This is mostly empiric information I have compiled over several years from various sources, and from my own day-to-day experience.

While there does not seem to be a perfect – scientifically proven – screen properties to keep your eyes healthy, there are some worthy qualitative factors to help keep your eyes comfortable while working at the computer for long extended periods of time, for short computer-sessions the following factors are probably unnecessary. (after all our eyes adapt very well to changing stimuli)

Screen Brightness/background

  • A bright white screen background might not be appropriate for extended periods in front of the computer: just like a very bright sunny day – without glassess – or staring directly at a lightbulb/LED, it will strain your eyes – make your eyes tired quickly.

  • Similarly, a dark screen background might not be appropriate for extended periods in front of the computer, a black screen background will make your pupils dilate in order to capture more light and read smaller text, coupled with daylight or a well-lit room your eyes will strain – for the reasons mentioned above.

As you can probably guess:

  • The key is in matching the screen brightness/color with that of ambient light. Ideally you want the screen birghtness/color to match that of your surrounding environment, e.g:
    • Light-gray/light-yellow backgrounds for light themes, or alternatively,
    • Dark-gray backgrounds for dark themes

    This reduces the effort/strain on your eyes when staring at your monitor.

Text Contrast

While it may seem intuitive to have a high color contrast between the text and background – for legibility – and this is indeed the strategy used for caution/warning and street signs, this is not necessarily optimal for long reading sessions.

  • A more comfortable – medium – reading contrast is preferred, e.g:
    • A dark-gray on light-gray/yellow backgrounds for light themes – akin to reading a book on the shade, or a newspaper on the living room, or alternatively,
    • A light-gray on dark-gray background for dark themes

Text Size

Personally (highly subjective), I have found that a 12 size monospace font is a better – more comfortable – alternative to the smaller 10 size monospace (commonly used), while still allowing plenty of space after the standard 80 characters column mark.

However given my small (12.1” diagonal) current laptop display, on split windows I normally decrease the size to 10 monospace to fit all content. (this is not necessary if you have a larger display)

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