by Steve » Mon Nov 25, 2019 5:43 pm
There are a couple of issues with red light illumination at night. The first is Red Light Presbyopia. This is mostly seen in early presbyopes (48-54 years old). Your eye needs more accommodation to focus red light. Couple this with the larger pupil in dim illumination, and you will have more blurred images in red light. This isn't an issue for many of us who are old enough to be fully-developed presbyopes, with virtually no accommodation, and we use spectacles to correct for near vision.
There is also the issue of iatrogenic dyschromatopsia (alteration of color perception under single color illumination). This may or may not be an issue, since most of us do not use paper charts anymore.
These two factors led to aircraft manufacturers switching to dim white from dim red panel illumination in the 1970s to 1980s.
The above information is a result of my experience as a Navy Flight Surgeon and ophthalmologist...
Steve
PS: What Colin said about O2 is very important. In the P3C community the cockpit crew went on O2 one hour before landing at night.
There are a couple of issues with red light illumination at night. The first is Red Light Presbyopia. This is mostly seen in early presbyopes (48-54 years old). Your eye needs more accommodation to focus red light. Couple this with the larger pupil in dim illumination, and you will have more blurred images in red light. This isn't an issue for many of us who are old enough to be fully-developed presbyopes, with virtually no accommodation, and we use spectacles to correct for near vision.
There is also the issue of iatrogenic dyschromatopsia (alteration of color perception under single color illumination). This may or may not be an issue, since most of us do not use paper charts anymore.
These two factors led to aircraft manufacturers switching to dim white from dim red panel illumination in the 1970s to 1980s.
The above information is a result of my experience as a Navy Flight Surgeon and ophthalmologist...
Steve
PS: What Colin said about O2 is very important. In the P3C community the cockpit crew went on O2 one hour before landing at night.