Kowa Company Limited

Yoshikatsu Suzumura

Takuya Hara

Satoshi Shimada

Kosuke Ito

Tetsu Tanigawa

Hisao Ishigaki

A perimeter performs a kinetic visual field examination on the basis of a response as to whether a subject visually recognizes a displayed stimulus for kinetic visual field examination. The stimulus is displayed a series of times on an inner surface of a visual field dome. An operation is performed in which the subject is made aware of an operating sound of the perimeter while no stimulus is actually displayed. The operation is performed at a predetermined frequency during the display times of the stimulus, and a duration of the operation is determined in accordance with a response time by the subject to the displayed stimulus. The reliability of the kinetic visual field examination is evaluated on the basis of the response of the subject in the performed operation.

Perimeter

When a Landolt ring optotype is presented in a visual acuity testing unit, an examinee answers a position of a slit of the optotype through an operation of a joystick lever or the like. If an examinee gives a right answer within a standard time at a first presentation of optotype, examination at a higher visual acuity grade is executed by presenting a smaller Landolt ring optotype. In case of a right answer over the standard time, reexamination at the same visual acuity grade is executed twice at the most. If a right answer is given at least once, examination at a higher visual acuity grade is executed. In case of a wrong answer within the standard time at a first presentation of optotype, reexamination at the same visual acuity is executed only once. If the right answer is given at this reexamination, examination at a higher visual acuity grade is executed. Reexamination is thus executed, so that the result of the examination is correct. In addition, the examination time can be shortened since necessary number of times of reexaminations is minimum.

Ophthalmic testing unit and ophthalmic testing equipment

A perimeter has an optical projection system that projects a target spot on the inside surface of a visual field dome. The position at which the target spot is projected is controlled electronically. Input devices are used to input control information to control the target spot projection position and to record patient response information. A display means provides feedback display of the control information and patient response information, and also functions as an input screen via which the control and response information is input.

A perimeter has an image input for inputting eye fundus image data and a display device for displaying an eye fundus image in accordance with the eye fundus image data inputted by the image input. A prescribed area of the eye fundus image displayed on the display device is designated by a designating device. A field of vision of only the prescribed area of the eye fundus image designated by the designating device is then measured by a measurement device.

A vision tester comprises a slide projector for projecting a visual indication chart onto a curved display screen via a mirror rotated by a motor. The center of curvature of the curved display screen substantially coincides with the subject's eye. The rotation of the mirror causes an image of the visual indicator to be moved across the screen in a specific direction. When the subject provides a response to the moving image, the speed of image movement at the time of the response is detected and stored in a memory. The average of a plurality of such measurements is used to determine the subject's dynamic visual acuity.

Vision tester

In an ophthalmologic apparatus comprises an illumination optical system for directing illumination light onto a prescribed point of an eye under examination, and an observation optical system for observing an image of the prescribed point of the eye under examination formed through an object lens. The object lens is movably supported along its optical axis between a first position at which the image point falls at its object point and a second position at which the prescribed point of the eye under examination falls at its image point. As a result, there is a change in the conjugate relationship so that a sharply focused image can be observed when the object lens is at either position thereby making it possible to observe sharply focused images of different magnifications simply by moving the object lens.

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Hamamatsu, Japan

Yoshikatsu Suzumura