Hi, [s2Get user_field=”first_name” /].
While we wait on your normalized prescription, let’s cover a few other close-up related topics in some of these sessions.
Today, briefly, let’s look at brightness.
The first rule of close-up work, have good ambient brightness. Guideline there is the equivalent of shaded natural light you would get outdoors, or about 1000 lux. If you are unfamiliar with lux, check out the wikipedia page on lux here.
You can download a light meter app for Android or iPhone and check out the lux for your given ambient environment.
I highly recommend it!
Be sure to check out the instructions for the app. A lot of time they use the front facing camera, so you have to sometimes turn the phone around to get the lux of where you are actually looking at (if for example you are facing a window, which is my personal preference for working indoors).
1000 lux is ideal.
You might want to compare your centimeter in a 1000 lux environment to a 400-500 lux environment (your typical fluorescent lit office). Even if you do it casually without a measuring tape, you’ll notice a possibly significant difference in available distance.
A word of disclosure: This is one of those topics that isn’t rooted in clinical science. While most of what we talk about is either scientific fact (centimeter, diopters), or at least well researched (lens-induced myopia, pseudopmyopia), this ambient lighting subject is specifically my own findings.
If you always work in 400 lux artificial lighting, your improvement in eyesight year over year is statistically 25-35% slower than if you have a 1000 lux naturally lit environment. I gathered this data over an eight year period, with 90 participants in various age and myopia ranges.
In other words, less ambient lighting won’t stop you from improving, but it will slow you down.
Not all lux are created equal. The light meter is just a very basic guide to help you compare how much ambient light might be reaching your eyes.
Natural light is full spectrum UV and is more effective in providing a stable centimeter distance than various narrow spectrum artificial light sources. Supplementing that type of artificial light with some full spectrum bulbs is something I’d suggest.
Don’t try to rig your lux.
No pointing light sources towards your face, no squinting, no tricks. It doesn’t help, there is no quiz on your lux exposure. We are talking just about the ambient environmental light. Your single best guide on this front are your own eyes. Check your centimeter distance for various ambient lighting conditions. Be sure to include the ideal one as a reference, a shaded outdoor 1000 lux environment. (next to an office window will do nicely)
There is also the subject of screen brightness.
Important Note: If you are going to use indoor lights for additional brightness, be sure to buy good quality “daylight bulbs”. Avoid “full spectrum” that are meant to grow plants or for animals. You want bulbs with wide natural spectrum light, but without the UVA and UVB parts of the spectrum (which are part of the “grower” type of bulbs – avoid those!)
This is a longer subject, though for now just the short version: No lux measuring, just subjectively, the screen should “feel” like it matches ambient brightness. It shouldn’t be subjectively dim, nor bright. Apple seems to do this better than most, in their Macbook lineup of late. (if you happen to have one of those around, for reference)
And lastly, don’t get paralyzed by sessions like this one. These are just suggested tweaks, and tools and awareness building activities. It doesn’t mean you need to quit your job because the lighting sucks. Just realize that these aspects all play into your eyesight. It’s why you got yourself the eye guru, rather than relying on a book or some Internet forum. We cover all the things that actually matter to eyesight health. 😉