Scene Context: Les's tears do not roll down his cheeks; instead, they gather over his eyes as large, salty spheres that distort his vision and must be physically wiped away.
Essence of the Phenomenon: In weightlessness, there is no gravitational force to pull liquid downwards. Instead, surface tension becomes the dominant physical force, causing the liquid to assume a spherical shape and "stick" to the surface of the eye.
Scientific Basis: On Earth, gravity overcomes the surface tension of a tear. In microgravity, a tear is secreted from the gland and, due to adhesion, stays in place. It forms a constantly growing water lens. This effect is well-documented by astronauts: a famous incident occurred with Chris Hadfield, when a water bubble in the eye could not drain away.
Current Limitations: The laws of fluid dynamics in microgravity are immutable. Water will always form spheres on the body's surface. If such a tear is not physically removed, it will significantly impair visibility and cause irritation.