Photo reactive glasses might not be so good in the dark, according to part of the MAIB report into the loss of the yacht Ouzo.
The lookout?s photochromic glasses were sent to University College London?s Institute of Ophthalmology to assess whether they might have had an adverse effect upon his night vision.
The glasses were examined and a report was prepared (Annex 1), which concluded that the optical transmission of the lenses was no more than 80% efficient and, taking into account all of the other known factors, was probably less at the time of the accident. This compares to 94.7% and 99.4% optical transmittance of ordinary uncoated and coated lenses, respectively. This was a startling result as the consequences of such a reduction in night vision had not been fully appreciated by opticians and ophthalmologists before the investigation of this accident.
That is quite a surprise to me, though i do not wear photo reactive glasses all that much, they tend to take quite a while before i feel comfortable outside, or go amazingly dark on overcast days…. I guess its another example of using the correct tool for the job, i.e. sunglasses for bright sunshine, and normal glasses for the rest of the time.
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