This invention relates to the field of treatment for dry eye syndrome, in particular, it relates to the device and method for the treatment of meibomian gland dysfunction.
Tear film is a thin, moist and protective film anterior to the cornea, and it's essential to ocular surface health and visual acuity. Chronic impairment in tear film will lead to dry eye syndrome, formally termed keratoconjunctivitis sicca. Dry eye is one of the most common reasons people visit an eye care professional. Patients with dry eye syndrome either cannot secrete enough tears or the tear quality is not good enough.
Tear film is composed of three layers anterior to the corneal epithelial cells, and its thickness is reported to be around 3 nm. The posterior mucous layer contains mucins secreted by the goblet cells mostly in the conjunctiva. The mucous layer stabilizes the tear film on the conical epithelium. The middle aqueous layer is the thickest part of the tear film, and it is secreted from the lacrimal glands. The aqueous layer is essential for spreading of the tear film, carrying nutrients and oxygen to the cornea, defending the ocular surface with immunological and antimicrobial proteins, and regulating tear osmolarity. The lipid layer is the most anterior of the tear film, and its thickness is usually in the order of 1 to 100 nm. It is secreted by the meibomian glands. The lipid layer can provide a smooth optical surface for the cornea, reduce evaporation and enhance the tear film stability.
Any chronic impairment in the each of these three layers or in the interactions among these three layers could lead to dry eye syndrome. Clinically, meibomian gland dysfunction (MGD) is the most common type of dry eye.
Meibomian glands are named after a 17th century German physician Heinrich Meibom, who gave the first detailed descriptions of these glands. They are modified sebaceous glands vertically lined up inside the tarsal plates of both upper and lower eyelids, and there are about 30-40 of meibomian glands in the upper eyelid and about 20-30 in the lower eyelids. There are numerous acini project from the main duct of each meibomian gland. Meibomian gland secretions are produced when the membranes of the innermost acini cells rupture, and lipid droplets and cell debris are released into the ducts. Meibomian glands are holocrine glands in nature, similar to other sebaceous glands. The normal lipids secretion of the meibomian glands, termed meibum, is mainly an oily mixture of wax esters and sterol esters, and some small amount of fatty acids, fatty alcohols, and sterols, etc.
MGD patients usually have impaired meibomian glands, where the openings of the glands are partially or completely obstructed by solidified and thickened lipids and/or other debris at the eye lid margins. Over time the impairment could progress to meibomian gland atrophy. The direct causes of clogging of the meibomian gland orifices are hyperkeratinization of the ductal cells and the degeneration of the acini cells. The further underlying causes include aging, hormonal changes, blepharitis, prolonged computer or cellphone use, long-term contact lens wear, etc. Normal meibum is clear, but the meibum secretion from MGD might be turbid, inspissated, and milky in color. The insufficient supply of lipids onto the ocular surface could lead to higher evaporation of the underneath aqueous layer, which could further lead to tear break up and the exposure of the underlying corneal epithelial cells. This will cause the sensation of dryness, itchiness or even burning feelings of the eye.
In the prior art, a number of methods attempting to treat or relieve the MGD have been described. The most common way is to use eye drops or artificial tears to lubricate the ocular surface. In these artificial tears, pharmaceutical expertise to balance critical parameters such as pH, surface tension, etc., are necessary to closely imitate the natural human tears. However, the instillation of artificial tears focuses on relieving the ocular dryness symptoms instead of recovering the meibomian gland functionalities, and its effective time tend to be less than one hour.
The use of steroids, androgen, cyclosporine, or lifitegrast, etc., are sometimes employed clinically to treat more severe dry eye, where artificial tears alone could not relieve the symptoms. Yet again, these medicines tend to treat the signs and symptoms, instead of recovering meibomian gland functions.
Several eyelid cleansers to clean the eyelid margins and maintain eyelid hygiene have been disclosed, including the one described in U.S. Pat. No. 8,449,928.
Warm compresses of various kinds have been developed to warm up the eyelids and soften, melt or substantially decrease the viscosity of the inspissated lipids and debris at the meibomian glands orifices. The warm compresses could be as simple as a conventional hot cloth. Sometimes, follow-up massaging with fingers after the use of warm compresses is recommended by the doctors. However, several drawbacks associated with the warm compresses include: potential contamination by unsterilized compresses; potential overheating to cause discomfort or burning; insufficient heat to melt the occlusions clogged at the meibomian glands orifices, etc.
U.S. Pat. No. 8,506,539 by Guillon et al. describes an eyelid margin wipe with temperature control in the range of 40° C. to about 55° C. for at least 5 minutes, and the heat is generated by activating one or more chemical agents. However, non-specific heating on the eyelid has a potential of adversely affecting the delicate eye region. Also, heating temperature over 50° C. poses a risk of eyelid burning or discomfort for at least some patients.
U.S. Pat. No. 6,908,195 describes a therapeutic eye and eye lid cover, which includes a pair of goggles covering the eyes, and heat a liquid reservoir to saturate the air enclosed around the eyes with water vapor to prevent evaporation from the eyes. However, this cover could only manipulate the local ocular environment, when it's worn. Once the cover is taken off, its effect for preventing evaporation is gone.
U.S. Pat. No. 9,039,718 describes a method to use an electromechanical device to move a swab cyclically around the eyelid margin to purportedly impact and remove the debris at the eyelid margin to treat ocular disorders such as dry eye syndrome, blepharitis, and meibomitis. However, the swab is effective only at the eyelid margin, and it couldn't impact other parts of the eyelid.
U.S. Pat. No. 7,122,013 describes an eyes massage device, which consists of a pair of goggles, a pneumatic-powered cylinder assembly to generate air pressure above or below the atmospheric pressure alternately to massage the eyes. However, a complicated pneumatic-powered cylinder assembly may not be very easy to use.
U.S. Pat. No. 9,675,516 describes a device for melting and expressing material from blocked glands of mammalian eyelid, which comprises a massaging bobbin that is substantially concave cylindrical in shape, and has a plurality of continuous narrow ridges extending around the massaging bobbin in a generally helical configuration, and when in use, the massaging bobbin transmits heat to the mammalian eyelid and rotates so that the massaging elements move in a direction parallel to a lash line across the mammalian eyelid. However, the movement direction is limited to be parallel to a lash line, which might limit the secretion of some meibomian glands, especially the acini and ductules that are not close to the lash line.
Another type of MGD treatment devices include an eyelid warmer that applies heat to the inner eyelids, and an eye cup that compresses the eye lid with pulses, such as described in U.S. Pat. Nos. 7,976,573, 8,187,311, 8,617,229, etc. However, elements directly contacting the ocular surface, or the inner eyelids increase system complexity and cost, and potentially may increase contamination and inflammation risks.
Also, U.S. Pat. Application 2016/0317379 describes a meibomian gland roller comprises a cylinder with a heating element to express meibomian glands. However, the cylinder may limit the area on an eyelid that can be conveniently reached in a treatment due to the physiological structure of the eye and neighboring facial structures.
U.S. Pat. No. 8,491,508 describes a device for stimulating the meibomian glands of the eyelid comprising a handle and a head, and the head comprises an eyepiece that oscillates to provide a massaging action to an eyelid. However, the fixed eyepiece limits the eyelid coverage. Similarly, U.S. Pat. No. 10,130,507 describes an eye treatment device, comprising a heating element; a thermal transfer rod; and two outer eyelid contact pieces. However, since the eyelid contact piece is fixed, the covered area is limited.
It is an object of this invention to provide a dry eye treatment device that can heat and massage the eyelids so that thickened or inspissated lipids and debris that obstruct the meibomian glands ducts and orifices can melt and be cleaned way, and the flow pathways of the secreted lipids from the meibomian glands are cleared and the expression of the lipids is ameliorated.
It is another object of this invention to provide a dry eye treatment device that could be self-administrated by the patient and simplify the treatment process of meibomian gland dysfunction. Self-administration would greatly improve the treatment convenience and increase the treatment frequency and patient compliance and may significantly reduce the financial burden of dry eye patients.
It is another object of this invention to provide a heated roller of convex cylindrical shape so that the roller could be rolled from many different directions on the eyelid to provide improved massaging of the meibomian glands with a larger area coverage and better pressing from various directions.
It is further another object of this invention to provide some embodiments of the dry eye treatment device which separate the heating element (the heat generator) from the roller (the heat applicator), so that the roller internal structure could be simplified, and its size could be significantly reduced. Further, the smaller roller could reach corners previously difficult to reach on the eyelid to cover a larger area of an eyelid during a treatment.
It is yet another object of this invention to provide an embodiment of a head-mounted dry eye treatment device, which the patient may wear comfortably in a sitting or lying position, while a heated roller or a heated plate provides heating and massaging to the eyelids.
It is yet another object of this invention to provide an embodiment of a robotic arm to directly heat and massage the eyelids with a roller, a spinning or vibrating pinhead, or a heated plate as the end effector of the robotic arm. The robotic arm and the associated computer system could be trained with machine learning with a large quantity of images and videos of real-life dry eye treatment by medical professionals, so that the device could be self-administrated by the subject, yet still could provide professional dry eye treatment.
It is still another object of this invention to provide heating and massaging of the eyelids, which may have therapeutic and cosmetic benefits, such as reducing subcutaneous adipose tissues around the lower eyelids.
The present invention relates to a dry eye treatment device, comprising: a roller, wherein the roller is connected to a holder, wherein the roller contacts and rolls over an eyelid in a plurality of directions in a treatment; a heating element to generate heat, wherein the heating element is outside the roller, wherein at least a portion of the heat is transferred from the heating element to the roller by a heat transfer element with thermal conduction; a temperature monitoring system, wherein the temperature monitoring system comprises a thermal sensor and a temperature control circuit; and an electric power source to electrically heat the heating element. The roller is of a convex cylindrical shape or a concave cylindrical shape. The thermal sensor measures a temperature of a surface of the roller, or a temperature of an element thermally connected with a surface of the roller, wherein the temperature control circuit ensures the temperature of the surface of the roller is within a predetermined temperature range, wherein the predetermined temperature range is a temperature range within 40 to 60° C. The roller could comprise a thermally conductive coating layer, and the coating layer could be conformable. The roller could be motorized, wherein the speed of rotation of the roller is adjustable. The device further comprising a thermally conductive gel to be applied between the roller and the eyelid in the treatment. In some embodiments, the dry eye treatment device is a head-worn device, wherein the head-worn device comprises a case and a strap to fixate on a head of a subject, wherein the roller is motorized and heated, and the roller and holder are located inside an eye chamber of the head-worn device. In some other embodiments, the roller and the holder are connected to a robotic arm, wherein the roller is an end effector of the robotic arm, wherein a computer controls the motion of the robotic arm. The end effector of the robotic arm is replaced with a member selected from the group consisting of a spinning pinhead, a vibrating pinhead, a heating plate and an intense pulsed light source. The robotic arm and the computer are trained with machine learning.
The present invention also relates to a dry eye treatment device, comprising: a roller, wherein the roller is connected to a holder, wherein the roller contacts and rolls over an eyelid in a plurality of directions in a treatment; a heating element to generate heat, wherein the heating element is inside the roller, wherein at least a portion of the heat is transferred from the heating element to the roller; a temperature monitoring system, wherein the temperature monitoring system is outside the roller, wherein the temperature monitoring system comprises a thermal sensor and a temperature control circuit; and an electric power source to electrically heat the heating element. The heating element is a resistance heating element or a heat lamp inside the roller, or it could be a roller surface of the roller heated by eddy currents of induction heating.
The invention further includes a method for dry eye treatment, comprising: cleaning an eyelid with a first cleansing wipe; heating a roller to a predetermined temperature; applying thermally conductive gel between the roller and the eyelid; rolling the roller over an eyelid in a plurality of directions; and removing the thermally conductive gel and expressed debris with a second cleansing wipe. The roller is of a convex cylindrical shape or a concave cylindrical shape. Further, the dry eye treatment method comprises increasing the predetermined temperature by an increment, and repeating the method for dry eye treatment.
This convex cylindrical shape in
Compared with a cylindrically shaped roller, the advantage of a concave or convex cylindrically shaped roller is the flexibility to adapt to the shape of an eye, and reach a larger eyelid area in treatment, since the physiological structures of the nose, the frontal bone and the zygomatic bone form relatively complex contours that may obstruct the use of a cylindrically shaped roller, but may be reached with a concave or convex cylindrically shaped roller of an appropriately chosen size. Preferably, the roller is made of metal. In some embodiments, a thin thermally conductive coating layer could be added to the roller surface. If added, the coating layer is the interface contacting the skin, hence the coating layer material should have dermatologically proven skin compatibility. Preferably, the coating layer could be made of conformable elastomeric materials or materials easy to clean and sterilize for repeated use, including but not limited to silicone rubber, methacrylate polymers, fluoroelastomer, or polytetrafluoroethylene. A conformable coating layer may enhance the contour match between the roller surface and the eyelid and improve the heat transfer. In some embodiments, this coating layer could be porous. Since the roller 14 or 20 is used to contact the eyelid to warm and melt inspissated lipids, preferably, the total length of the roller 14 or 20 between the two end surfaces is about 2 mm to 20 mm Along the shaft direction, the roller diameter varies. Preferably, taking the maximum and minimum roller cross-section diameter into account, the diameter of the roller is within the range of 1 mm to 20 mm, so that the roller could directly heat all or at least a majority part of the eyelids.
As shown in
The roller could have a smooth surface formed by bare metal or a metal substrate with a coating layer, or it could have ribs or ridges protruding from the roller surface, and preferably they form a repeated geometrical pattern. The protrusions on the roller surface could be formed directly by the metal or it could be formed by the coating layer materials. When a heated roller is applied to an eyelid, the protrusions on the roller surface will press into the eyelid surface in action, increase the contact area with the eyelid skin, and provide enhanced massaging to facilitate the expression of the meibum and the clearance of the of inspissated or solidified lipids and debris at the ducts and orifices of the meibomian glands. Additionally, the massaging effect by the protrusions on the roller surface could help cutaneous microcirculation.
A temperature monitoring system could be used to monitor and control the heating process in real time. The temperature monitoring system comprises a thermal sensor 28 and a temperature control circuit (not shown). The thermal sensor 28 is in contact with a roller end surface or it is in close proximity to the roller end surface, with a distance preferably smaller than 1 mm. The thermal sensor 28 is connected to the electric power source and the rest of the temperature monitoring system via a wiring structure 29. The thermal sensor could be a thermal couple or a thermistor, and it monitors the real-time temperature of the roller surface. The temperature control circuit compares the real-time temperature of the roller surface with a predetermined temperature range and adjusts the electric current of the heating element, in order to maintain the roller surface temperature within a predetermined temperature range, which is usually within 40 to 60° C., such as 40 to 45° C. If the thermal sensor 28 is not in direct contact with the roller end surface but it is in close proximity to the roller end surface, a calibrated temperature of the roller surface based on the sensor real-time temperature measurement could be used. More preferably, the operator of the device could adjust the desired temperature range, so that it's customized to the need of a specific subject with guidance from a medical professional. In
Further, in some other embodiments, a thin silicone rubber heating sheet is applied to the roller surface, and the heating element is not inside the roller, but directly on the roller surface.
Furthermore, in some other embodiments, an induction heating unit embedded inside the holder could be used to generate eddy currents in the roller surface. Preferably, in these embodiments, a thermally conductive and electrically insulating coating layer is added to insulate the eyelid skin from the eddy currents. In these embodiments, the heating element is the roller surface heated by eddy currents of induction heating.
This invention further provides a dry eye treatment device, where the heat generator (i.e., the heating element) and the heat applicator (i.e., the roller) are separated, and the heating element is outside the roller. Between the heating element and the roller, a heat transfer element with high thermal conductivity is used to transfer heat. One of the main advantages of the separation of the heat generator from the heat applicator is that the heat applicator, i.e., the roller, could be made much smaller since no complicated internal structure is necessary. With a reduced size, the heated roller could be employed more flexibly so that the small roller could reach corners previously difficult to reach on the eyelid to cover a large area of an eyelid under treatment. Further, usually the heat generator requires an electric current, and if part of the heat transfer element is thermally conductive and electrically insulating, no electric current is involved in the roller part. This could help the operator avoid electric shocks, which will increase the safety of use with the instrument.
In
Note that in
In the above embodiments, plain bearing with thermally conductive lubricant is used at the journal and the roller. However, thermally conductive ball bearings could also be employed to enable rolling and efficient heat transfer to the roller.
Further, in the above embodiments, the roller is manually rolled on closed eyelids to provide both heating and massaging for dry eye treatment. However, a motorized roller could be employed in some embodiments, so that the roller automatically rotates.
A motor 70 is connected with a wiring structure 71 to supply electric power. Preferably, there is a button (not shown) in the handle to activate the motor by an operator. The motor shaft 72 is rotated when the motor 70 is activated, and gears 73, 74, 75, and 76 form a gear group to transmit torque so that the shaft 77 of the roller 20 is driven to rotate. Preferably, the speed of rotation of the roller is adjustable by the user. In the embodiment shown in
Further, other than being operated by an eye care professional, the disclosed device and method of dry eye treatment could be used for self-administration. If a subject were to use the disclosed device by oneself, preferably a subject will look into a mirror or a camera with real-time display in a treatment, and the eye under treatment should be closed, while the other eye could open when necessary to ensure desired position and movement of the roller.
Preferably, a thermally conductive gel is applied to the roller surface or applied to the eyelid by an automatic dispenser (not shown) embedded in the head-worn device before the roller starts to contact the eyelid. In some other embodiments, the thermally conductive gel could be applied onto the closed eyelids by the operator manually.
In some other embodiments, the head-worn device roller movement could be in a plurality of directions, including but not limited to the direction along the eyelid margin and the direction perpendicular to the eyelid margin. The variation of the direction where the heated roller is applied to the eyelids may help fully express the inspissated or solidified meibum in the ducts and orifices of meibomian glands.
The end effector of the robotic arm could also be an intense pulsed light source for intense pulsed light treatment. Further, the end effector could be a laser, and the laser beam could scan across the eyelid and adjacent tissues during a treatment. When a light source is used at the end effector of the robotic arm, it's preferred to use an eye mask to cover at least a portion of an eye, including the entire cornea, such that no light could enter into the eye during the treatment.
Preferably, the subject is lying comfortably on a flat or an inclined bed before the robotic arm is used. The robotic arm is connected to the electric power and a computer (not shown) is used to control its motion based on the feedback from the visible camera (or cameras) 113 and the thermal camera 114, and the motion and pressure sensors (not shown in
Preferably, the robotic arm treats both eyes sequentially for a cycle, and optionally the cycles could be repeated in a number of times. For example, the robotic arm could treat the left eye for 10-15 minutes and then the right eye for another 10-15 minutes. Alternatively, the robotic arm could heat and massage the left eye of a subject for 5 minutes and the right eye of the subject for another 5 minutes and repeat the cycle two or three times.
More preferably, the robotic arm and the associated computer system are trained with machine learning (i.e., robot learning) with a large quantity of images and videos of real-life dry eye treatment by human medical professionals, so that the device could be self-administrated by the subject, yet still could provide professional dry eye treatment, comparable to that in a hospital or an ophthalmic clinic. The machine learning algorithm could be included in the computer software for the robotic arm motion control. Further, with artificial intelligence employed in the robotic arm, human errors could be minimized in the treatment of an eye.
Before a treatment operation with any embodiment of the disclosed device, it's preferred to clean the closed eyelids with a first cleansing wipe, and the first cleansing wipe could contain cleansing chemicals compatible with the eyelid margin, including the skin and the conjunctiva. This first cleansing wipe is used to reduce preexisting debris on the eyelid, especially near the eyelid margin. Alternatively, a cleansing tissue or cloth, a sterilized wipe or other appropriate means could also be used for eyelid cleaning. A roller of a convex cylindrical or concave cylindrical shape is heated to a predetermined temperature or a temperature range before use. Preferably, the warm-up time of the roller is in the order of several seconds to several minutes. Apply thermally conductive gel to the heated roller or spread the thermally conductive gel on the eyelids, so that the thermally conductive gel can fill the space in the contact area of the roller and the eyelid skin, to ensure an effective heat transfer from the heated roller to the tissues in the eyelids. It's preferred to roll the heated roller over an eyelid in a plurality of directions, including but not limited to the direction along the eyelid margin and the direction perpendicular to the eyelid margin. The variation of the direction where the heated roller is applied to the eyelids may help fully express the inspissated or solidified meibum in the ducts and orifices of meibomian glands.
After the heated roller treatment, the thermally conductive gel and the expressed debris could be removed by cleaning with a second cleansing wipe. Alternatively, a cleansing tissue or cloth, a sterilized wipe or other appropriate cleaning means could also be used after the dry eye treatment.
Depending on the underlying etiology and severity of dry eye, the melting point of the meibum could be significantly different for different subjects. In a preferred method, the roller is first heated to a predetermined temperature range of about 40° C. If after the heated roller massaging treatment, the meibomian gland expression is still not significantly improved, the predetermined temperature of the roller surface could be increased by an increment and the disclosed dry eye treatment method could be repeated, as long as the increased temperature is still safe and tolerable for the subject. A typical temperature increment could be 0.5° C., 1° C. or 2° C. The upper limit of the roller surface temperature should be less than 60° C. to avoid eyelid burning or discomfort. For most subjects, extra care has to be taken when the roller surface temperature is above 45° C. to minimize discomfort. Therefore, a small increment (for example, less than 2° C.) in temperature increase is preferred when the roller surface temperature is above 45° C. and may need approval from medical professionals.
In the described embodiments above, when the eyelids are closed, the palpebral conjunctiva is in direct contact with the cornea. However, in some embodiments, a contact lens may be employed, which is thermally insulating, to isolate the effect of the heating to the eyelids and reduce its impact to other parts of the eye, such as the cornea. In other embodiments, a scleral lens with a large-diameter (larger than regular contact lenses) to vault over the entire corneal surface and rest on the sclera (the white of the eye), could be used to protect the cornea and limit the heating and massaging to the eyelids. The tear fluid in the space between the cornea and the back surface of a scleral lens may provide comfort during the dry eye treatment. This may be particularly important for patients with keratoconus and other corneal irregularities.
All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety in the present application.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
Priority is claimed to Provisional U.S. Patent Application Ser. No. 63/066,312 by A Zhang filed Aug. 16, 2020 and entitled “DEVICE AND METHOD OF DRY EYE TREATMENT”, the disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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63066312 | Aug 2020 | US |