Safe and Effective Countermeasures to Reduce Intracranial Pressure and Ameliorate VIIP in Astronauts appeared first on NSBRI.

]]> The visual impairment observed in many astronauts after long duration spaceflight aboard the International Space Station is considered the most important mission threatening medical problem identified in the last decade of the space program. Between 2012 and 2014, NASA and NSBRI spent $3-4 million/year investigating the clinical course and underlying mechanisms of this condition, termed the Visual Impairment Intracranial Pressure syndrome (VIIP) because of its theoretical association with elevated intracranial pressure (ICP). During recently completed experiments funded by NSBRI, the investigators for this application performed the first invasive measures of intracranial pressure during acute (head down tilt bedrest, and parabolic flight) and chronic (24 hours HDT bedrest) changes in gravitational gradients simulating spaceflight in healthy humans and have made the following novel observations: 1) there is a large range of ICP experienced normally during changes in posture in daily life; 2) these changes occur within seconds of postural transients from upright to supine and then are stable over time in that position; 3) with acute assumption of simulated microgravity (HDT bedrest), ICP goes up slightly from the supine position, but over the next 24 hours, returns towards, and sometimes below the supine value because of spatial compensation within the brain; 4) during true microgravity (parabolic flight), the acute reduction in central venous pressure reduces cerebral outflow resistance and ICP decreases compared to the supine position, though remains above the upright position in 1G. Together, these results have led us to hypothesize that the VIIP syndrome is NOT due to a pathologically elevated ICP. However because there is not the usual reduction in ICP typically seen in the upright position on earth, the incessant, low level elevation in ICP (i.e., greater than upright, but less than supine) leads to adaptive changes in the eye which ultimately result in globe flattening, choroidal folds, and visual impairment.

This project will provide novel data about the efficacy of lower body negative pressure to mimic daily upright posture by intermittently lowering directly measured intracranial pressure (ICP) while in simulated microgravity. Examination of the associated inflow and outflow hemodynamics, accompanied by detailed assessment of localized intracranial fluid shifts and structural changes in the visual apparatus will establish the long-term safety and feasibility of this approach. This information is essential to establishing an appropriate method to simulate the upright posture and normal circadian variability in ICP over prolonged periods of time, with the objective of providing a robust countermeasure for visual impairment in astronauts.

The post STOP VIIP Study: Safe and Effective Countermeasures to Reduce Intracranial Pressure and Ameliorate VIIP in Astronauts appeared first on NSBRI.

]]> Effects of Microgravity on Intracranial Pressure http://nsbri.org/researches/effects-of-microgravity-on-intracranial-pressure/ Tue, 15 Dec 2015 16:58:12 +0000 http://nsbri.org/researches/effects-of-microgravity-on-intracranial-pressure/ The post Effects of Microgravity on Intracranial Pressure appeared first on NSBRI.

]]> The post Effects of Microgravity on Intracranial Pressure appeared first on NSBRI.

]]> Validation of a Cephalad Fluid Shift Countermeasure http://nsbri.org/researches/validation-of-a-cephalad-fluid-shift-countermeasure/ Wed, 27 Jan 2016 03:52:13 +0000 http://nsbri.org/?post_type=research&p=21374 This project directly addresses Critical Path Roadmap Risks and Questions regarding “Risk of Spaceflight-Induced Intracranial Hypertension/Vision Alterations,” and Integrated Research Plan Gap VIIP13: We need to identify preventative and treatment countermeasures to mitigate changes in ocular structure and function and intracranial pressure during spaceflight. Ophthalmic evaluations of astronauts after their 6-month missions to the International […]

The post Validation of a Cephalad Fluid Shift Countermeasure appeared first on NSBRI.

]]> This project directly addresses Critical Path Roadmap Risks and Questions regarding “Risk of Spaceflight-Induced Intracranial Hypertension/Vision Alterations,” and Integrated Research Plan Gap VIIP13: We need to identify preventative and treatment countermeasures to mitigate changes in ocular structure and function and intracranial pressure during spaceflight. Ophthalmic evaluations of astronauts after their 6-month missions to the International Space Station revealed unexpected vision problems. While there are many possible explanations for these vision problems in astronauts, elevated intracranial pressure due to a headward fluid shift during microgravity is proposed as the leading mechanism for the observed disc edema, globe flattening, choroidal folds, and hyperopic shifts. However, it is unclear if and how lower body fluid sequestration by an advanced thigh cuff device reduces ICP. These experiments will provide critical data required to objectively determine how an optimized thigh cuff could be incorporated into the NASA integrated physiological countermeasure suite. Therefore, the objective of this study is to determine the efficacy of a novel thigh cuff device to mitigate cephalad fluid shifts. In addition, this project will determine tissue pressure distribution applied by thigh cuffs in order to improve comfort, mobility, and efficacy of the countermeasure.

The post Validation of a Cephalad Fluid Shift Countermeasure appeared first on NSBRI.

]]> Prototype Testing for Noninvasive Determination of Intracranial Pressure http://nsbri.org/researches/prototype-testing-for-noninvasive-determination-of-intracranial-pressure/ Tue, 15 Dec 2015 16:57:41 +0000 http://nsbri.org/researches/prototype-testing-for-noninvasive-determination-of-intracranial-pressure/ On Earth, gravity exerts a downward force to keep fluids flowing to the lower body. Yet in space, fluids tend to redistribute toward the chest and head. As a consequence, some astronauts may experience brain edema (swelling due to an increase of fluid) and increased intracranial pressure. Neurosurgeons measure intracranial pressure by placing a device […]

The post Prototype Testing for Noninvasive Determination of Intracranial Pressure appeared first on NSBRI.

]]> On Earth, gravity exerts a downward force to keep fluids flowing to the lower body. Yet in space, fluids tend to redistribute toward the chest and head. As a consequence, some astronauts may experience brain edema (swelling due to an increase of fluid) and increased intracranial pressure. Neurosurgeons measure intracranial pressure by placing a device into several areas of the cranium. However, such a procedure is not possible on a space mission. Dr. Pierre D. Mourad is developing a simple, noninvasive method of monitoring intracranial pressure while in space.

The post Prototype Testing for Noninvasive Determination of Intracranial Pressure appeared first on NSBRI.

]]> Effects of Long Duration Spaceflight on Venous and Arterial Compliance in Astronauts http://nsbri.org/researches/effects-of-long-duration-spaceflight-on-venous-and-arterial-compliance-in-astronauts/ Tue, 15 Dec 2015 16:58:14 +0000 http://nsbri.org/researches/effects-of-long-duration-spaceflight-on-venous-and-arterial-compliance-in-astronauts/ Visual impairment and intracranial pressure (VIIP) is a space flight-associated medical condition affecting at least a third of American astronauts who have flown International Space Station (ISS) missions. VIIP is defined primarily by visual acuity deficits and anatomical changes to eye structures. In some astronauts, eye-related changes do not revert back to the pre-flight state […]

The post Effects of Long Duration Spaceflight on Venous and Arterial Compliance in Astronauts appeared first on NSBRI.

]]> Visual impairment and intracranial pressure (VIIP) is a space flight-associated medical condition affecting at least a third of American astronauts who have flown International Space Station (ISS) missions. VIIP is defined primarily by visual acuity deficits and anatomical changes to eye structures. In some astronauts, eye-related changes do not revert back to the pre-flight state upon return to earth. Dr. Platts will be studying some of the possible causes for this syndrome. This will be achieved by reviewing previous astronaut data for factors that may predispose astronauts to higher rates of developing this syndrome or greater severity of symptoms. Additionally, we will conduct 3 separate experiments involving astronauts and bed rest subjects that will characterize vessels in the head and neck and measure the effects of the experimental conditions on ocular structures and function.

The post Effects of Long Duration Spaceflight on Venous and Arterial Compliance in Astronauts appeared first on NSBRI.

]]>