Low contrast modes that rely on colour are not a boon, despite the design trends. Complementary colour contrasts may be perceived as strenuous but overall eye fatigue is reduced and readability improved if the contrast is high!
Themes like "solarized" are quite terrible in most situations.
It was believed that because screen reflections are imaged behind ...
There are more problems which can occur from "staring" on screen.
Dry or watering eyes
Changes in color perception
Difficulty focussing (1, 2, 3)
Ways to minimise damage to your eyes caused by computer screens There
are several ways you can minimise the potential damage to your eyes
Retina Display is unhealthy, but it's unrelated to the resolution. It's the fact, that it's offered only as glossy display, no matte option.
Queensland University of Technology page on "High gloss computer screens"
This web page contains health and safety considerations for Macintosh
– Apple ‘glass’ or high gloss monitor screens.
Reflections and ...
It may delay development in childhood. It can cause depression in adulthood..
Findings so far are developpement lateness. I couldn't find a study showing these damages would be permanent, though. I'm going to assume here you mean media exposure and not just empty screen staring.
This paper gives convincing evidence that the brain structure could be affected ...
Computer Eye Strain: 10 Steps for Relief says, "Choose a display with a dot pitch of .28 mm or smaller."
According to MacBook Air - Technical Specifications (with the help of Display PPI (Pixels Per Inch) Calculator), the 13-Inch MacBook Air's dot pitch is 0.1989 mm (127.68 PPI), smaller than 0.28 mm.