Determining and Marking Apparatus and Method for Use in Optometry and Ophthalmology

FIG. 1 is a perspective view of a embodiment of the apparatus of the present invention shown positioned by a patient adjacent the exterior surface of a spectacle lens.

FIG. 2 is a side elevational view of the apparatus of FIG. 1.

FIG. 3 is a perspective view of a first alternate embodiment of the apparatus of the present invention.

FIG. 4 is a perspective view of a second alternate embodiment of the apparatus of the present invention.

FIG. 5 is a perspective view of a third alternate embodiment of the apparatus of the present invention.

FIG. 6 is a perspective view of a fourth alternate embodiment of the apparatus of the present invention having an attached handle.

FIG. 7 is a perspective view of a fifth alternate embodiment of the apparatus of the present invention.

FIG. 8 is an electro-mechanical schematic view of the apparatus of FIG. 7.

FIGS. 1-2 detail an embodiment of the apparatus 10 of the present invention designed to allow subjective determination of the proper positioning of progressive power or other corrective lenses. As shown in FIGS. 1-2, apparatus 10 may be positioned by patient 14 against or immediately adjacent the exterior surface 18 of a lens 22 contained within spectacles 26. New spectacles 26 frequently include a plane simulator lens which may serve as lens 22, although apparatus 10 may be used in connection with the patient's existing spectacles 26 if prescriptive or other lenses are in place. Alternatively, as disclosed in U.S. Pat. No. 4,206,549 to Gould, lens 22 may be cut or stamped from a sheet of plastic and fitted into or otherwise secured to spectacles 26.

Apparatus 10 includes a light source 30, a marking rod 34, and two marking elements 38 and 42 associated with the marking rod 34 and positioned so that their respective tips 46 and 50 are equidistant from light source 30. The ability of the patient to mark lens 22 at two points equidistant light source 30 forms a significant feature of the invention, as bisection of a real or imaginary line drawn between the two points provides the reference from which progressive power or other corrective lens may be precisely positioned or fitted.

Also included as part of apparatus 10 are frame 54, compartment 58, thumb rest 62, stem 66, feet 70, finger rests 74 and 78, bar 82, and actuator arm 86. As illustrated in FIGS. 1-2, frame 54 may be molded or otherwise constructed substantially in a "U" shape and made of any suitable material such as plastic or metal. Frame 54 also may be designed so that the distance between prongs corresponds approximately to or is slightly less than the average width of lens 22 in order not to obstruct the vision of patient 14 significantly. Compartment 58 forms the bottom of frame 54 and may be used to house a battery or other power source for light source 30. Compartment 58 also may include a depression or other thumb rest 62 as its lower surface in order to allow patient 14 to stabilize apparatus 10 when positioned in his or her field of view.

Extending upward from compartment 58 and housing light source 30 is a thin stem 66. Light source 30, which typically may be a small fiber optic channel or a light-emitting diode (LED), is used as a target for the patient 14. Consequently, as best shown in FIG. 2, stem 66 extends beyond the plane defined by the prongs of "U"-shaped frame 54 so that light source 30 may be positioned against or closely proximate exterior surface 18 of lens 22. Stem 66 also serves to sheathe the electrical connections (which may be made via switch 68) between light source 30 and the power source in compartment 58 and, like frame 54, is designed to obstruct little of the patient's vision.

Feet 70, as illustrated in FIGS. 1-2, may be utilized to assist stabilization of apparatus 10 while in use. Any non-abrasive material such as felt or Teflon having a sufficient coefficient of friction to prevent undesired movement of apparatus 10 may form the surface of feet 70, which may be attached to either or both of frame 54 and compartment 58 and oriented to fit substantially flush with the exterior surface of lens 22. Also designed to assist patient 14 in stabilizing apparatus 10 are finger rests 74 and 78 associated with bar 82, which bar 82 is connected near each end to the prongs of "U"-shaped frame 54 and forms the upper section of apparatus 10. Patient 14 typically places a forefinger on one of finger rests 74 and 78 to counteract the upward force generated by the presence of his or her thumb on thumb rest 62.

Movement of marking rod 34 and elements 38 and 42 is accomplished using actuating lever or arm 86. In one embodiment of the invention consistent with FIGS. 1-2, included within bar 82 is a torsion spring associated with actuating arm 86. Referring principally to FIG. 2, in its unactuated position arm 86 lies slightly above the horizontal plane including the center of bar 82, while tips 46 and 50 of marking elements 38 and 42 rest a short distance from exterior surface 1B of lens 22. When patient 14 presses on arm 86, however, typically with the middle finger of the hand holding apparatus 10, the torsion spring stresses and marking rod 34 moves in an arcuate path sufficient to allow tips 46 and 50 (which may be inked felt, grease pencil, or other suitable devices) to contact and mark the exterior surface 18 of lens 22. Once pressure on arm 86 is released, the torsion spring relaxes and returns tips 46 and 50 and arm 86 to their resting positions.

Although FIG. 2 shows marking rod 34 as rigidly attached to actuator arm 86 at an angle of approximately 90.degree., any appropriate angle may exist between these components. Optimal results likely will be achieved, however, if the travel requirements of marking rod 34 are minimized. Similarly, those having ordinary skill in the art will recognize that actuation means including elements other than a torsion spring may be used to assist forward and return movement of marking rod 34. For example, arm 86 may be designed merely to rotate about bar 82, with sufficient friction existing between arm 86 and bar 82 to require some force to be provided by patient 14 to cause marking rod 34 to contact the exterior surface 18 of lens 22. Marking precision, however, probably will be increased if the amount of force required to be supplied by patient 14 is small.

Operation of apparatus 10, discussed principally relative to the left eye 90 of patient 14 and its corresponding visual axis or primary line of sight 94, may be described as follows. Initially, spectacles 26 should be fitted to patient 14. Although apparatus 10 may be used whether or not spectacles 26 are pre-fitted, adjustment of spectacles 26 after one or both of the lenses 22 are marked may result in improper positioning of the progressive power or other corrective lenses.

Once spectacles 26 are comfortably fitted, patient 14 may grasp apparatus 10 with the forefinger of his or her left hand placed on finger rest 74 and thumb placed on thumb rest 62. Patient 14 then, preferably while standing or sitting and with his or her head in its primary position, fixates (using both left and right eyes 90 and 98, respectively) on a remote target RT such as a chart, picture, or other suitable object located along primary line of sight 94. While fixating on the remote object patient 14 positions apparatus 10 so that light source 30 is located immediately adjacent exterior surface 18 of lens 22 and centered along primary line of sight 94. Once light source 30 is centered patient 14 actuates arm 86, typically with his or her left middle finger and causes marking rod 34 to contact lens 22 at two points along its exterior surface 18. Lens 22 may then be used as a model for creating the progressive power or other corrective lens to be fitted into the corresponding section of spectacles 26.

A similar procedure may be followed in connection with the right eye 98 of patient 14, with the patient 14 typically grasping apparatus 10 in his or her right hand with its forefinger positioned on finger rest 78. Moreover, those having ordinary skill in the art will recognize that apparatus 10 may be modified to allow simultaneous or concurrent marking of lenses 22 associated with both the left and right eyes 90 and 98. Apparatus 10 similarly may be modified so that it clips onto or is otherwise attached to the exterior portion of spectacles 26 if desired. Additional marking elements and tips may be added to, for example, allow triangulation of the reference point for the final corrective lenses. Alternatively, apparatus 10 may be modified so that a single (very thin) marking tip is aligned with the center of light source 30 and thereby is capable of making a single mark corresponding to the exact location of the corrective lens reference point. Light source 30 similarly may be modified so that, for example, it clips to the nasal bridge of spectacles 26 and extends away from patient 14, in which case the patient 14 may view the light source 30 in a distant mirror. In each case, however, apparatus 10 is designed so that a known or determinable relationship exists between the locations marked on lens 22 and the point on lens 22 through which patient 14 aligned light source 30.

Because apparatus 10 is designed to obstruct very little of the vision of patient 14, his or her peripheral vision remains intact and allows binocular fusion to occur, thereby avoiding introduction of accuracy-reducing phoria. Stabilizing apparatus 10, decreasing the amount of force required to move actuating arm 86, and limiting the travel distance of marking rod 34 further improve the accuracy of the resulting measurements by minimizing movement of spectacles 26 relative to apparatus 10 while in use. If the vision of patient 14 is extremely poor when a simulated plane or a non-optimal prescriptive lens is used as lens 22, the remote object on which patient 14 fixates may itself be illuminated or otherwise acted upon to be more easily seen. By minimizing the errors associated with traditional objective positioning devices, apparatus 10 allows the precise location where a power change or other appropriate component of the corrective lens should exist or begin to be obtained merely by bisecting an imaginary or real line drawn to connect the two marks on lens 22 or otherwise determining the relationship between the mark or marks and the point on lens 22 through which patient 14 aligned light source 30.

FIGS. 3-8 detail alternate embodiments of the present invention. Each of apparatus 310, 410, 510, and 610 include a light source and associated marking means and function similar to apparatus 10. Apparatus 310 of FIG. 3, for example, comprises a light source 330, frame 354, compartment 358, thumb (or (middle) finger) rest 362, stem 366, electrical switch 368, feet 370, (middle) finger (or thumb) rest 374, actuator arm 386, and a torsion spring stressed when arm 386 is actuated, typically using the patient's forefinger. Apparatus 310 also includes two marking elements 338 and 342 and corresponding marking tips 346 and 350. Unlike the marking elements 38 and 42 of apparatus 10, however, marking elements 338 and 342 are connected to a pair of marking rods 334a and 334b, both of which are actuated by arm 386 via a flexible cable or other suitable transmitting device. Moreover, each of feet 370 positioned near the top of the prongs of "U" shaped frame 354 houses a trunnion about which marking rods 334a and 334b pivot while guided by tracks 388. Although marking rods 334a and 334b as illustrated in FIG. 3 must travel farther than rod 34 of FIGS. 1-2 to contact the exterior surface 18 of lens 22, their resting positions thereby are a greater distance from the primary line of sight 94 of patient 14.

FIG. 4 details another embodiment of the present invention in which the actuating mechanism includes arm 486, torsion spring 490, rack gear 492, pinion gear 494, flexible cable 496, and trunnions 498. Depressing actuator arm 486 stresses torsion spring 490 and causes the teeth of rack gear 492 to engage corresponding teeth of pinion gear 494. Flexible cable 496 associated with pinion gear 494 transmits the movement, thereby causing marking rods 434a and 434b to pivot about trunnions 498 while guided by tracks 488. Apparatus 410 also includes light source 430, marking elements 438 and 442 having tips 446 and 450 respectively, frame 454, compartment 458, thumb (or (middle) finger) rest 462, stem 466, momentary switch 468 (which also serves as a (middle) finger (or thumb) rest), and feet 470.

FIG. 5 illustrates an alternate embodiment of the present invention having a circular frame 554 and a combined actuator arm and forefinger rest 586. Other components of apparatus 510 shown in FIG. 5 include light source 530, marking rods 534a and 534b, marking elements 538 and 542, marking tips 546 and 550, compartment 558, thumb rest 562, stem 566, switch 568, feet 570, tracks 588, and flexible cable 596. Finally, FIG. 6 details an apparatus 610 nearly identical to apparatus 310 of FIG. 3 to which compartment 658 has been extended to form a handle. To use apparatus 6-0, patient 14 merely grasps handle or compartment 658 in the palm of his or her hand.

Illustrated in FIGS. 7-8 is an embodiment of the present invention in which apparatus 710 utilizes a solenoid 714 to actuate a push rod 7-8 connected via actuator arm 722 and actuator shaft 726 to markers 734a and 734b. Apparatus 710 additionally includes light source 730 (which may include one or more LEDs and, when suitable, be used in conjunction with filters such as different colored cellophane or similar strips) and a fiber optic channel 732 for conveying light emitted from light source 730 to a location central (or otherwise appropriate) to markers 734a and 734b. Also shown as forming apparatus 710 are feet 770 and spring 738 intermediate solenoid 714 and push rod 718.

Electrically connected to apparatus 710 through cable 738 is activator module 742. Module 742 contains power source 746 for light source 730 and a normally open, momentary switch 768 for forming the electrical connection between power source 746 and solenoid 714. Rheostat 750 also may be electrically connected between power source 746 and light source 730 if desired to adjust the intensity of light source 730, and thumb knob 754 may be used to provide power to light source 730 and vary the resistance of rheostat 750.

Apparatus 710 is designed so that its handle 774 may be held by patient 14 in one hand. Module 742 may be held in the other hand of patient 14 or alternatively by the practitioner, decreasing the possibility of apparatus 710 being jarred or moving when switch 768 is depressed and lens 22 marked. With light emitted through channel 732 centered (or otherwise appropriately positioned) relative to primary line of sight 94, switch 768 may be depressed to activate solenoid 714. Solenoid 714 in turn actuates push rod 718, permitting arm 722 to rotate shaft 726 and cause markers 734a and 734b to contact the exterior surface 18 of lens 22. Spring 738 accommodates any overtravel of the plunger of solenoid 714 and permits markers 734a and 734b to retract immediately after marking lens 22.

The foregoing is provided for purposes of illustration, explanation, and description of embodiments of the present invention. Various modifications to and adaptations of the embodiments, including those discussed earlier, will be apparent to those of ordinary skill in the art and may be made without departing from the scope or spirit of the invention. Finally, although the apparatus of the present invention shown in FIGS. 1-8 are designed to be held by patient 14, and allow for precise positioning of corrective lenses when the subjective techniques described above are used, the apparatus may be held by the practitioner or attached to a stationary object if necessary, as when patient 14 lacks full hand or arm function.