Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Reexamination Certificate
2001-02-09
2001-10-23
Manuel, George (Department: 3737)
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
Reexamination Certificate
active
06305803
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ophthalmic apparatus. More particularly, the present invention relates to an ophthalmic apparatus used in refractive surgery to change (alter) a radius of curvature of a cornea of a patient's eye by corneal ablation.
2. Description of Related Art
There are several types of refractive surgery to change (alter) a radius of curvature of a cornea of a patient's eye by ablating the cornea with an excimer laser beam thereby to correct refractive errors such as myopia, hyperopia, astigmatism and the like. Conventionally, in such types of surgery, the corneal shape, the eye refractive power of the eye and the like are measured before an operation and then the operation is carried out based on the obtained measurement data.
However, in these types of surgery, attention has been paid merely to correction of the refractive power of optics of the eye such that a paraxial focal points is positioned on the retina and quality of the image formed on the retina (influence of marginal rays on the image) has not been taken into account. Therefore, the corneal ablation may not necessarily be carried out properly and patients may not be fully satisfied with their post-operative visions.
In addition, although a radius of curvature of the cornea is properly corrected thereby achieving emmetropization of the optics of the eye, the patient may not always improve the post-operative vision as he expected in case the patient suffers from a disturbance in the nervous system following the retina, the brain or other signal system. Therefore, it is desirable to give sufficient information to a patient and to make him fully understand of the situation before performing surgery.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide an ophthalmic apparatus which allows that corneal ablation is carried out in consideration of quality of an image on a retina, and the post-operative state of the patient's eye is estimated.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, an ophthalmic apparatus used in refractive surgery to change a radius of curvature of a cornea, the apparatus comprises first input means for inputting data about a pre-operative corneal shape of a patient's eye, second input means for inputting data about an intended post-operative corneal shape of the eye, third input means for inputting data about a pre-operative MTF of an ocular imaging system of the eye, and arithmetic means for obtaining an intended post-operative MTF of the ocular imaging system of the eye based on each inputted data.
In another aspect of the present invention, an ophthalmic apparatus used in refractive surgery to change a radius of curvature of a cornea, the apparatus comprises a corneal shape analysis unit which obtains data about a corneal shape of a patient's eye, an MTF measurement unit which obtains data about an MTF of a visual system and data about an MTF of a retina-brain system of the eye, an input unit which inputs data about an intended post-operative corneal shape of the eye, and an arithmetic unit. The arithmetic unit is used to obtain: a pre-operative MTF of the cornea of the eye based on the obtained data about a pre-operative corneal shape; a pre-operative MTF of an ocular imaging system of the eye based on the obtained data about a pre-operative MTF of the visual system and the obtained data about a pre-operative MTF of the retina-brain system; a pre-operative MTF of an intraocular optical system of the eye based on the obtained pre-operative MTF of the cornea and the obtained pre-operative MTF of the ocular imaging system; an intended post-operative MTF of the cornea of the eye based on the inputted data about the intended post-operative corneal shape; and an intended post-operative MTF of the ocular imaging system of the eye based on the obtained pre-operative MTF of the intraocular optical system and the intended post-operative MTF of the cornea obtained thereby.
Yet, in another aspect of the present invention, an ophthalmic apparatus used in refractive surgery to change a radius of curvature of a cornea, the apparatus comprises a memory and an arithmetic unit which performs arithmetic operation in accordance with the program. The memory contains a program therein for obtaining an intended post-operative MTF of an ocular imaging system of the eye based on data about a pre-operative corneal shape, data about an intended post-operative corneal shape and data about a pre-operative MTF of the ocular imaging system of the eye.
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Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Manuel George
Nidek Co. Ltd.
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