Rimless Eyewear
To help you to purchase and dispense the best glazed product for your patient we are pleased to provide some important information on rimless product. This guidance is offered without prejudice since we are keen to ensure that our valued customers understand that complex glazing issues can arise in respect of certain materials:
Recommended for Rimless Glazing
- 1.59 Index (Polycarbonate)
- 1.60 Index
- 1.67 Index
- 1.74 Index and Trivex (Trilogy or PNX)
Not recommended for Rimless Glazing:
- 1.50 Index
- 1.54 Index
- 1.56 and Sunsensors - these are brittle and unlikely to stand up to the stresses of everyday wear
We will only glaze these materials explicitly at your own risk as they are more likely to crack than the recommended materials.
Please bear in mind that all lenses, including Hi Index, must have a minimum substance of 2mm at the drill holes, both for strength and because the pins or barrels are normally 2mm in length and will not tighten if the lens is thinner.
- Polycarbonate is suitable for many types of Rimless mounts but there are some where this material is unsuitable, particularly where there is outward pressure on the holes or slots, which can cause cracks or crazing.
- Polycarbonate will craze if cleaned with Acetone and some other solvents. We respectfully suggest that great care is taken with the selection of cleaning solutions you use in your practice and those you recommend to patients, who should use only solvent and acetone free solutions to clean their spectacles.
We bring this issue to your attention as solvents are now added to many household cleaners, including washing up liquid. Glazing houses are reporting more and more cases of lenses crazing adjacent to the drill holes several months after glazing, which is probably caused by solvent attack.
We recommend Essiclean as a suitable lens cleaner - it can be used on all materials and coatings, including the new easy clean coatings like Crizal Alize and Nikon HCC Ikon.
We hope that the above guidance will be helpful in clarifying some of the essentials of good quality rimless glazing.
If you are unclear or would like further information, please email to info@eyeindex.co.uk, or call us on 01480 499600 and a member of our technical team will be happy to respond to your enquiry.
