Dr. Abhishek Mandal, Ph.D.

Founder, Vision Science Academy, London, U.K.


Vision Science Academy Exclusive

Going into the space can bring a lot of changes in your body. Many of the astronauts return from space changed both in their outlook of life and health. The changes are not much obvious initially because they usually take time to develop. The longer the people are on a mission the more severe the effects of the weightlessness in space. These effects not only include muscle atrophy, skeletal deformities, and other systemic effects but eyesight abnormalities as well (Cucinotta et al., 2001).

One of the most notable of all adverse effects is the change in the visual acuity of the astronauts. Most astronauts complain of having poor vision after coming back to Earth. These results are more common in people who went into the space on missions spanning longer than two weeks. More than two-thirds of the astronauts who go up to the ISS (international space station) are bound to get this problem. This problem was found out after an extensive research undertaken by a team of radiologists, and was called the visual impairment and intracranial pressure syndrome (VIIP) (Wostyn & De Deyn, 2017).

How does Weightlessness decrease Visual Acuity?

The underlying mechanism of VIIP is not so complex to understand. In space, the blood pumped by the heart does not circulate much towards our legs, an effect which stems from a lower gravity. As a result, most of the blood moves into our heads. This increases the overall volume of intracranial fluid and causes an undue pressure on the optic nerve. Moreover, the increased intracranial pressure provides a continuous force on the back of the astronaut’s eyeballs which may even lead to inflammation (Mader et al., 2011).

Solutions for VIIP

Many solutions have been put forward to alleviate this problem, and help the astronauts perform better in space. The most important of them all is using a lower body negative pressure suit (LBNP). The main purpose of this suit is to prevent the upward shift of the body fluid towards the head. The suit provides an external negative pressure and helps move the blood back into the lower body. This halts the development of a raised intracranial pressure.

Another novel method for preventing VIIP is the use of negative pressure goggles. According to this idea, the vacuum in front of the eyes reduces some of the pressure and can counterbalance the pressure provided to the back of the eyes by raised ICP. This will lead to a significantly less strain on the eyes and improve the vision in space (Zhang & Hargens, 2018).


Currently, all the scientists are engaged in reducing the harmful effects of space on the human body. The task is arduous but will be completed soon. Neutralizing this problem will help unfold new paths to enhance the vision of humans further in space. New equipment like HUD goggles and glasses with built-in sensors are already in the pipeline. All these improvements will become mainstream and can even help humans roam Mars freely without causing any problem to the eyes.



Cucinotta, F. A., Manuel, F. K., Jones, J., Iszard, G., Murrey, J., Djojonegro, B., & Wear, M. (2001). Space Radiation and Cataracts in Astronauts. Radiation Research, 156(5), 460-466. doi:10.1667/0033-7587(2001)156[0460:SRACIA]2.0.CO;2 %J Radiation Research

Mader, T. H., Gibson, C. R., Pass, A. F., Kramer, L. A., Lee, A. G., Fogarty, J., . . . Polk, J. D. (2011). Optic Disc Edema, Globe Flattening, Choroidal Folds, and Hyperopic Shifts Observed in Astronauts after Long-duration Space Flight. Ophthalmology, 118(10), 2058-2069. doi:https://doi.org/10.1016/j.ophtha.2011.06.021

Wostyn, P., & De Deyn, P. P. (2017). Optic Nerve Sheath Distention as a Protective Mechanism Against the Visual Impairment and Intracranial Pressure Syndrome in Astronauts. Investigative Ophthalmology & Visual Science, 58(11), 4601-4602. doi:10.1167/iovs.17-22600 %J Investigative Ophthalmology & Visual Science

Zhang, L. F., & Hargens, A. R. (2018). Spaceflight-Induced Intracranial Hypertension and Visual Impairment: Pathophysiology and Countermeasures. Physiol Rev, 98(1), 59-87. doi:10.1152/physrev.00017.2016