Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Patent
1995-10-20
1997-11-11
Mai, Huy
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
351247, 351206, A61B 310, A61B 300, A61B 314
Patent
active
056869819
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a measuring and inspecting device for ophthalmologic use which inspects the condition of an eye of a person for fitting a contact lens. More particularly, it relates to a measuring and inspecting device for ophthalmologic use which inspects the relationship of relative positions between a contact lens being put on and a pupil which receives the contact lens.
BACKGROUND ART
Conventionally, the relationship of relative positions between a contact lens and a pupil has been decided by an inspector's subjectivity while utilizing a slit lamp biomicroscope. Therefore, it is difficult to measure the relationship of positions quantitatively, and there have not been developed any devices especially adapted to perform this function.
On the other hand, contact lenses exist in which the thereof is not a uniform spherical surface but is, instead, an aspherical surface, such as an elliptic surface, for the purpose of improving the case of installing or the optical effect of the contact lens. When such contact lens is put on, it is necessary to make a visual axis, that is by line of sight a center position of a pupil, correspond with an optical axis of the contact lens so as to obtain adequate fitting of the contact lens. However, as mentioned above, the relationship of the positions between the pupil and the contact lens has been conventionally determined by relying upon the inspector's subjectivity, thereby, there have been some cases wherein correct prescription, that is, prescription with correct determination of the relationship of positions between the visual axis and optical axis, cannot be made.
Further, when a special lens, such as a bifocal contact lens, as shown in FIG. 4 (a contact lens having two kinds of refractive power), a multifocal contact lens (a contact lens having many kinds of refractive power), and a toric contact lens (a contact lens whose refractive power varies along the circumferencial direction at an interval of .pi.) is put on, precise measurement cannot be done, although the visual axis and the optical axis of the contact lens have to be considered strictly.
The present invention has been made to solve such problem in the conventional method for deciding the relationship of relative positions between the pupil (visual axis) and the contact lens, and it is, therefore, an object of the present invention to provide a device capable of measuring the relationship of the positions quantitatively and precisely to enable correct prescription of the contact lens easily and based on the an objective decision.
DISCLOSURE OF THE INVENTION
A measuring and inspecting device for ophthalmologic use of the present invention comprises: a photographing means for photographing an anterior eye segment of a subject (a person to be examined); a first display means for displaying an image of the anterior eye segment of the subject photographed by the photographing means; a first position-detecting means for processing the image of the anterior eye segment to detect a position of a pupil; a second position-detecting means for detecting a position of a contact lens put on the subject being tested a calculating the means for calculating relationship of relative positions between the pupil and the contact lens based on positions of the pupil and the contact lens detected by the first position-detecting means and the second position-detecting means; and a second display means for displaying the relationship of the relative positions calculated by the calculating means.
Furthermore, it is preferable that the device further includes an illuminating means for illuminating the anterior eye segment of the subject in order to make the outer condition of the eye constant for measuring.
Further, it is preferable that the illuminating means is variable in illuminance in order to enable measurement in which various conditions (i.e. each of the lighting condition of inside of a room, out of doors, lighting at night, or the like) are assumed.
Further, it is preferable that an i
REFERENCES:
patent: 5293533 (1994-03-01), Klyce
Anan Naoki
Hibino Shingo
Ohyama Hiroyuki
Sawano Tadashi
Mai Huy
Menicon Co. Ltd
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