i am -4 and lost my glasses; however, i still keep my -2 glasses.
on a sunny day, outdoor, the -2 glasses works just fine. not 99% eagle eye precision, but like 90% precision, overkill to see car plates and directions.
does the intensity of light from sun cut -2 from -4 requirement?
Yes, in bright light your pupils are narrow enough to create a pinhole focus effect. (It works the same way with a camera: stop down your camera lens enough and you get infinite depth of field with every visible object in focus.)
In a dark room, your pupils will dilate and impact clarity of vision. If the room is well lit and screen brightness is matched to ambient light, there will be no effect on pupil dilation.
Oh, this is more "believe your way to a lower prescription" myopia skeptic stuff, isn't it. Yeah, sure, and in a pinch you can just glance up at the sun for a second to "improve" your vision.
on a sunny day, outdoor, the -2 glasses works just fine. not 99% eagle eye precision, but like 90% precision, overkill to see car plates and directions.
does the intensity of light from sun cut -2 from -4 requirement?