Photochromic lenses

[compo]

I have bi-focal glasses with transitions lenses. When the sun is behind me at an angle that it can shine onto the back of the lense the light is focuses and beamed straight into my eye. It is so powerful it is like being punched and all I can see are pretty coloured zig-zag patterns. This morning, whilst cycling, I nearly passed out and it took me a few minutes to recall it happening before and what the cause was. Once I removed my glasses all was well, apart from my defective eyesight! I think in future it is clear lenses or cheap sunglasses that wont focus the light so much.

Has anyone else experienced this or am I just peculiar.

 

[Scoosh]

I have varifocal transition lenses and have not experienced this - I find the shadow of my helmet keeps the sun off the lenses.

I wouldn't state that you are peculiar (I don't know you ) but it does sound a bit disconcerting. Maybe a cap/hat/something with a brim would eliminate this issue.

 

[Globalti]

Be careful; if a lens or mirror reflects a concentrated beam of sunlight into your eye it can burn your retina.

(We knew someone whose bedroom caught fire, the insurers sent a forensic investigator who worked out that sunlight concentrated by a witchy glass sphere on her window sill had set fire to the curtains!)

 

[doug]

Wouldn't you get the same effect with any bifocal lens whether clear or dark ? I'd think it would be more due to the shape of the lens than its colouring.

I wear single vision photochromatic lenses without problem, but they wrap around, have thick arms and I wear a helmet so the chances of light being reflected off the inside is remote.

 

[compo]

Wouldn't you get the same effect with any bifocal lens whether clear or dark ? I'd think it would be more due to the shape of the lens than its colouring.

I wear single vision photochromatic lenses without problem, but they wrap around, have thick arms and I wear a helmet so the chances of light being reflected off the inside is remote.

I also wear a helmet with a peak. I suspect the fact my glasses are bifocal has nothing to do with the reflection. I don't know if the photochromic effect is impregnated into the glass or is it a coating on the lense. If a coating then light falling onto the clear side of the lense could cause a mirror effect. It hasn't happened a lot to me which is why it didn't register immediately what was happening and as I said in my OP it is when the sun is behind me at an angle it happens, so a helmet peak offers no protection.

 

[ianrauk]

These may help