How much screen time is too much?
There's no universal safe threshold — it depends heavily on how the time is structured. Seven hours of screen time with regular breaks and good ergonomics is far less harmful than four hours of unbroken, close-up, poorly lit screen use. Total time matters less than session length, break frequency, and whether screens are used before sleep.
Why unbroken sessions are the real problem
During a continuous screen session, blink rate falls steadily, tear film breaks down progressively, and the focusing muscles accumulate fatigue without release. After 90–120 minutes of unbroken focus, this damage is significant. A 5-minute break resets most of it. The same total screen hours split into shorter sessions with real breaks produces dramatically less strain.
Screens before sleep: the compounding effect
Evening screen use is often the most underappreciated contributor to eye strain — not because of what it does in the moment, but because it disrupts sleep quality. Eyes that haven't recovered overnight start the next day at a disadvantage. People who report persistent, worsening eye strain despite "not that much screen time" often have poor sleep as the compounding factor.