Spaceflight leads to brow elevation without affecting eyelid position: Study

Written By : Medha Baranwal |Medically Reviewed By : Dr. Kamal Kant Kohli Published On 2021-12-08T15:00:51+05:30 | Updated On 9 Dec 2021 3:56 PM IST

Spaceflight results in brow elevation without consistent elevation or depression of the eyelid. Los Angeles, CA: A recent study revealed that spaceflight although does not consistently alter upper eyelid position, it does lead to a significant elevation of brow position. In simpler words, gravity has a more pronounced effect on brow position than it does eyelid position. The study appears in the journal Ophthalmic Plastic and Reconstructive Surgery.

In the study, Justin Karlin, University of California, Los Angeles, CA, and colleagues aimed to describe the effect of spaceflight on upper eyelid and brow position.

For this purpose, the researchers collected images of astronauts on earth and in space from a National Aeronautics and Space Administration image library. The researchers obtained front-facing portraits captured within a 5-year period for each astronaut. At least 6 photos were collected per astronaut, 3 taken on earth, and 3 in zero gravity.

Measurements from the center of the pupil to the upper eyelid margin (MRD1) and the center of the pupil to the inferior eyebrow margin [pupil-to-brow (PTB)] were performed digitally for each image and averaged for each condition and each individual. Differences in mean MRD1 and PTB were assessed to illustrate the effects of zero gravity on eyelid and eyebrow position respectively.

The researchers in total retrieved one hundred and twelve photographs (55 earth, 57 space) from 18 astronauts (4 women, 14 men; mean age 45.9 years).

Based on the study, the researchers found the following:

Zero gravity resulted in a mean PTB increase of 3.7 mm but did not result in a significant change in MRD1.
Post hoc power analysis of the measured MRD1 difference was performed by simulation.
At an MRD1 difference of 0.5 mm, the probability of a type II error is 2.6%, equivalent to a beta power of 97.4%. Thus, the researchers were 97.4% confident that a difference in MRD of 0.5 mm or greater would be detected.

"While spaceflight led to a significant elevation of PTB, it did not consistently alter MRD1," wrote the authors. "As such, the brow and eyelid appear to be independently regulated with respect to gravitational changes."

Reference:

Karlin, Justin N. M.D., M.S.*; Farajzadeh, Justin M.S.†; Stacy, Stephanie C.Phil.‡; Esfandiari, Mahtash Ph.D.‡; Rootman, Daniel B. M.D., M.S.* The Effect of Zero Gravity on Eyelid and Brow Position, Ophthalmic Plastic and Reconstructive Surgery: November/December 2021 - Volume 37 - Issue 6 - p 592-594 doi: 10.1097/IOP.0000000000001961

spaceflighteyelideye browOphthalmic Plastic and Reconstructive Surgery

Source : Ophthalmic Plastic and Reconstructive Surgery

Medha Baranwal

MSc. Biotechnology

Medha Baranwal joined Medical Dialogues as an Editor in 2018 for Speciality Medical Dialogues. She covers several medical specialties including Cardiac Sciences, Dentistry, Diabetes and Endo, Diagnostics, ENT, Gastroenterology, Neurosciences, and Radiology. She has completed her Bachelors in Biomedical Sciences from DU and then pursued Masters in Biotechnology from Amity University. She has a working experience of 5 years in the field of medical research writing, scientific writing, content writing, and content management. She can be contacted at editorial@medicaldialogues.in. Contact no. 011-43720751

Dr. Kamal Kant Kohli

Dr Kamal Kant Kohli-MBBS, DTCD- a chest specialist with more than 30 years of practice and a flair for writing clinical articles, Dr Kamal Kant Kohli joined Medical Dialogues as a Chief Editor of Medical News. Besides writing articles, as an editor, he proofreads and verifies all the medical content published on Medical Dialogues including those coming from journals, studies,medical conferences,guidelines etc. Email: drkohli@medicaldialogues.in. Contact no. 011-43720751