Tonometer system for measuring intraocular pressure by applanation and/or indentation

A system for measuring intraocular pressure by indentation, said system comprising:

• an indentation device for placement in contact with a cornea and for indenting the cornea, said indentation device comprising:
• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole, said movable central piece being arranged so that sliding thereof toward the cornea causes indentation of a portion of the cornea when the indentation device is located on the cornea;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea beyond a flattening of the cornea to thereby indent said portion of the cornea using a predetermined amount of force;
• distance detection means for detecting a distance travelled by said movable central piece;
• means for determining intraocular pressure based on the distance travelled by said movable central piece in response to said predetermined amount of force;
• a display for displaying said intraocular pressure and indicating whether the intraocular pressure is within certain ranges so as to determine if action should be taken in connection with the intraocular pressure;
• and
• said ranges being adjustable to compensate for different patient sensitivities to changes in intraocular pressure.

A method for non-invasively measuring outflow facility of the eye, said method comprising the steps of:

• placing an indentation device in contact with a cornea;
• moving at least one portion of said indentation device toward the cornea using a first predetermined amount of force to achieve indentation of the cornea;
• determining an intraocular pressure based on a first distance travelled toward the cornea by said at least one portion of said indentation device during application of said first predetermined amount of force;
• rapidly reciprocating said at least one portion toward and away from the cornea at a first predetermined frequency and using a second predetermined amount of force during movement toward the cornea to thereby force intraocular fluid out from the eye, said second predetermined amount of force being less than said first predetermined amount of force;
• moving said at least one portion toward the cornea using a third predetermined amount of force to achieve indentation of the cornea;
• determining a second intraocular pressure based on a second distance travelled toward the cornea by said at least one portion of said indentation device during application of said third predetermined amount of force;
• again rapidly reciprocating said at least one portion toward and away from the cornea, at a second predetermined frequency and using a fourth predetermined amount of force during movement toward the cornea, to thereby force more intraocular fluid out from the eye, said fourth predetermined amount of force being greater than said second predetermined amount of force;
• subsequently moving said at least one portion toward the cornea using a fifth predetermined amount of force to again achieve indentation of the cornea;
• determining a third intraocular pressure based on a third distance travelled toward the cornea by said at least one portion of said indentation device during application of said fifth predetermined amount of force;
• calculating differences between said first, second, and third distances, said differences being indicative of the amount of intraocular fluid which left the eye and therefore being indicative of the outflow facility.

A device for placement in contact with a cornea and for applanating or indenting the cornea, said device comprising:

• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening or indenting a portion of the cornea when the device is located on the cornea;
• said movable central piece having a substantially transparent peripheral portion.

A device for placement in contact with a cornea and for applanating or indenting the cornea, said device comprising:

• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening or indenting a portion of the cornea when the device is located on the cornea;
• and
• said movable central piece including a transparent central portion.

A device for placement in contact with a cornea and for applanating or indenting the cornea, said device comprising:

• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening or indenting a portion of the cornea when the device is located on the cornea;
• means for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea to flatten or indent said portion of the cornea, said means for actuating being configured such that an inside of a patient's eye remains visible during actuation.

A system for measuring intraocular pressure by applanation, said system comprising:

• a device for placement in contact with a cornea and for applanating the cornea, said device comprising:
• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening a portion of the cornea while the device is located on the cornea;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea to flatten said portion of the cornea;
• detection means for detecting when a predetermined amount of applanation of the cornea has been achieved;
• and
• means for determining intraocular pressure based on an amount of force said movable central piece must apply against the cornea in order to achieve said predetermined amount of applanation;
• said movable central piece including at least one transparent area, and wherein said detection means comprises an optical detection system including:
• a source of light for emitting a primary beam of light toward the cornea through said at least one transparent area, said primary beam of light being reflected back through the device by the cornea, when said device is located on the cornea, in a manner indicative of the amount of applanation of the cornea;
• and
• a light sensor arranged with respect to said reflected beam of light so as to produce an output signal indicative of the amount of applanation.

A system for measuring intraocular pressure by applanation, said system comprising:

• a device for placement in contact with a cornea and for applanating the cornea, said device comprising:
• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening a portion of the cornea while the device is located on the cornea;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea to flatten said portion of the cornea;
• detection means for detecting when a predetermined amount of applanation of the cornea has been achieved;
• means for determining intraocular pressure based on an amount of force said movable central piece must apply against the cornea in order to achieve said predetermined amount of applanation;
• and
• sighting means for indicating when said actuation apparatus and said detection means are properly aligned with said device.

A system for measuring intraocular pressure by applanation, said system comprising:

• a device for placement in contact with a cornea and for applanating the cornea, said device comprising:
• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening a portion of the cornea while the device is located on the cornea;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea to flatten said portion of the cornea;
• detection means for detecting when a predetermined amount of applanation of the cornea has been achieved;
• means for determining intraocular pressure based on an amount of force said movable central piece must apply against the cornea in order to achieve said predetermined amount of applanation;
• and
• distance measurement means for indicating whether said device is at a proper axial distance from said actuation apparatus and said detection means.

A system for measuring intraocular pressure by applanation, said system comprising:

• a device for placement in contact with a cornea and for applanating the cornea, said device comprising:
• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening a portion of the cornea while the device is located on the cornea;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea to flatten said portion of the cornea;
• detection means for detecting when a predetermined amount of applanation of the cornea has been achieved;
• means for determining intraocular pressure based on an amount of force said movable central piece must apply against the cornea in order to achieve said predetermined amount of applanation;
• and
• alignment means for indicating whether said device is properly aligned with said actuation apparatus and said detection means.

A system for measuring intraocular pressure by applanation, said system comprising:

• a device for placement in contact with a cornea and for applanating the cornea, said device comprising:
• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening a portion of the cornea while the device is located on the cornea;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea to flatten said portion of the cornea;
• detection means for detecting when a predetermined amount of applanation of the cornea has been achieved;
• means for determining intraocular pressure based on an amount of force said movable central piece must apply against the cornea in order to achieve said predetermined amount of applanation;
• and
• said actuation apparatus being configured such that an inside of a patient's eye remains visible during actuation.

A system for measuring intraocular pressure by indentation, said system comprising:

• an indentation device for placement in contact with a cornea and for indenting the cornea, said indentation device comprising:
• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole, said movable central piece being arranged so that sliding thereof toward the cornea causes indentation of a portion of the cornea when the indentation device is located on the cornea;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea beyond a flattening of the cornea to thereby indent said portion of the cornea using a predetermined amount of force;
• distance detection means for detecting a distance traveled by said movable central piece;
• and
• means for determining intraocular pressure based on the distance traveled by said movable central piece in response to said predetermined amount of force;
• said movable central piece having a substantially reflective portion and wherein said distance detection means comprises an optical distance detection system including:
• a source of light for emitting a primary beam of light toward said substantially reflective portion, said primary beam of light being reflected by said substantially reflective portion in a manner indicative of the distance traveled by the movable central piece toward the cornea, to thereby produce a reflected beam of light;
• and
• a light sensor arranged with respect to said reflected beam of light so as to produce an output signal indicative of the distance traveled.

A system for measuring intraocular pressure by applanation, said system comprising:

• a device for placement in contact with a cornea and for applanating the cornea, said device comprising:
• a substantially rigid annular member having an inner concave surface shaped to match an outer surface of the cornea and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening a portion of the cornea while the device is located on the cornea;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said cornea to flatten said portion of the cornea;
• detection means for detecting when a predetermined amount of applanation of the cornea has been achieved;
• and
• means for determining intraocular pressure based on an amount of force said movable central piece must apply against the cornea in order to achieve said predetermined amount of applanation;
• said actuation apparatus being configured such that an inside of a patient's eye remains visible during actuation.

A device for placement in contact with a body part and for applanating or indenting the body part, said device comprising:

• a substantially rigid member having an inner surface shaped to match an outer surface of the body part and having a hole defined therein;
• a movable central piece slidably disposed within said hole and having a substantially flat inner side for flattening or indenting a portion of the body part when the device is located on the body part;
• and
• a flexible membrane secured to said inner surface of the substantially rigid member, said flexible membrane being coextensive with at least said hole in the rigid member and having at least one transparent area.

A system for measuring internal pressure by indentation, said system comprising:

• an indentation device for placement in contact with a body part and for indenting the body part, said indentation device comprising:
• a substantially rigid member having an inner surface shaped to match an outer surface of the body part and having a hole defined therein;
• and
• a movable central piece slidably disposed within said hole, said movable central piece being arranged so that sliding thereof toward the body part causes indentation of a portion of the body part when the indentation device is located on the body part;
• an actuation apparatus for actuating said movable central piece to cause sliding of said movable central piece so that said movable central piece projects inwardly against said body part beyond a flattening of the body part to thereby indent said portion of the body part using a predetermined amount of force;
• distance detection means for detecting a distance traveled by said movable central piece;
• and
• means for determining internal pressure based on the distance traveled by said movable central piece in response to said predetermined amount of force;
• said movable central piece having a substantially reflective portion and wherein said distance detection means comprises an optical distance detection system including:
• a source of light for emitting a primary beam of light toward said substantially reflective portion, said primary beam of light being reflected by said substantially reflective portion in a manner indicative of the distance traveled by the movable central piece toward the body part, to thereby produce a reflected beam of light;
• and
• a light sensor arranged with respect to said reflected beam of light so as to produce an output signal indicative of the distance traveled.