US1467500A - Astigmatic and visual acuity apparatus - Google Patents

Description

sept. 11, 1923. 1,467,500

W. P. REAVES ASTIGMATIC AND VISUAL ACUIIY APPARATUS original Filed June 3o. 1920 2 sheets-sheet 1 W. P. REAVES ASTIGMATIC AND VISUAL ACUITY APPARATUS Sept. 11, 1923. 1,467,500

Original Filed June 50. 1920 2 Sheets-Sheet 2 Patented Sept. 1l, 1923.

WILLIAM P. nnavns, or eannivseoao, NORTH CAROLINA.

ASTIGMTIC AND VISUAL ACUITY APPARATUS.

, Application filed June 30, 1920, Serial 110.393,143. Renewed February 21, 1923.

To all whom t may concern: Y

Beit known that I, TNrLLIAM I. Rniivns, a citizen of the UnitedStates residing at Greensboro, in the county ofv (ruilford'and State of North Carolina, have inventedlcer'- tain new and useful Improvements in Astigmatic and Visual Acuity Apparatus;v and venience by which the patient is enabled. to

inform the oculist as to the exact position of the blurred field of vision'. y

A. more detailed object of the invention lies in the provision of an indicator adapted t0V sweep over the semi-circle of radial lines common in optical charts, whereby the patient whether illiterate or not, may readily inform the oculist by word or motion'of hand when the arrow points to the most distinct lines.

Other and further objects of the `invention less important than those heretofore Y' i mentioned, will be apparent from the following description, and such details willy he distinctly specified in the claims following such description.

Figure 1 represents an end device as seen by the patient; f

Figure 2 is a similar view but with the indicator and chart removed;

Figure 3 is a side elevation of my'device with the side wall removed; l

In its preferred form my device consistsl of a metal or wooden box 10 having `an open front, which is closed panekof translucent glass 11 of the usual opalescent or milky color so that the mechanism within y the box cannot be observed by the patient.`

A further advantage of this color of glass is to relieve the eye of all strains incident to the use ofclear glass which would not diffuse the light in an even manner.

On the glass pane 11 is delineated a plurality of radial lines 12 five degrees apart forming together a semi-circle each third line of which has a numeral 13 to denote vof, the patient.

view of my .,thenumher' of degrees from the zero mark 14: Centrally 0f these radial linesv are'two letters 16 indicating the next higher chart,

and'fbeneath the semi-circle are` a series of 60 letters, 1T, the thickness olf each of which is exactly .equal to the lthickn'essfcf the radial lines Al2.` I do hereby declare the following to be a The line ythat corresponds to` the astiginatic axis of. the eye of the patient'will 65 after `correction of any myopia or hyperopia 'appear clearer and more distinct to the patientl than the other lines. The oculist, usuall'yxstationed beside the patient at a distance' of about twenty feet from the 'ch-art, 70 I ,draws the indicator to this clearest appearing line in accordance with directions given by the patient by motion ofthe hand,v or

l otherwise. in eye testing, because of the ease 'and conf before the patientseye the. lens thaty cor,

krects `the astigmatism, when all lines will" n 'appearv equally sharp and well defined.

Theoculist now neutralizes` Ithe indicated astigmatism by slipping in the trial frame 'Ihe patientI can now read the. row of let-v 80 tersl 17 which lgives the acuteness of yision It will vbe, understood by those familiar with the art, that in practice the box 10 will contain two, three or four charts', for 85 example, Snellens type aan 302015' butfor convenience of illustration, the `box o is shown with one of such charts, therothers being generally similar. Y l- Iithin the box and parallel to' the base thereof is located -ashaft 20 concentric with the semi-circular'v radial lines 12 and having 95 a bearing 21 in the front glass 11,and a similaibearing 22 in the rear wall. `This shaft 2O carries at a oint nearits rear vend -a wheel 23 to whic is secured by any by means of which the wheel andtherefore Idesired fastenings, such as 24, a cable 25 10 the sha-ft 2O may be rotated about-itsaxisA y in opposition to the effect of .a spring 22, secured at one end tothe shaft 20 and by its free end tothe rear wall 26 of lthe box. 105

I preferably provide a stop 28 on the cord adapted Ato contact with a screw eye 29 to prevent `excess movement of the shaft in one direction and I also provide a similar s'top 30 and a corresponding screw eye 31 on the outside of the box to normally maintain the shaft in such position that the inthe box. This lamp is preferably mounted dicator hereinafter described will point to Zero degrees. In order that the cable 25 may be directed to the oculists position', it is preferably led over a small pulley vwheel journaled in bearings 34 on the side wall of the boX.

Within the box, and as near the shaft 20 as possible, I mount an electric lamp 35 or other preferred source of light in order to illuminate the figures on the front glass of in a socket 36 held in desired position by means of a bracket 37 secured to vthe lower wall by means of screws or'other fastenings passing through the lugs 38 of the bracket. The electric wires 39 for the lamp are connected to the terminals 40 on the outside of the box and the latter may in turn be connected to a switch located conveniently for ktively small white metal stem 43 and an enlarged arrow head 44 preferably of dull blaclnsimilar to the color of the lines 12. The arrow 44,y as illustrated in Fig. 1, is preferably spaced from the stem about 12% degrees so that when'the arrow head 44 is directly over one of the radial lines, as for eX'ample, the 90o one, the metal stem 43 will lie between the 100O mark and the 1050 mark, and since such stem is white it will not affect the vision and will be practically invisible, but the arrow head itself, being black, will stand out definitely on the chart.

The patient is frequently unable to denote to the oculist the exact line that appears most distinct to her vision, owing to her inability to read or decipher the degree marks at the given distance, and for this purpose it is'common practice for an assistant with a wooden pointer to move `the pointer about a semicircle until the desired position is reached. lVith my device the occulist, who is usually about twenty yfeet away, merely pulls the cable 2'5 and brings the arrow to the point of clearest vision with little delay and without the need of an assistant.

Particular attention is called to the fact that with the aid of my device the oculist is enabled to remain constantly at the side of the patientvand at a distance from the chart, thus saving the very appreciable amount of time that would otherwise be consumed in 'traveling to the chart to indicate the line and back to the patient to replace'the trial glass that had been found unsatisfactory.

What I claim is:

l. In an astigmatic chart, a series of radial lines, an indicator pivoted at the center of said radial lines and having a laterally offset end spaced from the stem of the indicator so as to lie between two of the radial lines when the head of the indicator in-v dicates another of said radial lines.

2. In an astigmatic and visual acuity device, a receptacle having an open end, a removable panel of translucent material, a series :of radial lines or marks on said panel, a source of light `within said receptacle adapted to illuminate said translucent panel and to render the radial lines visible, a shaft, an indicator on said shaft having a laterally offset headed end, the distance between the head of said indicator and the stem of said indicator being such that when the head of the indicator is in line with one of said marks that the stem will lie between two of the other marks, and means controlled by the oculist from his position beside the patient at a distance from the panel for rotating said shaft so asto bring the head of the indicator in line with. a chosen one of said marks.

3. In an astigmatic and visual acuity device, a receptacle having an open end, a removable panel of translucentl material of light color, a series of radial lines or marks on said panel spaced apart an even number of vdegrees said marks being of dark color to contrast with the face of the panel, a source of light within said receptacle adapted to illuminate said translucent panel and to render the radial lines visible, a Support n for said light, a shaft supported by said re-v cator is in line with one of said marks that the stem will lie between'two of the other marks and therefore practically invisible to the observer,vand means controlled by the oculist from his position beside the patient at a distance from the panel for rotating said shaft so as to bring the head of the indicator in line with a chosen one of said marks.

WILLIAM P. REAVES.

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