Results 1 to 3 of 3

Thread: blue blocking

  1. #1
    OptiBoard Novice
    Join Date
    Nov 2019
    Location
    saudi arabia
    Occupation
    Optical Wholesale Lab (other positions)
    Posts
    1

    blue blocking

    An old yellowed CR39 lens has blue blocking capability is this right? Can a yellowed lens be used as a blue blocker?

  2. #2
    Rising Star
    Join Date
    Nov 2017
    Location
    Italy
    Occupation
    Other Eyecare-Related Field
    Posts
    81
    Quote Originally Posted by Ray2019 View Post
    An old yellowed CR39 lens has blue blocking capability is this right? Can a yellowed lens be used as a blue blocker?
    IMHO

    the yellow blocks the blue but it is hard to say how much it cut without a Spectrometer.

    Different batch of old lenses may have different result for sure.

    I prefer a new lenses coated properly.

  3. #3
    Master OptiBoarder rbaker's Avatar
    Join Date
    May 2000
    Location
    Gold Hill, OR
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    4,347
    As CR-39 lenses age they deteriorate. A few years ago I came across some + spheres that had been peacefully sleeping in a box in my garage since I retired in 2002. Took a +2.00 out of its envelope and as expected it was schict brindle yellow/brown. I was also able to break it in half with hardly any effort. The lens was sort of "crumbly" From an impact resistand standpoint, totally unusable.

    If its "yellow" toss it out.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Essilor blue blocking
    By bta89 in forum General Optics and Eyecare Discussion Forum
    Replies: 6
    Last Post: 08-10-2018, 03:52 PM
  2. How old are the Blue Blocking lenses ? .............................
    By Chris Ryser in forum General Optics and Eyecare Discussion Forum
    Replies: 11
    Last Post: 04-05-2018, 09:33 AM
  3. Blue light blocking lenses
    By LENNY in forum General Optics and Eyecare Discussion Forum
    Replies: 7
    Last Post: 11-16-2017, 11:55 AM
  4. NASA on blue blocking lenses ..................................
    By Chris Ryser in forum General Optics and Eyecare Discussion Forum
    Replies: 6
    Last Post: 04-18-2016, 07:34 PM
  5. Rodenstock and blue blocking lenses...................
    By Chris Ryser in forum General Optics and Eyecare Discussion Forum
    Replies: 1
    Last Post: 09-20-2008, 09:21 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
OptiBoard is proudly sponsored by:
Younger Optics and Vision Equipment