Apparatus for custom tinting soft contact lenses by dispenser of lenses

Presented is a method and apparatus for custom tinting soft contact lenses in the dispensing office prior to dispensing such lenses to the wearer, or even after they have been dispensed and worn for a time. In the past, contact lenses have been tinted by mass production means by a very limited number of manufacturers. In one aspect, this invention presents a device that can be used by a dispensing optician, optometrist or ophthalmologist to custom tint soft contact lenses to the specification of the wearer while the wearer waits for the lenses to be tinted. In terms of structure, the apparatus comprises a hand-held device into which a soft contact lens may be deposited and sealed and subjected to the chemical reaction of an appropriate dye to tint the contact lens to the requisite color. The lens is held contained within the device for a requisite time to secure adequate reaction of the dye stuff with the material from which the lens is manufactured, and subsequently the dye is flushed from the apparatus and the lens removed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention. 
This invention relates to soft contact lenses, and particularly to a method 
and apparatus for tinting such soft contact lenses within the dispensing 
office, or in soft contact lens manufacturing facilities. 
2. Description of the Prior Art 
The search of the prior art has revealed the existence of the following 
U.S. patents which are believed to be the most pertinent related to the 
subject matter of this application Ser. Nos: 2,241,415; 3,034,403; 
3,171,869; 3,557,261; 3,679,504; 3,992,563; 4,157,892; 4,252,421; 
4,349,470; 4,4,6,814; 4,447,474; 4,460,523; 4,468,229; 4,472,327; 
4,494,954; 4,518,390. 
Out of this group of patents, only U.S. Pat. Nos. 2,241,415; 3,557,261; 
4,447,474; 4,460,523; 4,472,327 and 4,518,390 appear to show any type of 
structure for tinting existing contact lenses, and it does not appear from 
these patents that the structures illustrated in these patents in any way 
conflict with the method and apparatus disclosed and claimed herein by 
applicant. The remaining patents mentioned above relate to various methods 
and processes, some of which may produce the same end result produced by 
applicant through the practice of his invention disclosed herein, but 
which differ substantially from applicant's method and apparatus. 
Applicant has been an optometrist for a number of years and has been in 
communication with many other optometrists, dispensing Opticians and 
Ophthalmologists and various optical equipment manufacturers and has 
observed that in the great majority of cases almost all dispensing 
Opticians, Optometrists and Ophthalmologists order tinted soft contact 
lenses from only a very limited number of manufacturers and distributors. 
A brief synopsis of the industry will promote an understanding of the 
problem solved by the subject invention. 
Soft contact lenses are prescribed and fitted by three types of eye care 
practitioners: Ophthalmologists, Optometrists, and, to a limited extent, 
Opticians. It has been reported that there are about 12,500 
Ophthalmolgists in the United States, with 11,000 of these involved in 
regular patient care as hospital or office-based physicians. It has been 
estimated that half or more of these eleven thousand Ophthalmologists 
offer dispensing services in addition to prescribing corrective eyewear, 
sometimes in conjunction with Opticians. It has been estimated these 
11,000 Ophthalmologists account for 30% of the total retail corrective 
lens market and about 20% of the contact lens market, operating from six 
thousand locations with revenues of 1.35 billion dollars. It is 
interesting to note that of all dispensing Ophthalmologists, as of 1984 
more fit soft lenses (73%) than hard lenses (71%) or gas permeable lenses 
(51%). It is also interesting to note that with respect to 
Ophthalmologists' contact lens practices, the cost of being fitted with 
contact lenses by an Ophthalmologist has decreased significantly in recent 
years. For example, in late 1978, the average cost of soft contact lenses 
from this source was $308.00; in 1979, it had fallen to $292.00, and by 
the end of 1982, to $262.00. It has been observed that in general, the 
prices paid to Ophthalmologists for contact lenses are, on average, higher 
than those paid to Optometrists or Opticians. 
With respect to Optometrists, in December of 1984 it was reported that 
there are approximately 22,000 practicing Optometrists in the United 
States. Of these, 80% (about 17,600) work independently. The other 20% 
include Optometrists working for chain optical houses and about 2,000 who 
work for Government, health maintenance organizations or Ophthalmologists. 
It has been reported that of the contact lenses fitted by Optometrists, 69% 
are soft contact lenses and only 17% are hard contact lenses. Doctors of 
Optometry average twelve pairs of new contact lens fittings per month 
(compared to ten for Ophthalmologists), and their fees generally lie 
between those of Ophthalmologists and Opticians. The cost of being fitted 
for contact lenses by Optometrists is reported to be falling, following 
the general industry trend. In late 1978, for example, it was reported 
that new soft lenses cost $285.00, but by 1979, the cost was down to 
$258.00 and by 1982, the cost had been reduced to $218.00. 
With respect to dispensing Opticians, it has been reported that only 22 
states license Opticians. The Opticians Association of America estimates 
that there are about 26,000 dispensing Opticians in the United States. 
There apparently has been a higher growth rate among Opticians than among 
Ophthalmologists or Optometrists, reflecting their increasing roles as 
primary fitters and as adjuncts to the other two classes of practitioners. 
It has been reported that 55% of independent dispensing Opticians fit soft 
contact lenses while 52% fit the hard contact lens. Additionally, it has 
been reported that 80% of all contact lenses fitted by independent 
dispensing Opticians are of the soft contact lens type and only 13% are of 
the hard contact lens type. With respect to cost, prices paid for lenses 
acquired from Optician outlets tend to be the lowest in the industry, with 
the large chains charging somewhat less than the independents and small 
chains. For 1981, for instance, the first year for which separate data are 
available, independent and small chain Opticianries charged, on average, 
$178.00 for soft lenses; in 1982, their average price was $160.00. 
It appears however that the contact lens distribution mechanism is changing 
very rapidly because of the entry into the contact lens business of 
optical and drug chains. Data on optical and drug chains and the number of 
the contact lenses fitted from this source are particularly difficult to 
come by, and when available, are obscure or commingled with data for 
independent and small chain outlets. However, the data that are known 
indicate that large chains now provide as much as 40% of all contact lens 
fittings. Obviously, this large share of the market is both a cause and a 
result of the downward price trends observed for all contact lens fitters. 
Chain outlets offer lenses at lower prices than other sources ($100.00 per 
pair of soft contact lenses in 1982) and thus exert a downward pressure on 
the entire price structure of contact lenses, including soft contact 
lenses. 
As late as 1978, 43 states placed restraints on price advertisements by eye 
care dispensers. In that year, however, the U.S. Federal Trade Commission 
overruled these laws and thus paved the way for the great growth of chain 
outlets, price rivalry, and price reductions. Since low price appears to 
be a key strategy of chain outlets, the FTC ruling strongly enhanced their 
market position. Indeed, observation makes it apparent that large chains 
are growing larger through expansion and merger, and the establishment of 
manufacturers' outlets, even to the extent of offering franchises to 
Optometrists and Opticians. It is obvious that the large optical chain has 
become an important part of the contact lens distribution mechanism and 
promises to play a larger role in future years. For instance, in 1982, it 
was reported that eight of the largest chains control approximately 2,164 
outlets for contact lenses, with only three of these large chains 
controlling approximately 1,765 outlets. 
The marketing of contact lenses, both hard and soft, to dispensers is 
effected through distribution by manufacturers of their contact lenses to 
the three groups of dispensers, who in turn make them available to 
patients. Thus, manufacturers' promotional efforts are mainly directed to 
these professionals. It is at this point that the tinted soft contact lens 
enters the picture. The large inventories of contact lenses required by 
the manufacturers to be maintained in-house by the professionals may or 
may not include tinted soft contact lenses. The problem involves a number 
of factors including cost, availability of suitable colors, the time frame 
within which suitably tinted soft contact lenses may be supplied by a 
manufacturer, and the ultimate opinion of the purchaser as to the cosmetic 
effect of the tinted soft contact lenses. 
Accordingly, it is one of the objects of the present invention to make it 
possible for each of the dispensers, whether he be an ophthalmologist, an 
optometrist, or a dispensing optician, to custom tint an existing "raw", 
i.e., clear, contact lens in his own shop or laboratory or office, often 
while the patient or purchaser waits for the lens to be tinted the same 
day it is ordered. 
Another object of the invention is the provision of a kit which includes 
the dyes necessary to effect tinting of the "raw" or clear lenses, the 
apparatus to be used by the dispenser in effecting the tinting by the 
application of dye to the soft contact lens, the apparatus being 
susceptible of manipulation by hand to tint single soft contact lenses or 
pairs thereof. 
Still another object of the invention is the provision of apparatus adapted 
to be kept in the optician's, optometrist's, ophthalmologist's or soft 
lens manufacturer's facility, shop or office, and which is readily 
available for use by the dispenser to effect tinting of soft contact 
lenses on an indiviudual basis so as to customize the intensity of the 
tinting operation to the suitability of the purchaser. 
Another object of the invention is the provision of a method of operation 
of such apparatus to effect the tinting of soft contact lenses. 
The invention possesses other objects and features of advantage, some of 
which, with the foregoing, will be apparent from the following description 
and the drawings. It is to be understood however that the invention is not 
limited to the embodiment illustrated and described, since it may be 
embodied in various forms within the scope of the appended claims. 
SUMMARY 0F THE INVENTION 
In terms of broad inclusion, the apparatus and method of the invention 
includes the provision of a relatively small and hand-held apparatus which 
permits the admission of an existing soft contact lens into the apparatus, 
in such a manner that portions of the enclosed contact lens to be tinted 
are exposed within the appaatus while the enclosed contact lens is sealed 
in such a way within the apparatus that areas of the contact lens not 
intended to be tinted are sealed from those areas that are intended to be 
tinted. The apparatus provides means for the admission of an appropriate 
dye into the apparatus so that such dye comes into intimate contact with 
those areas of the contact lens intended to be tinted. After injection of 
the dye into the apparatus and contact of the dye with the specific lens 
area to be tinted, the apparatus may be set aside for a prescribed time, 
about 15 to 30 minutes, to permit a reaction to take place between the dye 
and the lens material, the length of time that the dye is permitted to 
remain in contact with the lens material in large measure determining the 
intensity of the tint of the lens. After the prescribed time, the dye 
material is flushed from the apparatus and the lens is rinsed with a 
saline solution while maintained within the apparatus, the rinse solution 
coming into contact with those areas of the lens that have previously been 
subjected to the dye. The purpose of the rinse is to remove all traces of 
the dye from the lens and the apparatus prior to release of the lens from 
the cavity within which it is sealed. Thereafter, the tinted lens is 
removed from the apparatus and subjected to immersion in a buffer solution 
for a prescribed time to insure that no trace of the dye remains on the 
surface of the contact lens, and to return the lens to the proper pH 
value. Thereafter, the lens is removed from the buffering solution, rinsed 
with saline and placed in a sterile saline solution until dispensed to the 
patient.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In terms of greater detail, the soft contact lens tinting apparatus of the 
invention is illustrated in its assembled forms in FIGS. 1 and 2, and 
designated generally by the numeral 2. As there illustrated, the apparatus 
comprises a tubular housing member designated generally by the numeral 3, 
and fabricated preferably from a synthetic resin such as polypropylene, or 
a metal such as stainless steel, or other suitable material that is 
dimensionally stable and not subject to corrosion or deterioration. The 
tubular housing 3 is open at its upper end 4 and is provided with a 
radially inwardly extending bead 6 spaced from the open end 4 for a 
purpose which will hereinafter be described. Except for the inwardly 
extending bead 6, the interior surface 7 of the tubular housing 3 is of 
uniform diameter to adjacent the opposite end portion 8 of the tubular 
housing, where the inner periphery of the tubular housing is provided with 
an outwardly tapering surface 9 as shown. 
Fitted into the upper end of the tubular housing 3 is a sealing die 
designated generally by the numeral 12 and retained in position within the 
interior of the tubular housing by the circular bead 6 which projects into 
a complementarily configured annular groove 13 formed around the outer 
periphery 14 of the sealing die. The construction of the sealing die is 
illustrated in detail in FIGS. 8 and 9, shown apart from the rest of the 
structure, and in FIG. 2 illustrating the cylindrical configuration of the 
outer periphery of the sealing die which is dimensioned to fit snugly into 
the tubular housing if the sealing die is adapted to be removably secured 
within the tubular housing, or, as preferred, intimately contacting the 
inner peripheral surface 7 of the tubular member 3 if the sealing die is 
cast in place in the upper end of the tubular housing as illustrated in 
FIG. 2. As illustrated in FIG. 8, the sealing die is provided with a 
counterbore 16 which bottoms out at a level 17 and which at its end 
adjacent the surface 17 is annular in configuration to form a projecting 
stud or post 18 centrally disposed within the sealing die 12, and provided 
with a concave surface 19. To provide some idea of the size of the sealing 
die, it is noted that in an actual model, the overall diameter of the 
ealing die, which corresponds very closely to the inner diameter of the 
tubular housing 3, is only 18.2 millimeters, while the diameter of the 
cylindrical post 18 may range from 4 to 4.5 millimeters. This diameter, it 
will be recognized, roughly coincides with the diameter of the iris in the 
human eye. 
At its lower end 21, it will be seen that the wall 22 is provided with an 
interior periphery 23, and that in the area 24 the interior periphery of 
the sealing die is chamfered or formed as illustrated, the chamfered 
surface 24 being semi-spherical in configuration. An extension of the 
spherical surface 24 into the region of the concavity 19 on the post 18 
would coincide to the curvature of the concavity 19, so that the curved 
concave surface 19 is in effect an isolated or spaced extension of the 
curved surface 24. Again merely to illustrate the close tolerances that 
are designed into the apparatus, the diameter of the counterbore 16 may 
conveniently be set to between 11.5 millimeters and 12 millimeters, while 
the base diameter of the chamfered area 24 is 13.5 millimeters. Referring 
again to FIG. 8, it will be seen that there are two radially spaced bores 
26 projecting axially parallel to the longitudinal axis of the sealing die 
and extending through the bottom surface 17 of the counterbore 16 so that 
each of the bores 26 communicates with the annular chamber forming the 
bottom portion of the counterbore 16 surrounding the centrally disposed 
post 18. 
I have found that this sealing die may be conveniently molded from silicone 
or any other soft, pliable material that is non-toxic or non-contaminating 
to the lens material. As indicated previously, the sealing die may be 
related to the surrounding tubular housing 3 in a detachable manner, or, 
as illustrated in FIG. 2, the sealing die may be molded in situ. 
Referring to FIGS. 2 and 5, it will be seen that the lower end of the 
tubular housing 3 is provided on diametrically opposite sides of the tube 
with slots 27 that extend axially along the tube for a predetermined 
distance and lead into a transverse locking recess 28 as shown. The two 
diametrically opposite slots 27-28 are adapted to receive in detachable 
engagement, the radially outwardly projecting lock lugs 29 that lie 
fixedly embedded in the base member designated generally by the numeral 
31, which is formed from an appropriate metal or plastic material to 
provide a tubular extension 32 having an outer periphery 33 the diameter 
of which is gauged to form a snug slip fit with the interior circumference 
7 of the tubular housing 3. Around one end, the base member 31 is provided 
with a collar 34 adapted to provide a shoulder 36 on which is supported an 
annular and resilient seal ring 37 against which the lower edge 38 of the 
tubular housing 3 may abut when the lock lugs 29 are detachably caught in 
the slots 27-28. Preferably, the seal ring 37 is fabricated from a 
resilient material so that when the tubular housing 3 is pressed 
downwardly against the seal ring 37 and rotated slightly to engage the 
projecting lugs 29 in the recesses 28, there will remain a slight upward 
bias on the tubular housing 3 provided by the natural or inherent 
resilience of the seal ring 37. This will insure that during manipulation 
of the apparatus the union between the tubular housing 3 and the base 
member 31 will not be inadvertently broken, while permitting the tubular 
housing to be removed from the base member 31 at will. 
Extending axially through the base member 31 is a central bore 41 that 
extends through the entire length of the base member 31. In an actual 
model of the apparatus, the bore is approximately 4.9 millimeters in 
diameter, and snugly receives in a sliding slip fit the stem 42 of the 
plunger designated generally by the numeral 43 and illustrated in FIGS. 6 
and 7. The plunger is provided at one end with a cylindrical head 44 the 
bottom surface 46 of which is integral with the stem 42 and perpendicular 
to the longitudinal axis thereof. The cylindrical surface 47 is gauged to 
make a snug slip fit with the interior surface 7 of the tubular housing 3, 
the fit being preferably gauged so that there is no perceptible transverse 
movement of the plunger head 44 in the bore of the tubular housing 3, but 
with sufficient tolerance between the two surfaces to permit the sliding 
advancement of the cylindrical head 44 within the tube. 
The top surface 48 of the cylindrical head 44 is parallel to the bottom 
surface 46 and of course perpendicular to the longitudinal axis 49 of the 
plunger. Formed on the top surface 48 of the cylindrical head 44 is a 
semi-spherical dome 51 having a curved or arcuate surface 52 which may be 
spherical but which need not be spherical. Regardless of the curvature of 
the curved surface 52, it should be understood that the curvature of this 
surface is complementarily to the curvature of the curved chamfer 24 as 
illustrated in FIG. 8, so that when a soft contact lens body 53 (FIG. 2) 
is draped over the dome 51 as illustrated in FIG. 2, an annular band next 
adjacent the outer periphery of the contact lens lies sealed between the 
annular curved surface 24 and the complementarily curved surface 52 of the 
plunger while a central portion of the soft contact lens lies sealed 
between the concave surface 19 of the central post 18 and the central 
portion of the curved surface 52 as illustrated. 
With the soft contact lens thus disposed between the sealing die and the 
plunger, the parts are retained in this relationship by a coiled 
compression spring 54 disposed between the top surface of the base member 
31 and the surface 46 of the plunger to resiliently bias the plunger in an 
upward direction as illustrated in FIG. 2. The tension of the coil 
compression spring is gauged to maintain a resilient force on the plunger 
and maintain the seal between the top surfaces of the contact lens 53 and 
the associated contiguous surfaces of the sealing die 12. 
It will of course be understood that the soft contact lens 53 is placed on 
the dome 51 with the tubular housing 3 removed from the base structure 31. 
After placement of the soft contact lens on the dome 51, the tubular 
housing is dropped over the assembly of base member and plunger and the 
laterally projecting lugs 29 are locked in the slots 28. At this point, an 
appropriate dye is injected into the apparatus through the aperture 26 
(FIG. 8) so that the annular area of the soft contact lens that lies 
surrounding the central post 18 on the one hand and the inner periphery 23 
of the sealing die on the other hand, is exposed to the dye, which is 
injected in a sufficient quantity, as illustrated at 26 in FIG. 1, to 
provide a reservoir of such dye that lies trapped in the annular chamber 
at the face of the counterbore 16. Thus, an annular surface of the soft 
contact lens is in intimate contact with the pool of liquid dye, this 
relationship being maintained for a sufficient time, say 15 to 30 minutes, 
depending upon dye concentration and temperature, to secure the intensity 
of tinting of the soft contact lens that is desired by the patient. I have 
found that, depending upon the materials used for the contact lens, and 
the type of dye injected into the apparatus, the time of intimate contact 
between the contact lens and the dye may range from ten minutes to two 
hours. I have also found that the time element is reduced if the plunger 
43 is heated to about 150.degree. F. prior to insertion into the tubular 
housing. Preferably, the entire apparatus is heated to approximately 
150.degree. F., so that thermal equalization of all of the parts of the 
assembly occurs prior to insertion of the soft contact lens, so that heat 
from the associated parts in contact with the contact lens is conducted 
into the contact lens material itself. Additionally, I have found that the 
reaction between the contact lens material and the dye is enhanced if the 
dye itself is heated to approximately 150.degree. F. 
Heating the parts to approximately 150.degree. F. does not render them too 
hot to touch with the bare hands, and assures a rather rapid reaction 
between the dye and the exposed portion of the contact lens. I have found 
further that it is only the exposed portion of the contact lens that is 
tinted, i.e., the dye material does not migrate laterally through the 
contact lens material so as to form an indefinite inner and outer 
periphery. Rather, the line of demarcation between the untreated lens 
material and the treated or dyed lens material is sharp and clear and 
defined by the limits imposed by the apparatus. 
After the requisite time has passed for the reaction to have completed the 
dying of the lens to the intensity desired, the surplus dye is aspirate 
from the apparatus by an appropriate suction device forming no part of 
this invention. Alternatively, the entire apparatus may be inverted, at 
which time the dye will run out of the reservoir in which it is contained 
in the apparatus and be disposed of in any convenient manner. 
No attempt is made to salvage this excess dye product. Following removal of 
the excess dye, the entire apparatus may be held under a stream of 
appropriate rinsing solution which may be saline solution, or another 
appropriate solution which floods the chamber in which the dye was 
previously contained and rinses therefrom all vestiges of the dye. 
Following such rinsing, which may proceed for a specific time, the tubular 
housing is removed from the base member, thus giving access to the now 
tinted soft contact lens which remains loosely adherent on the domed 
surface 52. The lens is removed from the domed surface, and immersed in an 
appropriate buffer solution for approximately 1 to 3 hours. Such buffer 
solution may be any of a number of such solutions that are well known in 
the art. Following buffering of the tinted lens for the specified time, 
the lens is removed from the buffering solution, rinsed in an appropriate 
rinsing solution, which again may be sterile saline solution, and the now 
rinsed yet tinted soft contact lens is place in a sterile saline solution 
for storage until dispensed to the patient. 
From the above it will be seen that the structure or apparatus, which may 
be used by a professional optician, optometrist or ophthalmologist to tint 
in his own office or laboratory "raw" contact lenses manufactured by 
others, is a simple apparatus, simple to use and effective in securing the 
degree of tinting of a soft contact lens that is appropriate for a 
particular patient. It will also be noted that while I have described only 
one such apparatus, most soft contact lenses that are tinted are tinted in 
pairs and the dispenser using this apparatus and method should of course 
be equipped with two such apparatuses so that a pair of soft contact 
lenses may be tinted at the same time so as to secure the same degree of 
color intensity in each of the lenses. 
Having thus described the invention, what is believed to be new and novel 
and sought to be protected by Letters Patent of the United States is as 
follows.