Background of the Invention

The present invention relates to trial frame devices for eyeglasses and, more particularly, to trial frame systems for simulating multifocal eyeglass prescriptions.

In the course of an eye examination, it is common for a prescriptioner to demonstrate a number of different lens powers and styles to the patient . This frequently is accomplished by the use of a trial frame, such as that disclosed in Cogez U.S. Patent No. 4,448,501. Such a trial frame is capable of closely replicating the desired eyeglass prescription. However, the device disclosed in the aforementioned patent is only capable of simulating the prescription of single focus eyeglasses; it is not capable of simulating a multifocal eyeglass prescription.

Since a large number of the eyeglass-wearing public requires multifocal lens prescriptions, there is a need to provide a trial frame system which simulates a multifocal eyeglass prescription. Several attempts have been made to provide such a trial frame system, and are disclosed in Hill U.S. Patent No. 955,333; Cowan U.S. Patent No. 980,070; Griffin U.S. Patent No. 1,002,580 and Williams U.S. Patent No. 2,835,161.

Today, there are large numbers of different multifocal eyeglass styles and lens shapes, including the graduated (no line), executive, flat top, trifocal, round, curve top and above-and-below styles. Of course, each of those styles may be prescribed in a variety of magnifications and sizes to address the growing need for lenses specifically suited to an occupation or activity. Accordingly, a disadvantage common to all of the aforementioned multifocal trial frame systems is that it is not possible to mount the more modern multifocal lens designs due to the lens mounting mechanisms employed, which only allow for stacking of single vision lenses. Further, none of the systems disclosed in the

aforementioned patents are capable of accurately simulating the look and feel of a particular multifocal eyeglass prescription.

Accordingly, there is a need for a multifocal trial frame system which is sufficiently flexible to approximate a wide range of multifocal eyeglass prescriptions, and which is capable of providing the subject with a realistic look and feel of a particular multifocal eyeglass prescription.

Summary of the Invention

The present invention is a multifocal trial frame system which is sufficiently flexible to simulate a wide variety of multifocal eyeglass prescriptions with a manageable number of lens units, and is designed to provide the subject wearer with a realistic look and feel of the actual multifocal prescription. The present invention, unlike prior art devices, utilizes multifocal lens designs commonly available in the marketplace.

The trial frame system of the present invention includes a trial frame with temples having padded ends shaped to fit a variety of head sizes, and a pair of downwardly depending bosses, each of which is independently laterally adjustable relative to the frame, and a vertically adjustable nose bridge. Each of the bosses receives a lens support bracket having a pair of rims. The first rim is position adjacent to the eye of the wearer and is shaped to receive a round distance prescription lens. The second rim is positioned adjacent to the first rim opposite the eye of the wearer and is shaped to receive a multifocal lens which is larger than the distance lens.

The multifocal lens includes a neutral portion and an insert portion having a close-viewing prescription. The insert portion is incorporated into the neutral portion to form a continuous, unitary lens unit with the neutral portion. The lens support bracket holds the distance and multifocal lens units in a substantially parallel relationship so that

the lenses cooperate to simulate a specific multifocal eyeglass prescription.

In the preferred embodiment, there are a plurality of round, distance prescription lenses of varying dioptric powers. Similarly, there are a plurality of multifocal lens unit pairs, each simulating a particular multifocal lens prescription and multifocal lens style, so that when combined with the appropriate distance prescription lens, the combination is capable of simulating virtually all varieties of multifocal lens dioptric powers and styles.

Accordingly, it is an object of the present invention to provide a multifocal trial frame system which is capable of simulating a wide variety of multifocal lens prescriptions and styles with a manageable number of lens units; a multifocal trial frame system which is capable of simulating the look and feel of a wide variety of multifocal lens prescriptions; a multifocal trial frame system which utilizes a single trial frame which is sufficiently adjustable to fit comfortably a large range of head sizes; and a multifocal trial frame system which is relatively inexpensive to manufacture and adjust and is lightweight when worn.

Other objects and advantages of the present invention will be apparent from the following description, the accompanying drawings and the appended claims.

Brief Description of the Drawings Fig. 1 is a side elevation of the preferred embodiment of the multifocal trial frame system of the present invention, shown worn by a subject.

Fig. 2 is a perspective view of the trial frame system of Fig. 1;

Fig. 3 is a front elevational view of the trial frame system of Fig. 1, in which the nose bridge assembly is partially broken away;

Fig. 4 is a detail of the adjustable boss structure of the system of Fig. 1;

Fig. 4A is a sectional view taken at line 4A-4A of Fig. 4;

Fig. 5 shows a combination of distance and close viewing lenses with a flat top insert;

Fig. 6 shows the combination of Fig. 5, but with a different style flat top;

Fig. 7 shows the combination of Fig. 5, but with a trifocal insert;

Fig. 8 shows the combination of Fig. 5, but with an above-and-below insert;

Fig. 9 is a detail elevation view in section of the lens support bracket of the embodiment of Fig. 1; and

Fig. 10 is a detail of the nose bridge structure of the embodiment of Fig. 1.

Detailed Description

As shown in Figs. 1 and 2, the multifocal trial frame system of the present invention, generally designated 10, includes a trial frame 12 that supports a pair of lens brackets 14, 16, each of which supports a pair of distance prescription lens units 18, 20, and a pair of multifocal lens units 22, 24, which are of a type commonly available in the marketplace. The frame 12 includes a pair of flexible, resilient stems 26, 28, each terminating in an enlarged, resilient pad 30. The stems 26, 28 and pads 30 are sufficiently flexible so that the frame 12 is capable of fitting a wide variety of head sizes and shapes.

As shown in Figs. 2 and 3, the frame 12 includes a nose bridge assembly 32. Nose bridge assembly includes a stud 34 which is substantially rectangular in cross section and is shaped to be received within a correspondingly-shaped rectangular recess 36, set in the underside of the frame 12 at a central, thickened portion 38. As shown in Fig. 10, the stud 34 includes a recess 40 which is substantially rectangular in shape and is sized to receive a rectangular

protrusion 42 formed in the recess 36. A thumb wheel 44 includes a disk 46 which protrudes slightly above the upper surface of the thickened portion 38, and a shaft 48 terminating in a threaded portion 50. The shaft 48 extends through a hole 52 formed in the thickened portion 38, and the threaded portion 50 engages a correspondingly threaded hole 54 formed centrally in the stud 34.

The thumb wheel 46 is retained within the thickened portion 38 by snap ring 56, and tension is applied to the snap ring by a spring washer 58 which is positioned between the thumb wheel disk 46 and the floor 60 of the recess 62 which receives the thumb wheel disk. A second snap ring 64 is retained on the threaded portion 50 to prevent the stud 34 from inadvertently being removed from the threaded portion. Consequently, rotation of the disk 46 causes the threaded portion 50 to rotate relative to the stud 34, which operates to displace the stud into or out of the recess 36. The stud 34 thus is vertically adjustable relative to the trial frame 12.

As shown in Figs. 2 and 3, the stud 32 terminates in a pair of flexible, resilient arms terminating in nose pads 66 which are spaced to engage a variety of nose shapes comfortably.

As shown in Figs. 4 and 4A, the frame 12 includes a pair of downwardly depending bosses 68 (only the left boss is shown, it being understood that the structure of the right boss is identical thereto but of reverse hand) . The boss 68 includes a rectangular nut 70 having a threaded hole 72 which receives a threaded rod 74 therethrough. The rectangular nut 70 and rod 74 are located within a rectangular slot 76 formed in the frame 12.

A retainer plate 78 is attached to the underside of the frame 12 by screws 80 and includes a slot 82 through which the stud 68 extends. The plate 78 includes bosses 84, 86 which are shaped to engage the ends 88, 90 of the threaded rods 74 and form journal bearings. A knurled wheel 92 is

mounted on the threaded shaft 74 and protrudes above the upper surface of the trial frame 12 (see also Fig. 2) .

An indicator arm 94, being generally L-shaped, is attached to the stud 68 and extends rearwardly and upwardly around the frame 12 to terminate in an indicator 96. The indicator 96 is positioned adjacent to graduated markings 98 inscribed on the upper surface of the frame 12 which indicate the horizontal pupillary distance from the stud 68 (and hence lenses 18, 22) to the center of the nose bridge 32. Accordingly, by rotating thumb wheel 92, the studs 68 can be displaced laterally relative to the frame 12 to adjust the horizontal pupillary distances between the lens pairs 18, 20, 22, 24.

As shown in greater detail in Fig. 9, each of the lens brackets 14, 16 (only lens bracket 16 being shown) includes a plate 100 having an opening 102 shaped to receive the boss 68 therethrough. A pair of vertical flanges 104, 106 extend upwardly from the plate 100 and are spaced apart a distance sufficient to allow the boss 68 to be inserted therebetween. A set screw 108 is threaded into flange 104 and urges the boss 68 against flange 106 and plate 100. Accordingly, the plates 100, 104, 106 provide vertically adjustable engagement with respect to the boss 68.

An arcuate rim 110 is attached to and extends downwardly from the plate 100 and a second arcuate rim 112 extends downwardly from the plate 100 and is oriented substantially parallel to rim 110. Rim 110 is shaped to receive the circular, distance prescription lens 18 (see Figs. 2 and 3) in a releasable engagement to facilitate easy substitution of lenses 18, 20 of varying dioptric powers. The rim 112 is shaped to receive the larger, multifocal lenses 22, 24, which are permanently attached by conventional means such as nylon thread 114. As shown in Fig. 9, the boss 68 is angled with respect to the frame 12 a sufficient amount to provide a 5o pantoscopic angle between the lenses 18-24 and the vertical. Further, the trial frame is positioned on the

wearer to provide a distance of approximately 14 mm between the wearer's eye and the lenses 18, 20.

As shown in Fig. 3, the multifocal lenses 22, 24 each include a neutral portion 114, 116, and a multifocal insert portion 118, 120 having a close viewing power. In the case of lens units 22, 24 shown in Fig. 3, the multifocal style is the graduated or "no line" style. The multifocal portions 118, 120 are unitary with the neutral portions 114, 116 so that continuous lens units 22, 24 are formed.

As shown in Fig. 5, multifocal lens unit 24A includes a neutral portion 116A and a multifocal insert portion 120A, having a close-viewing prescription. The insert portion 120A is a flat top multifocal lens (also known as straight top or "D" style) .

As shown in Fig. 6, multifocal lens unit 24B includes a neutral portion 116B and an insert portion 12OB, which has a different curved top shape.

In Fig. 7, the lens unit 24C includes a neutral portion 116C and an insert portion 120C which is an occupational trifocal, flat top style. In Fig. 8, the lens unit 24D includes a neutral portion 116D and insert portions 120D which provide an above-and-below multifocal style (also known as double "D"s or double flat top style) .

The method of using the trial frame system 10 is as follows. Having obtained a prescription from a doctor which specifies the correction for distance and near-point addition, the predetermined distance prescription is selected for the patient by selecting lenses 18, 20 of appropriate power. Next, the appropriate specification for the multifocal lens unit is made. This is determined, in part, by the subjective lifestyle requirements of the patient, as well as by the patient's occupational and recreational needs. The two sets of lens units are then placed in parallel relation on the lens brackets 14, 16 and attached to the trial frame 12.

The trial frame 12 is then adjusted so that the geometric centers of the lenses 18, 20 match the pupillary distance, when the far point fixation is parallel (the patient

is looking at infinity) . The vertical orientation of the lenses 18-24 is made by adjustment of the nose bridge 32 and position of the brackets 14, 16 on bosses 68, in order to determine the optimal vertical positioning of the multifocal segments 120.

The patient is now able to perform normal tasks, such as walking, reading, using a computer and negotiating stairs, and will receive a realistic idea of the effect of the lens design under those real life circumstances. For the first time, the patient will be able to make a subjective evaluation of the lens design before purchase.

Thus, as shown in Figs. 3 and 5-8, a variety of multifocal lens styles can be created, each with a corresponding distance lens unit 20, 20A-20D of different prescriptions. In the preferred embodiment, the distance lens 20 is round and has a diameter of approximately 38 mm. The shape of multifocal lens unit 24 is preferably of the "aviator" style, having a height of approximately 42 mm and a width of approximately 54 mm. The lenses are oriented on their respective lens brackets 14, 16 (see Figs. 2 and 3), such that the geometric centers of the multifocal lenses 22, 24 are offset from the geometric centers of the distance lenses 18, 20 so that the geometric centers of the distance lens units are 4 mm inward and 1 mm upward relative to the geometric centers of their adjacent multifocal lens units.

Since the distance lens units 18, 20 are removable from their respective rims 110, it is possible to combine a given multifocal lens 22, 24 with an entire range of distance prescription lens units 18, 20. This increases the flexibility of the system and minimizes the number of separate components required to provide a wide range of prescriptions and styles.

As shown in Figs. 1 and 2, the trial frame system 10 closely approximates a conventional pair of eyeglasses in size and shape. Accordingly, it is possible for the wearer 122 (see Fig. 1) to wear the trial frame 12, walk about, read and perform normal tasks to determine the effect of the particular

multifocal style (that is, the shape of the insert portions 118, 120) on his or her ability to see a transition from distance viewing to close viewing.

In the preferred embodiment, the frame 12 is made largely of plastic, and the boss assemblies and adjustable nose bridge are made of machined aluminum. However, it is within the scope of the invention to fabricate the trial frame system 10 of any suitable, light-weight material.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention.

What is claimed is: