Air-puff tonometer
US4996990A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 12, 1988 |
| Grant date | Mar 5, 1991 |
| Priority date | — |
| Expiry date | Aug 12, 2008 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/165
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An air-puff tonometer, in which a puff of compressed air is blown out through a nozzle (N) toward the cornea of a subject eye (H), said compressed air being produced by energizing with an electric current a piston drive, which when thus driven compresses the air within a cylinder (5) in which the piston is mounted. The tonometer is provided with: pressure detector (11) for detecting the pressure within the cylinder (5); and current control (12, 14) for comparing a pressure signal (Vp) outputted from said pressure detector (11) with a predetermined reference signal (Vt) and for controlling the current supplied to said piston drive in such a manner that the difference between said pressure signal and said reference signal will be reduced. The air-puff tonometer so constructed will allow air within the cylinder thereof to be compressed in accordance with a predetermined pressure-time characteristic curve in spite of any change occurring in the clearance between the piston and the cylinder walls. Other tonometers are also disclosed which are arranged to detect the actual air-puff pressure at the moment the cornea flattens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.