I am not an authority on colour deficiency, but what I have read about online glasses is not very supportive. Three patients of mine have all said the lenses help with colour differentiation but decrease light to the extent that they found wearing them indoors problematic.

I would urge prospective customers of such lenses to seek consultations with practitioners who are experienced in the techniques of prescribing and to have seen and looked through the lenses recommended before agreeing to go ahead.

I would not be confident using an online service unless I was satisfied there was good scientific evidence that it worked and was safe. For that reason, I would not be able to recommend it to a patient at this time.