Surgery – Instruments – Light application
Reexamination Certificate
1998-06-02
2001-05-29
Shay, David M. (Department: 3739)
Surgery
Instruments
Light application
C606S010000, C606S013000
Reexamination Certificate
active
06238385
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a laser treatment apparatus which irradiates a diseased part of a patient's eye with a treatment laser beam, thereby treating the diseased part of the patient's eye by means of photocoagulation or the like.
In order to treat a para fovea neovascularization formed in the vicinity of the central fovea and due to a disease in which the main lesion is choroidal neovascularization, such as age related macular degeneration, the laser treatment wherein the diseased part is irradiated with a laser beam so that the diseased part is photocoagulated is mainly employed. In this treatment, it is very important to determine the position of the central fovea so as not to affect the central fovea.
Conventionally, the position of the central fovea is determined while fixing the patient's eye to an aiming beam having a circular shape of about 50 &mgr;m. Alternatively, the position of the central fovea is determined in the following manner. After an eye is fixed to an external fixation lamp attached to a slit lamp or the like, an aiming beam is moved (scanned) vertically and horizontally, and it is checked whether the aiming beam can be visually recognized or not.
However, the former method in which an eye is fixed to an aiming beam has a problem in that, since the spot size of the aiming beam is as small as about 50 &mgr;m, an eye of a patient having reduced central visual acuity is unstably fixed to the beam, and hence the aiming beam is moved when the laser irradiation is conducted.
In the latter method, skill is required to correctly determine the position of the central fovea, and therefore it is often difficult to determine the position of the central fovea.
SUMMARY OF THE INVENTION
The invention has been made in view of the above-discussed problems. It is an object of the invention to provide a laser treatment apparatus in which the fixation of a patient's eye can be stabilized, the operator can correctly know the position of the central fovea of the patient's eye, and treat (photocoagulate) the diseased part near the central fovea safely.
In order to solve the problems, the invention is characterized in the following configuration.
(1) A laser treatment apparatus comprising a guide beam forming means for guiding a treatment laser beam to a diseased part,
a laser beam irradiation optical system which irradiates the diseased part with the treatment laser beam is characterized in that the apparatus further comprises: an illumination optical system which illuminates an fundus of a patient's eye; an observation optical system through which the fundus of the patient's eye is observed; a target projection optical system which projects a target for obtaining a position of a central fovea of the patient's eye, to the fundus; and a fixation mark projection optical system which projects a fixation mark for fixing the patient's eye so that the central fovea is located at a predetermined position with respect to the target.
(2) The apparatus is characterized in that the target projection optical system of (1) is used also as the fixation mark projection optical system.
(3) In the laser treatment apparatus of (1), it is characterized in that the target is a cross chart and has a size specifying a region which does not affect the central fovea in laser irradiation to the fundus.
(4) In the laser treatment apparatus of (3), it is characterized in that the target has a size which can be visually recognized by a region of a retina of a patient's eye in which a central fovea is disturbed, the region not being disturbed.
(5) In the laser treatment apparatus of (3), it is characterized in that a scale for specifying a distance is formed in the cross chart.
(6) In the laser treatment apparatus of (3), it is characterized in that a concentric circular mark, or a matrix-like grid line is attached to the cross chart.
(7) In the laser treatment apparatus of (1), it is characterized in that the target projection optical system and the fixation mark projection optical system share a part of an optical path of the illumination optical system or the observation optical system.
(8) In the laser treatment apparatus of (7), it is characterized in that the apparatus further comprises attaching and detaching means for allowing the target projection optical system and the fixation mark projection optical system to be attached to and detached from the illumination optical system or the observation optical system.
(9) In the laser treatment apparatus of (1), it is characterized in that the apparatus further comprises variable magnifying means for varying a size of an image of the mark projected by the fixation mark projection optical system.
(10) In the laser treatment apparatus of (1), it is characterized in that the apparatus further comprises a slit lamp microscope, a surgical microscope, or a fundus camera.
(11) In the laser treatment apparatus of (1), it is characterized in that a color of the target projected by the target projection optical system is different from a color of an aiming beam.
(12) In the laser treatment apparatus of (1), it is characterized in that the apparatus further comprises changing means for changing a color of the target projected by the target projection optical system.
(13) In the laser treatment apparatus of (1), it is characterized in that the apparatus further comprises moving means for moving a position of an image of the target projected by the target projection optical system, on the fundus.
(14) A laser treatment apparatus comprising a guide beam forming means for guiding a treatment laser beam to a diseased part,
a laser beam irradiation optical system which irradiates the diseased part with the treatment laser beam is characterized in that the apparatus further comprises: an illumination optical system which illuminates an fundus of a patient's eye; an observation optical system through which the fundus of the patient's eye is observed; and a target projection optical system which projects a target for fixing the patient's eye, and for obtaining a position of a central fovea of the patient's eye, to the fundus.
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Harino Seiyo
Naito Yasuyuki
Nakamura Hirokazu
Sumiya Toshifumi
Tomita Seiki
Nidek Co. Ltd.
Shay David M.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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