Related Experiment Videos
Impact resistance: an overview
Journal of the American Optometric Association
|August 1, 1982
Summary
Ophthalmic lens impact resistance is often below theoretical glass strength, influenced by surface flaws. Current FDA drop ball testing may not fully assess performance, prompting research into alternative evaluation methods.
Area of Science:
- Materials Science
- Ophthalmic Optics
- Mechanical Engineering
Background:
- Ophthalmic lenses have impact resistance well below theoretical glass strength.
- Surface flaws significantly alter lens impact resistance.
- Existing testing methods may not adequately evaluate lens performance.
Purpose of the Study:
- To review basic concepts of impact resistance in ophthalmic lenses.
- To discuss research on materials, treatments, and testing procedures.
- To explore factors affecting fracture mechanisms and impact resistance.
Main Methods:
- Literature review of impact resistance concepts.
- Analysis of research on materials, treatments, and fracture mechanisms.
- Discussion of the Food and Drug Administration (FDA) mandated drop ball test.
Main Results:
- Lens strength, treated or untreated, is significantly lower than theoretical glass strength.
- Surface breaks critically affect a lens's impact resistance.
- The FDA drop ball test is considered a control test with questionable performance evaluation validity.
Conclusions:
- Surface integrity is crucial for ophthalmic lens impact resistance.
- Alternative testing methods are proposed for more valid assessment of ophthalmic lens impact resistance.
- Further research is needed to refine impact resistance testing for ophthalmic lenses.