DEVICE FOR USE IN EYESIGHT TESTING

Abstract: An eyesight tester for possibly finding short-sightedness, long-sightedness etc. In the apparatus are included a number of lenses (34, 34a), differing with respect to lens power, embedded in at least one rotationally arranged wheel (24, 26) and located and distributed along an imaginary circle passing through an ocular (36, 38). The power value (for example -3) of each lens (for example 34a) is indicated on the side surface of the respective wheel (24) in such positions relative to the associated lens (34, 34a) that the power value (-3) of each single lens (for example 34a) will appear in a visible position (40, 41) when the associated lens (34a) is in the ocular (36, 38).

Description: DEVICE FOR USE IN EYESIGHT TESTING This invention relates to a device for use in eyesight testing, so-called eyesight-tests, which device constitutes a means of the kind used to test whether a person needs spectacles/contact lenses, and also to determine the degree of short-sightedness, long-sightedness etc., which device comprises a number of lenses varying in power (refractive pov/er) . Conventionally, eyesight is tested by the use of a let- ter chart, the so-called Snellen's chart, by which eyesight is measured in %. Alternatively a standard spectacle case with loose spectacle lenses of different lens powers . An automatic refractor of the type used by opticians, costs about NOK 100 000,-, a price level of a totally different order than that of eyesight testers of the kind that the present invention relates to. In this connection it may be mentioned that some people, including patients with reduced vision or visual defects of various kinds, often have an aversion to the use of large and bulky apparatus, such as autorefractors, ana experience has shown that entirely satisfactory test results may be achieved for, for example, shortsightedness (myopia) , long-sightedness (hypermetropia) , and long-sightedness conditioned by old-age (presbyo- pia) by means of small, inexpensive aids, which may, through moderate modificacions, also be employed in the testing of aberration of the cornea (astigmatism) . The object of the present invention has been to provide a device of structurally simple configuration, which is easy to operate by the user him/herself, while effectively contributing, at the same time, because of its particular configuration, to the achieving of sufficiently accurate measuring results by means for eyesight testing of the kind in question. Said purpose is realized according to the invention, in that a device for eye-testing of the kind specified in the preamble to the following claim 1, is additionally configured so, that it exhibits the features that appear from the characterizing part of claim 1. An eye-tester configured in accordance with the invention, comprises in its most general embodiment, a support and at least one, preferably two wheels supported rotationally in the support and carrying lenses embedded in the wheel or mounted therein, of different pow- ers/refractive powers, which lenses are distributed along a circular path, said support comprising cover elements for receiving and supporting the lens wheel, said cover elements exhibiting an opening positioned on said circular path, which the lenses may be brought to correspond with, one by one. At least two partially encased lens wheels are normally received in one support, each wheel being enclosed in essentially two parallel cover elements, the two pairs of cover elements preferably being hinged together, so thaz the support may be folded together to occupy half its area when the eyesight tester is not in use, v/hile at the same time the eyesight tester will be less sensitive to external shocks, impact etc. in this folded, strengthened condition. The hinge axis may extend perpendicular to an imaginary connecting line between the two eye pieces/oculars. Besides the eye piece/ocular positioned on the common circular path of the distribution pattern of the lenses, the centre of said path coinciding v/ith the point of rotation of the wheel, at least one cover element of each pair may have at least one further, transverse hole, recess or similar slot/configuration leading into the adjacent side surface/circumferential por- tion of the wheel, more specifically so that it could correspond with one of a number of specifications of lens power corresponding to the refractive power of the lens located in the eye piece. These lens power specifications may be suitably spaced apart along an imagi- nary circle directly on the side surface of the respec- tive rotary wheel, and appear one at a time in said through hole in one cover element, or they may be positioned individually on projections from the wheel circumference and appear in edge recesses, whereby the specification of lens power corresponds, at all times, with the overlapping lens(es) present in the ocular in each case . Said recess may be formed in the circumferential region of the pair of covers as an edge recess which permits - in addition to the task mentioned above - direct access to the wheel circumference portion of the respective wheel, so that by one finger one may turn the lens wheel in the wanted direction, while one eye is preferably positioned in front of the eye piece of the re- spective half of the support. Each one of a number of specifications of lens powers corresponding to the refractive power of the lens present in the ocular/eye piece in each case, may be carried by a projection extending from the respective wheel circumference, which projection passes, by rotation of the wheel, through a narrow slot between adjacent outer edges of opposed cover elements. This narrow slot extends over part of the circumferential extent of each support half. When the eyesight tester support is provided with two lens wheels, one for the right eye and one for the left eye, the two support halves, each comprising a pair of cover elements and a lens wheel supported rotationally between them, will be mirror symmetric about the hinge axis . By expansion of the eyesight tester according to the invention so that it comprises two wheels in each sup- port half, whereby the possibilities of attachment will be increased so that it will be possible to test for aberration of the cornea (astigmatism) , the circular paths on the two parallel wheels of each support half, along which lenses, differing from each other in power, are distributed, may be positioned either centrically or eccentrically in relation to each other. By eccentric positioning of these circular paths of distribution, it will be somewhat easier to separate the individual wheel at the circumference where they project through their respective recesses in the circumferential region of the pair of cover elements, in connection with the advancement of the respective wheel. In this embodiment, two individual lenses, one from each circular pattern of distribution, may be brought to correspond v/ith one another within the eye piece of the respective support half. VJith the eye piece located on one circle of distribution of one set of lenses, the other should, relative to this eccentrically positioned circle, intersect the former within the eye piece. To allov; the same eyesight tester to be used by several persons who have different distances between the eyes, the two support halves v/ith one eye piece/ocular each, are arranged independently rotational relative to the hinge. For this purpose each support half is formed, along its circumference and over a part thereof, with a groove open radially outwards and engaged by a peripheral projecting strip along the edges of the hinge connecting to the support halves. The groove and the projecting strip is formed mutually complementary, so that along the opposite connecting edges of the hinge, the projecting strip cannot be pulled out radially from the groove of the respective support half, v/hich groove may be closed at its ends. The projecting strip may have a radially inner bulb, which engages the radially inner, widest part of the groove, which joins a narrower groove section ending radially at the circumference. The engagement of the projecting strips in the grooves along parts of the circumferential edges of the support halves, is conveniently subjected to friction on sur- face portions resting on each other, so that the set distance of the eye pieces is kept constant until another person is to have his/her eyesight tested with the same apparatus . By two concentric/eccentric lens wheels in each support half, two holes may be formed in each half for indications of lens powers, one from each hole. One of these holes is located at a distance (radius) from the point of rotation of the associated wheel, different from the corresponding distance (radius) of the other hole. This special embodiment requires, moreover, that the wheels themselves be transparent or at least have transparent portions, so that the indications of lens power of the wheel at the back (relative the ocular/eye) are not covered, but can be seen through the wheel/wheel por- tion in front. These and other details of the eyesight tester according to the invention will become more apparent in the following specification of the different non-limiting examples of embodiments in connection with the accompa- nying drawings, in which: Fig. 1 shows, in perspective, a standard version of the present eyesight tester in its active position, formed of two support halves hinged together, each provided with a rotatable lens v/heel and a stationary eye piece, and an opening arranged thereto for the indication of refractive power; Fig. 2 corresponds to fig. 1, but here the cover of one support half is removed to show the rotatable wheel located v/ithin with a number of lenses of different re- fractive pov/ers, distributed along a circular path adjacent to the circumference of the wheel and concentric therewith; Fig. 3 is a radial section corresponding to the line III-III in Fig. 1 through one support half comprising two cover elements v/ith an intermediate lens wheel; Fig. 4 is a perspective view of the eyesight tester in Fig. 1 in its folded-up, idle position; Fig. 5 shov/s a partially cut support half of a second embodiment, in which the support of the eyesight tester comprises two parallel wheels in each support half, which wheels, in the embodiment suggested in Fig. 5, are mutually centric and identical in size and shape; Fig. 6 shows a radial section through the support half with two wheels according to Fig. 5; Fig. 7 shows a view of a third embodiment, seen straight from the front, this embodiment also provided with two lens wheels in each support half, but here the two wheels are placed eccentric to one another, so that it v/ill be easier to operate the projecting circumfer- ential portion of either v/heel, without touching the projecting circumferential portion of the other wheel; Fig. 8 is a radial section generally corresponding to Fig. 3, but showing the internal configuration of one support half of the embodiment according to Fig. 7; Fig. 9 is a radial part sectional view along the section line IX-IX in Fig. 4; Fig. 10 is a part sectional view, corresponding to Fig. 9, on a larger scale, and shov/ing an embodiment with two parallel lens wheels; Fig. 11 corresponds to the front view according to Fig. 7, but shows a fourth embodiment with two eccentrically arranged wheels in each support half, the circumferences of the wheels being provided with projecting, rounded tongues which project individually in the area of the respective edge recess in the circumferential portion of the pair of covers; Fig. 12 is a front view corresponding to Figs. 7 and 11, but shows a fifth embodiment, in which there are formed in the front cover element two through holes for the indications of lens power, which embodiment assumes that at least the front wheel or portions thereof is transparent, so that the indications of lens power of the wheel behind, passing their hole one by one, are not covered. Reference is made to the drawings, first to Figs. 1 - 4 which illustrate a first embodiment of the eyesight tester according to the invention, whereby one can test for short-sightedness and long-sightedness, for exam- pie. By means of the eyesight tester according to the two following embodiments, in which each support half has two wheels arranged thereto with lenses of different powers, one may for example test for aberration of cornea. These embodiments will be discussed later in connection with Figs. 5 - 8. In Figs. 1 - 4 the reference numerals 10 and 12 indicate two support halves hinged together, each comprising a pair of cover elements 14, 16 and 18, 20 overlapping in pairs. This shared hinge structure is defined by 22. All these main parts may be produced from suitable plastic materials. The hinge may have two stable positions, one open active position, Figs. 1 and 2, and a folded, inactive position, Fig. 4. In its folded inactive position the support structure of the eyesight tester occupies minimal space and is less vulnerable than in its unfolded condition. Between the two cover elements 14, 16 and 18, 20 of each support half 10, 12 are rotatably supported wheels 24 and 24, see in particular Fig. 2, projecting from the cover elements 14, 16 and 18, 20, respectively, in the radial direction by a wheel circumference portion 24a and 26a, respectively, through a recess 28, 30 in the common circumferential area of the cover elements overlapping in pairs. Each wheel 24 or 26 has the form of an annular specially profiled disc, Fig. 3, whose inner circular circumferential surface is formed with a circular groove 31, which is engaged, in a glidingly displaceable an- ner, by a complementarily formed bulb 32 on an adjacent internal hub, Figs. 3 and 8. Lenses 34 differing in refractive powers are distributed along an imaginary circle which is centric with respect to the axis of rotation 24A, 26A of the v/heel 24, 26. Each support half 10, 12 has an eye piece, indicated by 36 and 38, respectively. Fittings around each eye piece are exclusively of an aesthetic nature and without any technical significance to the present invention, each hole 36, 38 representing the most suitable point on the eyesight tester for placing each eye in the testing of eyesight right opposite, for example individually, a number of lenses 34, 34a whose powers/refractive powers differ from one another, so that each set of lenses of one wheel may comprise lenses of steps of 0,5 dioptres. From 0 to -5 dioptres on one half of the wheel - 180° - and from 0 to +5 dioptres on the other half of the wheel, all together for example 22 lenses distributed along the circumference of one wheel. In addition to the lenses 34, 34a there should be an opaque but translucent area 42, 44 corresponding to a lens area in size and location, so that it will be possible to block one eye. In the shown embodiment of the eyesight tester, the lenses 34, 34a should conveniently be embedded in the respective wheels 24 or 26, see in particular Fig. 3. Both the wheel 24 and the lenses may possibly be moulded of the same material . A common feature of tv/o further embodiments of the invention consists in the use of two overlapping wheels 24, 24b in each support half of the eyesight tester ac- cording to the invention, v/herein the two wheels 24, 24b are independently rotatable relative to one another, and - in Figs. 5 and 6 - arranged centrically to one another. Thereby tv/o lenses 34 - one from each of the two wheels - may be brought to overlap one another within the eye piece 36, for example with the purpose of testing for aberration of the cornea. In the embodiment according to Figs. 7 and 8 the two wheels 24, 24b, which partially overlap one another within one support half of the eyesight tester, are supported eccentric to each other. This provides advan- tages in the advancing of one wheel relative to the other by the projecting outer circumferential portion of the respective wheel, in that by this eccentric positioning of the wheels, it will be more difficult to mistake their projecting peripheral operating portions, where recesses are formed in the common circumferential region of the pair of cover elements. As appears from Fig. 7, one lens distribution circle will have to intersect the other (eccentric) circle within the respective eye piece 36, 38. In the tv/o embodiments last mentioned, Figs. 5 and 6 and 7 and 8, respectively, the same references have been used for identical and similar parts, compared to the parts of the preceding figures 1 - 4. In one possible embodiment one v/heel may comprise 22 lenses 34, 34a, while the other wheel may be used to test for example for aberration of the corneas, wherein the refractive power of the lenses may vary from 0 to -5 dioptres with steps of for example 0,25 dioptres. In use the relevant lens v/heel is turned until the lens, for example 34A, through v/hich one can have the sharpest vision with the eye positioned at the eye piece 36 (or 38) . The lens power is read off in the hole 40 (or 41) and may be for example -3 for the lens 34a in the eye piece 36. It will be understood that the wheel surface 24, which appears from Fig. 2, will be marked with the lens power values (such as -3 for 34a) , which will appear in the small hole 40 (or 41) while, at the same time, the associated lens 34 is located in the eye piece 36 (or 38) . The embodiment of the eyesight tester according to Figs. 5 and 6 or Figs. 7 and 8 may be constructed for a way of operating, in v/hich the uppermost v/heels 24b, 2βb are first set to pov/er 0, after v/hich the lowermost wheels 24, 26 are set to the best pov/er first, corrections possibly being made later to test for aberration of the cornea, by adjusting the uppermost v/heels 24b, 26b until vision is optimal. Then the result is read off. The eyesight tester may possibly be manipulated by the user, who may spend a very long time carrying out the test, which may also be extended to comprise testing of depth vision, colour vision etc. With a magnifying lens (not shown) in the ocular ( eye piece v/ith lens, for example 36, 34a) it v/ill be possible to reduce the size of the lenses of the wheels and obtain greater accuracy in the measuring v/ith steps of 0,25 dioptres. In Fig. 9 which is a radial sectional viev/ along the line IX-IX in Fig. 4, there is shown a possible ability of the circumference of each of the support halves 10, 12 to rotate relative to the hinge 22, along a suitable continuous part of the circumference of said support halves. By such a rotatability the two eye pieces/oculars 36, 38 may be brought to be mutually approaching/separating, for an eyesight tester to be suited for several persons of different eye distances. An elongate, curved projecting strip 44 extending along each connecting edge of the hinge blades, has an outer thickened part, which displaceably engages, v/ith friction, a radially inner groove portion of a complementary cross-sectional form, of a groove 46 with the cross-sectional shape of an inverted T, formed between a pair of cooperating cover elements 18, 20, at the circumference thereof. The groove 46 may have closed ends. The projecting strip 44 of the hinge 22 engaging the groove 46 cannot fall out of the groove 46, and the rotatable connection between the hinge on the one hand and each of the support halves 10, 12 on the other hand is thus permanently connected. By clockwise rotation of the support half comprising the pair of covers 18,20, Fig. 4, the ocular/eye piece 38 v/ill move av/ay from the hinge axis 22A. So v/ould the ocular 36 of the pair of cover elements 14,16 by anti-clockwise rotation, in the unfolded position, Fig. 1, resulting in an increased distance betv/een the oculars 36, 38. Fig. 10 shov/s a partial cross-sectional viev/ on a larger scale, corresponding to Fig. 9, in v/hich the support half 14,16 encloses two coaxial lens wheels 24, 24b, and in which the lenses, which are indicated by 34, 34a, are embedded in the respective wheel 24, 24b near the wheel circumference. The joined circumferen- tial portions of the cover elements 14, 16 are formed with a groove 46 with the cross-sectional shape of an inverted T, which is displaceably engaged by a complementarily shaped portion 44 of the hinge 22. In the embodiment according to Fig. 11 there are ar- ranged, in each support half 10, 12, two wheels 24, 24b and 26, 26b, the wheels of each pair of wheels being arranged eccentric to one another. As in Fig. 7 each support half 10 and 12 are formed with two edge recesses, 23,28b and 30,30b, respec- tively, at their circumferences. Each wheel 24, 24b, 26, 26b is provided with a number of radially projecting tongues, projections 48, 50, 52, 54, of which one can be seen in each edge recess, 28, 28b, 30, 30b, respectively, each one carrying an indi- cation of lens powers, indicated only for the projection 50, indicating -3, corresponding to one of the lenses located in the eye piece 36. These radial projections are carried by the circumference of the respective wheel 24, 24b, 26, 26b, and do not project beyond the outer circumference of the respective support half 10, 12. In Fig. 12, in a front view corresponding to Figs. 7 and 11, is visualized a further embodiment in which there are formed, in each front cover element 14, 18, two through holes 40, 40a and 41, 41a to disclose the lens power indications on the outv/ard v/heel surface, corresponding to the mutually overlapping lenses of two wheels, made visible simultaneously in the eye pieces 36, 38. Thereby, the front wheels 24b and 26b must be transparent, either entirely or in the areas of the imaginary circular paths of distribution of the rear wheels 24 and 26, along v/hich are placed the lens pov / er indications of the v/heels last mentioned, and which must not be covered and made invisible by the front wheels 24b and 2βb.

Claims: C L A I M S 1. A device for use in the testing of eyesight v/ith the purpose of possibly finding short-sightedness, long-sightedness etc., in the form of a simple means, a so-called eyesight tester comprising a number of lenses (34) of different refractive powers, which may be brought by an ocular device (36; 38) into position in front of the eye to be tested, c h a r a c t e r i - z e d i n that the device comprises a support (10; 12) formed for rotationally supporting at least one v/heel (for example 24b) of a preferably round circumference, along v/hich said lenses (34, 34a) are positioned, distributed along at least one imaginary circle; that said ocular device (36, 38) is located on this imaginary circle, so that one lens (34, 34a) of the v/heel (24b) /each wheel (24, 24b) is positioned at a time v/ithin the ocular device (36, 38) by stepped turning of the wheel (24) ; and that provisions have been made to make visible a lens power indication (for exam- pie -3) on the v/heel (24b) /each wheel (24, 24b) corresponding to the lens (34a) /the mutually overlapping lenses present in the eye piece/ocular (36, 38) , which lens power indications are carried by the respective wheel, preferably distributed along imaginary circles. 2. A device according to claim 1, c ha r a c t e r i z e d i n that in one cover element (14, 16; 18, 20) of each support half (10, 12) there is formed a through hole (40; 41), whereas the wheel (24, 24b, 26, 26b) located within, carries a scale of the lens power/refractive power values (for example -3, Figs. 2 and 11) of the individual lenses (34, 34a), which scale is positioned so in relation to the associated lens (34a) that v/henever the lens is within the ocular de- vice (36, 38) , its pertaining power indication (-3) is brought to correspond v/ith said hole (40; 41) . 3. A device according to claim 2, c h a r a c t e r i z e d i n that each support half (10, 12) encloses two wheels (24, 24a and 26, 26b), and that the front cover element (14, 18) thereof is formed with two holes (40, 40a and 41, 41a), the front wheel (24b, 26b) being transparent, either completely or partly, so that the lens power indications of the v/heel at the back is not covered, and that the two holes (40, 40a and 41, 41a) of each support half are located at different distances from the point of rotation of the respective v/heel . 4. A device according to claim 1, c ha r a c t e r i z e d i n that the circumference of the wheel or each wheel (24, 24b and 26, 26b) is provided v/ith radially projecting projections (48, 50, 52, 54), which carry a lens pov/er indication (for example -3, Fig. 11) each, and which appear in said edge recesses (28, 28b, 30, 30b) simultaneously v/ith the appearing of the lens(es) in the ocular (36, 38). 5. A device according to claim 1, c ha r a c t e r i z e d i n that the two halves (10 and 12) of the eyesight tester support (10,12) are hinged together, said hinge (22) exhibiting flexibility for the support to be folded about the axis (22A) of the hinge, so that the two support halves (10 and 12) essentially overlap one another in their folded, inactive position. 6. A device according to claim 2, c ha r a c - t e r i z e d i n that the hinge (22) has two stable positions, one open position in which its tv/o hinge parts are in the continuation of one another, corresponding to the position of use of the eyesight tester, and a folded position in which the hinge parts as v/ell as the support parts (10, 12) mainly overlap one another. 7. A device according to any one of the preceding claims, c ha r a c t e r i z e d i n that the lenses (34, 34a) are embedded in the respective v/heel (24, 24b, 26, 26b), and that each support half comprises a pair of cover elements (14, 16 and 18, 20) between v/hich at least one such lens v/heel is rotationally supported. 8. A device according to claim 4, c ha r a c - t e r i z e d i n that each v/heel (24, 24b, 26, 26b) has the shape of an annular disc, v/hose inner circumference is formed with an circular groove (31) , in v/hich circumferential bulbs (32) or similar formed on a central, internal hub-like portion of the respective support half (10 or 12) glidingly engage in a guiding and displaceable manner. 9. A device according to claims 4 and 5, c ha r a c t e r i z e d i n that each pair of covers (14,16 and 18,20) is formed in a common outer circumferential region, with at least one recess (28; 30), which extends over a part distance and through which a corresponding outer circumferential portion of the respective wheel (24, 24b, 26, 26b) projects freely, so that it can be influenced by one finger, to turn the wheel in a desired, individually independent direction of rotation. 10. A device according to any one of the preceding claims, c har a c t e r i z e d i n that between two cover elements (14, 16 and 18, 20, respectively) of a pair, there are arranged at least tv/o essentially parallel lens-carrying v/heels (24, 24b and 26, 26b). 11. A device according to claim 7, c h a r a c t e r i z e d i n that said two imaginary lens distribution circles overlapping each other entirely or partly, pass through the ocular device (36, 38) . 12. A device according to claim 8, c h a r a c t e r i z e d i n that said two imaginary lens distribution circles on the v/heels (24, 24b and 26, 26b) enclosed within one and same pair of cover elements (14, 16 and 18, 20) extend essentially centric to one another. 13. A device according to claim 8, c ha ra c t e r i z e d i n that said two imaginary lens dis- tribution circles on wheels (24, 24b; 26, 26b) enclosed within one and same pair of cover elements (24, 16; 18, 20) are placed eccentric to one another. 14. A device according to one or more of the claims 2 - 10, c h a r a c t e r i z e d i n that each support half (10, 12) is rotationally connected to the hinge (22) , so that the distance between the oculars/eye pieces (36, 38) can be changed. 15. A device according to claim 11, c h a r a c - t e r i z e d i n that each support half (10, 12) is formed, at least over a part of its circumference, with a groove (46) open radially outwards, which has a larger v/idth at its bottom than at its opening at said circumference, and that in the groove (46) there is displaceably engaged a correspondingly shaped projection of the edges of the hinge (22) connecting to the support halves (10, 12).

Inventors: STANGELAND ROLF, STANGELAND, ROLF
Applicants: STANGELAND ROLF, STANGELAND, ROLF
Application year: 2000
Main classification: A61B3
IPC codes: A61B3