AR coating and lens powers

[Monkeysee]

Can the ar coating process cause lens power discrepancies? I get lenses back from coating every now and then, in which the powers are off slightly, even though the blanks were checked for accuracy before being shipped for coating.

Just wonderin....anyone else had this happen?

Thx.

[Jacqui]

Shouldn't.

[Chris Ryser]

Can the ar coating process cause lens power discrepancies? I get lenses back from coating every now and then, in which the powers are off slightly, even though the blanks were checked for accuracy before being shipped for coating.

Just wonderin....anyone else had this happen?

Thx.

Could be that they messed up the lens and made a new one. Make a mark on the edge to recognize your own lens coming back.

[thep]

Actually, yes. Depending on the lens material and the thickness of the lens, the heat process in the AR lab can potentially have an effect on powers. Minus lenses in any type of hi index are most susceptible.

[MarcE]

You bet, I've seen it myself. I even got some back that were warped beyond use from heat.