Abstract: A device and method for providing a stimulus to the measurement of the field of vision of the human eye. The stimulus is presented at predetermined test sites in a region of the background of a perimeter to a person to be tested. The stimulus has at least two visual characteristics that can be varied for the determination of a threshold. The stimulus is preferably formed by sine waves.

Abstract: A perimeter for visual examination has a head restraint and a control panel. Located on a unit base is an optical system, in which there is an optical examination system with an eyepiece. The optical system is movably mounted on the unit base and can be adjusted by means of at least one drive. The optical system can be tracked for precise positioning with respect to the eye being examined. The perimeter makes it possible to position the optical system in essentially any desired position.

Abstract: A device and method for providing a stimulus to the measurement of the field of vision of the human eye. The stimulus is presented at predetermined test sites in a region of the background of a perimeter to a person to be tested. The stimulus has at least two visual characteristics that can be varied for the determination of a threshold. The stimulus is preferably formed by sine waves.

Abstract: A method for testing the visual functions of a human eye by means of a perimeter which is placed at a location allowing observation, by the eye to be tested, along an observation axis. The method makes use of means associated with a light source for the chronologically staggered generation of stimuli at selected locations in the vicinity of a fixation mark located on the observation axis, and makes use of a camera linked to a computer for the observation of the position of the eye and direction of gaze. The method accommodates the diversion of the subject's gaze and incorrect placement of the subject's eye.

Abstract: A perimeter for visual examination has a head restraint and a control panel. Located on a unit base is an optical system, in which there is an optical examination system with an eyepiece. The optical system is movably mounted on the unit base and can be adjusted by means of at least one drive. The optical system can be tracked for precise positioning with respect to the eye being examined. The perimeter makes it possible to position the optical system in essentially any desired position.

Abstract: For purposes of examination, the human eye at a defined viewing point is oriented along a viewing axis. Using means associated with a first light source, stimuli are generated at selectable locations on the background of the viewing axis. Using a second light source, a homogeneous background light is generated around the viewing axis. The second light source has at least one LED. This LED can be actuated as required so that it generates a constant background light or a flickering background light. If at least two LEDs are used, the one LED can generate a colored background light by means of a fixed colored filter. No moving parts are necessary for the generation of a flickering background light, nor any means for the active cooling of the second light source.

Abstract: A computerized perimeter is utilized to examine the field of vision of a subject's eye while the eye is located at or at least close to a predetermined position in which the optical axis of the eye is maintained in or at least close to a predetermined orientation. The eye is presented with a sequence of stimuli which issue from a radiation source and are transmitted, as a rule only once, to each of a plurality of computer-selected locations in the area of the optical of the eye at the predetermined position. The value (the intensity and/or the size) of each stimulus is increased until the eye discerns the presented stimulus and the subject reacts as a result of discernment of the presented stimulus. Subjective and/or objective signals are generated by the subject in response to detection of stimuli, i.e., each such signal can be said to denote that value of a stimulus which is sufficiently high to ensure discernment of the stimulus by the eye.

Abstract: An automatic perimeter wherein the eye to be examined is maintained in a predetermined position to look at an eyepiece which focuses enlarged images of a series of stimuli on the retina. Stimuli are presented by a light emitting diode in combination with a diaphragm and are projected into selected locations around the optical axis of the eye. The perimeter operates without a cupola and is further provided with a system for illuminating the area in front of the eye as well as with a camera which images the eye onto the screen of a monitor so that the person in charge can ascertain whether or not the eye is focused upon a reference point on the optical axis of the eyepiece.

Abstract: The extent of clouding of the lens of a human eye is measured and quantified by directing a beam of electromagnetic radiation through the iris and against the clouded portion of the lens so that the clouded portion disperses and reflects the incident radiation. A selected part of reflected radiation which makes an angle of 10.degree.-40.degree. with the beam of incident radiation is monitored for intensity by a photoelectronic transducer whose signals are transmitted to an ammeter or to a microprocessor which latter transmits modified signals to a display unit and/or to a printer. The clouded portion of the lens can be observed through an optical system with an ocular whose axis coincides with a portion of the path of incident radiation.

Abstract: A tonometer which is used to measure the tension of eyeballs has a first testing device with a first outwardly bulging deformable wall which can be pressed against the eyeball (either directly or by way of the eyelid) and a second flexible wall which is deformable by the flexible or rigid wall member of a second testing device. The housing of the first testing device is filled with a gaseous or liquid fluid whose pressure is monitored by one or more gauges or risers, and a further instrument is provided on or in the second testing device to indicate the position of the wall member. The scale of the further instrument is calibrated in units of pressure in such a way that the tension of the eyeball can be read directly off the scale when the gauges or risers indicate that the deforming work upon one of the flexible walls is the same as that upon the other flexible wall.

Abstract: A method is provided for testing the ability of a subject to visually perceive contrast between adjacent fields of different luminance. The subject is presented with a series of visual test patterns, each one of which includes at least two fields of differing luminance resulting in a contrast edge at the interface between the fields. The subject's ability to perceive the edge between the fields is monitored. A series of different test patterns are presented electronically to the subject on a computer-controlled screen which includes one field of constant or fixed luminance and one field of variable luminance. The luminance level of the variable field may be predetermined and varied by the computer in one protocol or controlled by the subject using a subject operated control device as an alternative protocol.

Abstract: Threshold values which are ascertained during successive static perimetric examinations of the visual field of a subject by presenting variable-intensity stimuli to selected points of a test field are permanently recorded in the form of a single graphic display. The printer which makes the permanent record is connected with a computer which controls the sequence of presentation of stimuli during each examination. If the points of presentation of stimuli overlap, the computer ascertains the arithmetic mean of corresponding threshold values which are ascertained during successive examinations or subtracts one threshold value from the other (corresponding) threshold value. Such modified threshold values are also displayed on the record, together with threshold values which are interpolated by the computer between those threshold values which are ascertained during perimetric examination.

Abstract: A method of static perimetric examination of the visual field of a subject involves presenting to the subject a plurality of spots of light of predetermined stimulus values which constitute a group of statistically ascertained mean thresholds for the age group of the subject. Such light spots are presented in a test field in accordance with a randomly selected pattern which is determined by a computer. The computer records the threshold value of each spot and modifies the corresponding stimulus value of the group by replacing it with the threshold value. The modified group is used for presentation of light spots to the same subject during a future test.