A Guide to Eye Use during Long Online Classes: Three Dimensions: Devices, Lighting, and Habits

01. Habit dimension: Rhythm comes first

The 20-20-20 rule: Every 20 minutes, look at a distance of 6 meters for more than 20 seconds. During the break, leave the screen, blink consciously and completely, and keep a viewing distance of 50 to 70 centimeters. The evidence level of these zero-cost interventions is higher than that of all peripheral products.

Observation indicators available to parents: Children rubbing their eyes, blinking frequently, and leaning close to the screen are early signals for regulating tension.

02. Light dimension: Don't look at the illuminated screen in a completely dark room

The difference between ambient light and screen brightness is an important source of visual load: Turn on a low-color-temperature background light at night to keep the brightness ratio of the screen to the environment within an adaptable range. The top of the screen is slightly lower than the line of sight to reduce the exposure of the eye surface.

Natural light during the day is a relatively ideal environment - two hours outdoors has a relatively high level of evidence for myopia prevention and control, but be careful to avoid direct sunlight on the screen causing mirror glare.

03. Device dimension: Do subtraction rather than addition

Screen parameters: Adjust the brightness to match the environment (white paper test: The brightness of the white image should be close to that of the paper), and enable night view to lower the color temperature at night. At the device level, reflection is a more common source of stimulation than blue light: specular reflection forces the eyes to repeatedly adapt, and low-reflection solutions (AR coating) have fewer side effects than dye filtration.

The final calibration expectation: No film product can prevent myopia or solve the problem of flicker. What they optimize is the aspect of viewing comfort.