Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Reissue Patent
1997-05-07
2001-05-29
Dang, Hung Xuan (Department: 2873)
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
C351S205000, C351S247000
Reissue Patent
active
RE037196
ABSTRACT:
The invention relates to an apparatus and method for determining a prescription for contact lenses. Both soft and hard lenses are known, which may optionally be permeable. However, it was hitherto not possible to determine the appropriate lens accurately by individuals without expertise in the field of measuring and calculating prescription for lenses. The present invention provides a solution to this problem.
For determining a prescription contact lenses the present invention provides an apparatus and method wherein individuals without special education other than operating the relevant apparatus, are able to determine the appropriate prescription contact lenses. In determining the prescription for a lens, in the present case a contact lens, a considerable number of special circumstances may play a part in determining the appropriate lens to be used. In that respect it can be mentioned by way of example the history of the eye involved, including possible eye-operations, the possibility of allergies, any use of medicines, special conditions in the workplace, such as fumes, air-conditioning, chemicals and smoking, and any medical indication which might prohibit the use of contact lenses. The environmental conditions are of special importance for gas-permeable lenses. In order to collect this information, a list of pertinent questions should be filled out by checking with the client. These data should be stored for determining what type of lens should be used.
The apparatus according to the invention comprises in cooperation a refractometer, a keratometer, a vertexmeter, (a meter for determining the strength of spectacle glasses) and a tono-meter for determining the pressure in an eye-ball. In addition a slit lamp can be used for observation of the lens, conjuctiva and blood vessels in order to obtain possible contra-incications. These measurements can be made automatically or manually. Hitherto the data thus obtained were used for calculation of the prescription for the lens. According to the present invention the data from the instruments used are fed automatically into a computer, wherein the data obtained, together with the special information mentioned in the previous paragraph are combined for obtaining the appropriate details of the lens required.
The customary refractometers, keratometers, vertexmeters and tono-meters for use in the present invention may optionally be provided with a print-out feature for printed out the results of the measurement with the specific meter. Hitherto they have not been used in other than a manual combination, that is, that the results are combined and plugged into a relevant formula. According to the present invention, all meters desired are directly connected with a computer, thus avoiding the need of any expertise of the operator other than handling the apparatus involved. Thus the history of all clients can be entered in a simple manner and without errors, as may occur in manual combination, with the possibility of easy retrieval if required.
In addition, the invention provides a method for determining the appropriate lens for an eye, comprising measuring the eye with a refractometer, a keratometer and optionally a tono-meter, automatically feeding the data of these meters into a computer programmed to plug these data into an appropriate formula, preferably in combination with individual data on history, environmental conditions and medical indication, which may affect the selection of the type of Lens. Thus the client will obtain an accurately calculated lens without any risk of either insufficient expertise or errors in carrying out the calculation, as the programme has been screened accurately.
The apparatus according to the invention not only allows carrying out these measurements, but also takes into account deviations of the eyes such as astigmatism and the like. In addition the apparatus is suitable for taking into account any deviations of the eye resulting from use of the contact lens, such as deformation of the cornea, which may demand switching from spheric lenses to toric, i.e. elliptic lenses and vice versa. Alternatively it may be found that special lenses are required which may be toric or which may require manual manufacture on prescription by an eye-doctor.
REFERENCES:
patent: 3290927 (1966-12-01), Gambs
patent: 4796989 (1989-01-01), Fukuma et al.
Dang Hung Xuan
Harness Dickey & Pierce PLC
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