Toric contact lens with axis offset compensation and method and apparatus for manufacturing same
US6135594A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1998 |
| Grant date | Oct 24, 2000 |
| Priority date | — |
| Expiry date | Dec 21, 2018 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29D11/00951
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A contact lens and a method and apparatus for manufacturing a contact lens having areas of different thickness, the contact lens being compensated for differential shrinkage during the manufacturing process. The angular offset of the cylinder axis due to differential shrinkage is compensated for by introducing an equal and opposite offset during the manufacturing process. The axis offset caused by a particular manufacturing process is experimentally determined, i.e., for each intended cylinder axis, the corresponding offset (in terms of degrees of rotation) is determined. The lens compensation is implemented by adjusting the manufacturing process so that upon curing the lens corresponds to the desired, prescribed lens, without any axis offset.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.