NIKON 1.6 progressive lenss

**Ivars Kutkovskis** · 07-31-2013, 09:03 AM

Hi pro's. I have a questions. Ive been workin 4 about 10 years and never had i kind of problem since... Costumer bring back glasees with AR coating cracks for NIKON Progresivse lenses TRasition 1.6 -6.00 add 1.5 So i send them to test to the Center of Optometry. They mention coupe of reasons - but the main was LENSS TENTION in frame - they tested trough the tensionmeter. Probem is that i dont thing that such a hard ar pretty thick lenss can crack. Anyway - they told me that other optitian sed that there is no extra tension. any ideas? Tention? No i dont think so.

**Slim** · 08-01-2013, 05:41 PM

So you see cracking in the AR coating yes? Not the lens plastic?

Extreme heat can crack the AR or if the lens has flexed to far.

**golfnut** · 08-02-2013, 11:37 PM

Tension from from the fit in the frame can cause fracturing around the thin point on the lense. I have seen this. It's very hard to find unless you really look at the right angle or use a high intensity light source. I have only noticed in really thin stock lenses. Usually in small B the Rectangle type frames.