Ophthalmological instrument

• US 5,032,020 A
• Filed: 12/22/1988
• Issued: 07/16/1991
• Est. Priority Date: 02/09/1988
• Status: Expired due to Term

• Current Assignee: SMT Swiss Microtechnology AG (Ziemer Group AG)
• Original Assignee: Yves Robert
• Inventors: Robert, Yves
• Primary Examiner(s): Dzierzynski, Paul M.
• Application Number:
  US07/288,097
• Time in Patent Office: 936 Days
• Field of Search: 351/219, 351/221, 128/646, 128/645, 128/648, 128/652
• US Class Current: 351/219
• CPC Class Codes: A61B 3/16 for measuring intraocular pressure, e.g. tonometers

Abstract

The ophthalmological instrument serves for examining the background (7) of the eye with simultaneous determination of intraocular pressure. A transparent contact member (1) has a concavely curved surface (13) adapted to the curvature of the cornea (11) of the eye (6). In the center of this curved surface (13), a transparent pressure transmitting element (25) is arranged which acts on a pressure sensor (23) by way of a cavity (19) filled with a liquid (26). The contact member (1) is designed as an imaging optical component forming together with the observation optic (9) an observation device for examination of the eye background (7). Additional pressure sensors (27) are located at the rim of the concave curvature (13) of the contact member (1), these additional pressure sensors, on the one hand, monitoring an exact positioning of the contact member (1) and, on the other hand, eliminating falsification of the measured value, caused by the contact pressure of the contact member (1) against the eye (6), by means of an electronic measuring data evaluation.

Claims

1. An ophthalmological instrument comprising, a corneal contact member (1) designed as a imaging optical component with a corneal contact surface (13) for contacting the cornea (II) of the eye (6),

a pressure measuring device (19, 21, 23, 25, 26, 27) for determining intraocular pressure,

said pressure measuring device (19, 21, 23, 25, 26, 27) including pressure responsive means (25, 32) arranged at said corneal contact surface (13) of said corneal contact member (1) in order to impress or applanate a part of the cornea (11) of the eye (6),

said corneal contact surface (13) of said corneal contact member (1) having a concave shape approximately adapted to the shape of the eye (6), the concave shape of the corneal contact surface (13) has a rim, and said pressure measuring device (19, 21, 23, 25, 26, 27) for determining intraocular pressure includes a first pressure sensor (23) for measuring the pressure exerted by the cornea (11) of the eye on said pressure responsive means (25, 32), at least a second pressure sensor (27) arranged adjacent said rim of said concave shape corneal contact surface (13) for measuring the contact pressure of said contact member (1) against the eye (6), and an electronic evaluating circuit (28) calculating the difference of the electric signals from the first (23) and the second (27) sensor, or the difference between the signal of the first sensor (23) and the average value of the signals from the second sensors (27), wherein a display means (33, 39) is provided which indicates this difference directly and/or the eye pressure determined from this difference.

2. An ophthalmological instrument comprising, a corneal contact member (1) designed as an imaging optical component with a corneal contact surface (13) for contacting the cornea (11) of the eye (6),

a pressure measuring device (19, 21, 23, 25, 26, 27) for determining intraocular pressure including a pressure sensor (23),

said pressure measuring device (19, 21, 23, 25, 26, 27) including a pressure transmitting member (25, 32) arranged at said corneal contact surface (13) of said corneal contact member (1) in order to impress or applanate a part of the cornea (11) of the eye (6), and including a cavity (19) in said corneal contact member (1),

said pressure transmitting member (25, 32) connected to seal off said cavity (19) in said corneal contact member (1),

said cavity being filled entirely with a transparent liquid (26), the index of refraction of the liquid (26) being at least approximately equal to that of the corneal contact member (1),

said pressure sensor (23) connected with said cavity (19) to be acted upon by said liquid (26), said corneal contact member (1) has a side surface (17) beyond said corneal contact surface (13), said cavity (19) extends to said side surface (17), and a plunger means (30) is provided in said cavity (19) at said side surface (17).

3. An ophthalmological instrument, comprising

a corneal contact member (1) with a corneal contact surface (13) to be pressed against the cornea (II) of the eye (6),

said corneal contact member (1) being designed as an imaging optical component, through which the background (7) of the eye (6) can be illuminated and observed,

said corneal contact surface (13) of said corneal contact member (1) to be pressed against the eye cornea (11) having a concave shape approximately adapted to the shape of the eye (6), and the concave shape corneal contact surface having an outer rim,

a pressure measuring device (19, 21, 23, 25, 26, 27) for determining intraocular pressure,

said pressure measuring device (19, 21, 23, 25, 26, 27) including a pressure responsive means (25;

32) arranged at said corneal contact surface (13) of said corneal contact member (1) in order to impress or applanate a part of the cornea (11) of the eye.

said pressure measuring device (19, 21, 23, 25, 26,

     27) for determining intraocular pressure including a first pressure sensor (23) for measuring the pressure exerted by the impressed or applanated part of the cornea (11) of the eye on said pressure responsive means (25,

     32), at least a second pressure sensor (27) arranged adjacent said rim of said concave shape corneal contact surface (13) for measuring the contact pressure of said contact member (1) against the eye (6), and an evaluation or calculation means (28) for determining the intraocular pressure as the difference of the pressure of the impressed or applanated part of the cornea (11) of the eye (6) on said pressure responsive means (25,

     32) and the contact pressure of said contact member (1) against the eye (6) from said at least one second pressure sensor (27).

4. An ophthalmological instrument according to claim 3, wherein said at least one second pressure sensor (27) includes wherein said at least one second pressure sensor (27) includes plural second pressure sensors (27) arranged adjacent said rim of said concave shape corneal contact surface (13), said evaluation or calculation means (28) for determining the intraocular pressure has a electronic evaluating circuit (28) for calculating the difference of the electric signals from said first sensor (23) and said second sensors (27), or the difference between the signal of the first sensor (23) and the average value of the signals from the said second sensors (27), and a display means (33, 39) connected to said electronic evaluating circuit (28) which indicates this difference directly and/or the eye pressure determined from this difference.

5. An ophthalmological instrument according to claim 4, in which at least three of said second sensors (27) are arranged with at least approximately identical angular spacings from one another adjacent the rim in the concave corneal contact surface (13), and that the display means (33, 39) with said electronic evaluating circuit (28) indicates, with adequately mutually coinciding signals of these three pressure sensors (27), the position of the corneal contact member (1) centered with respect to the eye (6) and, with differing signals of these three sensors (27), the direction or coordinate directions in which corneal contact member (1) is to be shifted into its position centered with respect to the eye (6).

6. An ophthalmological instrument, comprising

a corneal contact member (1) with a corneal contact surface (13) to be pressed against the cornea (11) of the eye (6),

said corneal contact member (1) being a rigid transparent member designed as an imaging optical component, through which the background (7) of the eye (6) can be illuminated and observed,

said corneal contact surface (13) of said corneal contact member (1) to be pressed against the eye cornea (11) having a concave shape approximately adapted to the shape of the eye (6), and the concave shape corneal contact surface having an outer rim,

a pressure measuring device (19, 21, 23, 25, 26, 27) for determining intraocular pressure,

a cavity (19) in said corneal contact member (1),

said cavity (19) extending to an opening (16) in said corneal contact surface (13), said opening (16) being sealed off by a transparent membrane (25), said transparent membrane (25) on the opening (16) having a planar surface, said cavity (19) being filled entirely with a transparent liquid (26), the index of refraction of the liquid (26) being at least approximately equal to that of the corneal contact member (1),

said pressure measuring device (19, 21, 23, 25, 26, 27) for determining intraocular pressure including a pressure sensor (23) arranged in said cavity (19) for measuring the pressure of said liquid (26),

said cavity (19) being sealed off in a leakproof fashion, so that the membrane (25) on the opening (16) retains its planar surface during the pressure contact of said corneal contact surface (13) of said corneal contact member (1) to the eye cornea (11), whereby the part of the eye cornea (11) contacting the membrane (25) being applanated and the intraocular pressure exerting a force on the membrane (25) and by way of said liquid (26) on said pressure sensor (23) arranged in said cavity (19).