2 1,852,837 is adapted to rest a(rainst the observer's forehead to steady the instruinent durii-i(r the observation. The fixation targets 2 ,in@d 3 are placed on opposite sides of the siglit openin(r 16 at a position approximately 25 niillimeters from the center of the si,ht oneniii-. This distance between the ceiiters of the cliarts aiid the siaht opening wis fo-Liiid to be the most 10 comf@'rtable and efficient @ind at the saiiie time -ives a relatively small of fixatioii. The fixation targets 2 - ,iid 3 ,ire formed by placing ,t rotatable disc 19 iii a hotisi,,)cr @@6 havino, a cut away -winclow portiop. 21 f ormeci 15 therein. The disc 19 is providecl witli a series ,if different fixatioi objects, eacii of which is S(@le.etii,ely alignable )vith the -Nvindow 21 by rotation of the disc 19. A sprino, clip 22 which engages suit@t-ble rece@-@ses foriiiecl "ii 20 the disc 19 is aclat)ted to hold the fix,,ttion object in ali,- ninenf ivith the ivitdow 21. The method of operatiOTI of the iiistrumeiit is as follows: If t,he ri@,,Iit. eye is to be e--@aiiiined the patient is told to fi.-z both eyes on the 25 fixation target on the left of the ipstriiiileiit and when testitio, the left eye, vice vers,,t. which fixes both of tile p,,ttieint's eves wli;il@ the eye under test is be'iig exan-iii,,ed, tlius providin(y binocular fixatioii. With the t-",o 30 targets arran(yed oi-ie on each side of the axis of the instrument, the eie is niade to look -,tt a slight inclination to the Iiiie of thc@ proje,-t@d light which permits the 1,,(,Yht to be projected into the eye aloii-g the axis of the crys35 taline lens, which will eliiiiir-ate all f,,Ilse astigmatism. From the foregoinu description it will be seen that we halile PIIOI'ided a simple anci eff@,cient instrurnent and effective means for e,,tr40 ryng out all the objects of the -L-,iv,-ntioii. @aving described our iiivei-itioti, v.7e eliir@i: 1. In a, device of the el,laracter describe,,I, an instrument head havinty two sep,,irately rotate,ble fixation objects oi-,e on each side 45 of the head and rotat@ble in the plane of said head, a source of li(yht and me,-ins on the instrument head for directing liglit fi.@oi-n saici light source for illuminati,ng the fixation objects. 50 2. Iii a device of the character described, an instrument liead haviii(y t-,vo rot,,itable qxation objects one on e,,tch side of the head, a source of light, a i-eflector acljacept the top of each fixation object and in line -",itli 55 and adapted to reflect liaht from the lioht source to illuminate tlile A@ation objects ancl means on the iiistrument liead for selecti-vel,7 shutting off the illumiiiation of said fix-,ttion objects. 60 3. In a device of the ebar,,icter described, a source of light, me,,ins for directin(r l@"ht from said light sotirce to an object to be examined, a pair of rotatable test indicators one on each side of the li-ht clii!ectiiig means 65 zn and mouiited for rotation in the same plane and a reflector associated with each of the rotatable test indicttors for indirect illumination thereof by i.Ilumination from said light source. 4. In a device of the charact-er described, 70 a source of illtimination, a. member having a light passa,-eway leading frorn the source of illumiiiation and having openings intermediate its ends, means aligned with the liaht passageway for directing Eght to ali 75 object to be tested, a pair of fixation objects pi@,otally moiiiitcd one on each side of the light directing means, and for rotation in the siiiie plane and means ali,-ned -,vith the openings iii the passageway for indirect illumi- 50 nat;loii of the rotatable test objects from light passing throu,-h said (peniii-as. 5. In a device of the cha@acter descriw, a source of illumination, a member havin- a light passageway leading from the souree 85 of illumination aiid havino', openino-, intermediate its edds, a reflector support Gn the light passa(yeway, a reflector on the support ali,-ned with the light passa-eway, R pair of fixatioii objects pivotally moi@nted on the sur@- go port one on each side of the reflector .4nd for rotation in th.e plane of the stipport and means associated with the openifn_" in the passageway for directing light rom the source cf illtimination to illuminat@e the fixeltion 95 objects. 6. In a device of the character described, a source of light, a i-nember having a light passagewa leading from the source of light and havin- transverse openings in the side 100 walls thereof, a reflector support carried by the lioht passageway member, a re&ctor on the support, and alio,,ned with the passageway, rotatable test characters carried by the reflector support and for separrtte rotat-ion 105 on each side of said reflector and means Pdiacent each of the rotatable test characters and in line with light coming from the transmrse openings for reflecting the said light on to the rotatable test characters to illuminate the 110 same. 7. In a device for throwing a beam of light, a source of light, a member having a light passagewav leading from the sotirce of li,-ht and having transverse openings in 115 the side walls thereof, a reflector support earried by the light passageway metnber, a re@. flector on the support, and aligned with the p.,,issageway, rotatable test characters carried by the reflector support for separate ro- im tation on each side of said reflector, a shield plate over the test characters and having a window throuoh wbich the characters may be seen, reflectors over the windows and in line of the light coming from the transverse 125 openings of the passageway for reflecting said light onto the rotatable test charaeters visible at the windows to illuminate the same, and nieaiis for selectively shutting off the 130 liglit from said test characters.

8. in a device of the ch@racter described,@ a source of light, a member having a light pa:ssao-eway leadino, fi-om the source of light an,d having transverse openiligs in tl-ie side 7alls thereof, a- reflector sup ort carried by p the light passageway, member and aliomed with the pass,ageway, a reflector on the support rotatable tes'u characters carried by the reflector support for separate rotation on 10 each side of said reflector and in the plaiae of the reflector support and light reflecting means adjacent each of the rotatable test characters, and in Iiiie wit-h the liglit coming from the transverse openings for reflec,ting 1 the said light onto the rotttable t6st characters to illuininate the same. 9. In a device of the cha;racter described, a @,ource of light, a mei-nber h.%vino, a liolit passageway leadina from the source @f @ light 2o and havini@ transyerse openino@s in the sicle walls thereof, a reflector sup ort cai7ried by the lioht@ passageway member, and aligned with the passagewav a reflector on the support, rotatable test characters carried by the reflector support for separate rotation on each s;.de of said reflector and in the plane of the reflector support, light reflecting means adjacent each of:the rotatable test characters and @in line with li--ht comin-- froin 3o the transverse openings for reflectin-g the sa.:id liglit onto 'Uhe rotatable test; characters to illuminate@ the s-,tme @and means for seleetively shutting off the light from said te.st characters. 35 DANIEL DESMOND. NELSON M. BAKERI 40 45 50 60 05

17 Patented,Apr.,15,:!Og@@,, i,8529837 .VNIT@ED, STATEIS@ PATENT@ OFFICE@. DANIEL DESMOND AND@ NELSON m.. 33AiKER, or @: soUTHBRIDGE, 1YJIASSACHUSETTS, AS-@ SIGNORS TO AMERICAN OPTICAL COMPANY, OF SOUTHIBRIDGE, MASSACHUSETTS, A VOLUNTARY ASSOCIATION OF MASSACHUSETTS EYE EXAldINING INSTRUXENT Application.filed January 13, 1930. Serial No. 420,442. This invention relates to improvements in instruments for examining the eye and has pai-ticular reference to that type @gf instru-. ment wherein @: the eye under, examination is illuniiiaated for observation. The principal object of the invention is to provide an instrument to obtain ophthalmic corrections@of the eye objectively, that is by exann nationi without asking quest-ions of the 10 patient. A-nother object of the invention is to provide, means whereby the correction may be obta'med as nearly as possible along the visual axis of the patient's eye. 15 Another:object of the invention is to'provide means to.obtain the correction with the least possible amount of: f@ise asti(,Ymatism. Another object is@ to provide two separate - mproved fixation members to hold the 20 patient's attentioia and to provide improved means. for illuminating the members and for shutting o:ff the :illuriaination@ selectively therefrom when either of the said' flxation 2' Members is not in use. , Another object is@to position the fixation members relative to the line of observation of the, examiiaer so that the most comfortable, and,lefficient fixation:may be obtained. Other objects;@and advantages of @the m30 vention will become @apparent from the, following desbription taken,@in conn'e6tion -with the accompanyiia drawings, and it -will be 9 apparent, that many @ modifications and cha ges' may be made in the details of con35 II structi,on and 'arrangeiiaent of parts wilth-, out departing from the spirit of the invention as expressed in the @ accompanying claims. We, therefore, do not wish to @ be 40@ limited @to the exa,-t details shown and described, @as the preferred form onl,y has been shown by wa of illtistration. y The aceuracy, of ophtlialmic lenses has been developed to a very high degr6e both in the 45 theory of desion,.ai@d iia, the m4echanical proeessts of. mak@.ng them. The art of examinthe eye has also develo-ped gTea-tlY dnd iltngis therefore, the rime object of our inp veiaibioii to provide an impfoved instrument 50 to increase th@ accuracy @ and efficiency of eye testing, particularly in connection with@ th6 elimination of fals asti,,:,-mati e SM. Referring.to the dra-wings: Fi-u. I is a perspective view of a retinoseope emb@'dying, the invention showiiig -,t portion a5 of one of the. reflecting niembers cut away.@ Fi g. II is a front view of the head of the instru ment. Fig. III is a er oss section on line III-III of Fio,. II., 60 Fii IV is an enlarg6d cross segtion on line IV-IV of Fig. II.@ Ref erring to the drawings wherein similar characters of reference indicate corresponcli nu parts throlio-hout, the invention con- 65 sists broadly of a riiiioseope head I having two fixation targets 2 and 3 arranged to be selective ly illuminated @by th6 reflecting means 4 and lamp 5 supported by the handle 6. The retinoseope head I comprises a light 70 condti cting ttibe '7 Provided At one eiid with a conde nsing lens .8 and @at the opposite end with an enlarged threa(led light receiving cham ber 9. The light receiving chamber 9 is adapted o fit over the lamp 5 and be 7c) thread edly coniiected to a thread'ed neck 10 forme d on the handle 6. The tiibular meraort Plate 11 on 12 and 13 the e reflectors 4 are 80 directn ly in I e w 'light pas ough suit-@ able forme d tube 7 and are a reflect light to illuminate the targ e shutter 1 5 positioned 6n the 815 tubular member 7 is adapted to, be r6tated to open or close the openin- 14 on either side -he t-Lib 7 to c trol @h Of t e on e illumination of each target. A suitable opening 16 formed in the sup 9( port plate 11 provides means whereby the observer may view the eye to be exan-iined.4 Positioned on the plate support 11 in@ line with the axis of the sight opening 16 and aiis of the light conducting tube 7 is a transpar-: f)-5 eiit or silvered reflector 17 th@ough which the observer may ma ke his exaininatioii and, by means of which lights coming from the lamp 5, may be reflected into the patieiat's eye. Aheadrest!8attachedtothesupportil 100