It is important to recognize that videos cannot accurately represent what the human eye perceives in real-life scenarios. The human eye operates very differently from a video camera, exhibiting greater flexibility in handling aspects such as refresh rates, resolutions, brightness, and color balance. Therefore, the only true way to assess a system’s performance is through direct interaction; it won’t take weeks to identify issues that might impact your experience.
For instance, I can record a video of my MacBook Air showing a flicker that originates from a mismatch in refresh rates with my iPhone. While the video might appear poor, I haven’t noticed any flicker while using the laptop for three years. This discussion isn’t new, but it warrants a response.
Some argue that videos vividly illustrate what the eyes see, making it easier to understand phenomena that may not be apparent in real-time. Our biology processes light signals rapidly; when a display flickers, it can be understood as a mechanism for adjusting brightness using pulse-width modulation (PWM). It’s noteworthy that many laptops are specifically designed to avoid PWM for brightness control given its known adverse effects on sensitivity.
As a result, individuals who are sensitive to PWM should steer clear of Apple laptops, unless they are paired with an external non-PWM display. This hardware design constraint is prevalent in many PC laptops and even smartphones. I have personally experienced migraines linked to PWM displays.
After using an iMac that caused significant eye strain, I realized that the headaches subsided once I stopped using it. Consequently, my M1 Pro MacBook Pro remains unused unless connected to an external monitor, as I experienced discomfort after just three days of use. In my opinion, electronic devices utilizing PWM should carry warnings about their potential health impacts.
The mechanism at play is that the eye adjusts its light intake by dilating and constricting pupils. When a display flickers excessively, it causes pupil dilation that can lead to discomfort and potential damage over time. This issue has persisted with various devices since 2012, necessitating careful selection of laptops to avoid such problems.
Ultimately, the only viable solution for those affected is to use an external display that does not rely on PWM. Anything else could be merely a placebo, failing to address the core of the issue.
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