Choose an Optical Shop
Chandra Richardson at Lahey Hospital & Medical Center Optical Shop makes the glasses for our daughter. (She sends them out to a lab for the tinting, she doesn’t have a lab in house.) She will work with customers by mail but I recommend finding an optical shop near your home. Getting the tinting right can take a bit of trial and error, so its important to find one that has the patience to keep tinting and re-tinting lenses until they are right. If you have an optical shop to recommend, let me know and I’ll share it here. It would be great to get a list of optical shops experienced with custom tinting that are all over the country/world.
Choose a Lens Material
One of our early mistakes was using the default lens material for kids—polycarbonate—normally chosen because it is lightweight and impact resistant (hence safe). Unfortunately you cannot tint it dark enough for use outside, and any tint you do apply fades over time. So even if you tint a pair dark enough for indoor use, they don’t stay that way long. Just stay away from polycarbonate.
I know of two alternatives that do work, CR-39 and Trivex. Our daughter used to wear CR-39 lenses but we’ve now switched to Trivex. Both CR-39 and Trivex can be tinted dark enough and do not fade. The advantage of CR-39 is that it is relatively inexpensive. Trivex is more expensive, but it has better impact resistance (so may be safer for sports etc.) and is lighter weight.
Choose a Dye
We use BPI FL-41 (Also called BPI# 37616) for all of our daughter’s glasses. We tint them to an average transmission of about 5% for an outdoor pair, and to an average transmission of about 45% for an indoor (bright lighting) pair.
According to my daughter, the indoor pair end up pretty similar to NoIR Filter #95. The outside pair end up as effective at blocking light as NoIR Filter #93, but my daughter likes the FL-41 dye better than NoIR Filter #93. She says the NoIR Filter #93 “changes the colors” but the custom tint doesn’t as much. (The reason for the difference is that NoIR Filter #93 only lets red light through, but FL-41 lets a tiny bit of blue and green through. I think that BPI #37880 would be able to better match NoIR #93 if that were your preference.)
To tint a spectacle lens red use BPI Deep Red #37880… For a lighter red use BPI Red #31900. For a red/brown I use AO Sahara #21100. AO Sahara can be used for a light indoor tint or darkened enough for outdoors for someone who is only mildly photophobic.
Unfortunately, experimenting with tints is a lot harder and more expensive than experimenting with NoIR lenses. One option is to experiment to find the NoIR tint you like best, and then try to find a dye that matches by comparing spectral curves. That’s a bit complicated, but if you are interested, you can read more here.
We didn’t get our daughter’s Rx lenses tinted dark enough for outside until we tried the NoIR #93 lenses and learned how good really dark glasses can be. Before trying the NoIR #93 lenses, we thought we had her outside glasses tinted dark enough. After all they were soooo much better than anything she had worn before. But when we tried the NoIR #93 we realized we needed to tint them even darker. Yes, you can do as well as NoIR #93 with a custom tint, but I think its helpful to try the NoIR #93 or #99 just to see how good they can be and to have something to try to match in performance with any custom tinting.