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Related Experiment Video

Updated: Jun 1, 2026

Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile

Published on: September 20, 2024

Determining spherical lens correction for astronaut training underwater.

Jason Porter¹, C Robert Gibson, Samuel Strauss

¹College of Optometry, University of Houston, Houston, Texas 77204-2020, USA. jporter@optometry.uh.edu

Optometry and Vision Science : Official Publication of the American Academy of Optometry

|May 31, 2011

Summary

Astronauts training underwater need precise vision correction. A new model accurately predicts the necessary spectacle lens power, accounting for refractive changes caused by replica space suit helmets submerged in water.

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Area of Science:

Optics
Human Factors Engineering
Space Medicine

Background:

Astronauts require precise vision correction for underwater training.
Replica space suit helmets with curved visors induce significant refractive power when submerged.
This optical distortion necessitates accurate compensation for effective training.

Purpose of the Study:

To develop a predictive model for spectacle lens correction for astronauts during underwater training.
To accurately determine the spherical lens power needed to counteract the refractive effects of submerged replica space suit helmets.

Main Methods:

Measured anterior surface powers and thicknesses of helmet visors.
Analyzed visor impact on refractive power using thick lens calculations and Zemax optical design software.
Developed a geometrical optics model to predict underwater spherical correction based on helmet-induced power and air correction.

Main Results:

Submerged helmet visors induced a total power of -2.737 D.
A linear relationship was found: Underwater Correction (FW) = Air Correction (FAir) + 2.356 D.
The model demonstrated high accuracy, with 70% of eyes showing <0.25 D difference from actual correction (r=0.971).

Conclusions:

A validated model accurately calculates required underwater spectacle lens correction for astronauts.
The model can be generalized for determining spectacle correction behind other underwater masks.
This facilitates improved visual acuity and safety during astronaut training simulations.