DESC:TECHNICAL FIELD

The present disclosure generally relates to the field of medical devices. Particularly, but not exclusively, the present disclosure relates to a wearable device and a system to determine corrective refractive parameters of a subject.

BACKGROUND

Subjective refraction is an iterative process of testing a subject for determining their refractive error by incorporating their feedback. In the current methods of subjective refraction, eye care professionals assess a subject’s vision by manually placing multiple lenses in front of the subject’s eyes to arrive at a refractive error prescription.

Existing technologies perform subjective refraction tests involve setting a visual chart such as a Snellen chart and the like, as a target. During the subjective refraction test, the operator seeks feedback from the subject to determine lens-settings that provide better acuity to the subject. Further, the subjective refraction tests may be performed using trial frame and trial lens kit. The trial frame is a metal eyeglass that the subject wears. The trial frame contains slots for an optometrist to manually place different trial spherical and cylindrical lenses. However, placing one or more fixed power lenses stacked in front of eyes of the subject tends to make the system bulky, complex and susceptible to damage. Further, risk of repetitive stress injuries may occur to the optometrist due to the laborious nature of interchanging lens.

Another existing technique utilizes a manual refractor. The manual refractor combines the trial frame and trial lens kit into one large heavy container. The large heavy container is attached to an ophthalmic chair unit and hung in front of the subject’s face. The optometrist uses one or more dials present on the manual refractor to change the spherical and cylindrical lenses. However, due to the complexity and size, the manual refractor is unfriendly to subjects as well as the optometrists. Also, usage of the manual refractor is restricted only to the clinical environment as it is heavy. Generally, procedure of operating manual refractor is complex, and hence, requires trained optometrists for its operation.

Furthermore, the existing techniques include a digital refractor that replaces the mechanical usage of dials using motors that are controlled from an operating console. By selecting the powers on the console, the digital refractor automatically moves the correct lenses into place. This technique reduces the risk of repetitive stress injury but the commercially available digital refractor is very expensive. Further, the motorized movement of the lenses is prone to wear and tear that may add on to the cost of the digital refractor. Also, the digital refractors have low mobility.

Therefore, the existing techniques are specifically used within the clinical environment due to factors such as heaviness, space consumed and non-portability. They are not subject-friendly and require a trained optometrist for operating the refractors. Therefore, problem regarding accessibility of eye care is not addressed. The number of eye care professionals or trained optometrists is not adequate to address the needs of the population. Also, the eye care professionals congregate around urban areas, while most people live in rural areas. Therefore, even though people in rural areas have eye problems and require refractive correction they may not get their eyes tested due to non-availability of skilled eye care professional or affordability issues . Also, the existing refractors are very expensive which cannot be readily purchased by both rural and urban eye care professionals.

SUMMARY

One or more shortcomings of the prior art are overcome and additional advantages are provided through the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

The present disclosure includes a wearable device to determine corrective refractive parameters of a subject. The wearable device comprises a pair of tunable lens-systems housed within the wearable device. The pair of tunable lens-systems are controlled based on optical parameters. Further, the wearable device includes an alignment unit configured to align the pair of tunable lens-systems appropriately with respect to pupils of the subject based on alignment parameters. Furthermore, the wearable device includes a control unit configured to transmit the optical parameters received from at least one interface unit to the pair of tunable lens-systems and the alignment parameters received from the at least one interface unit to the alignment unit. The interface unit is associated with the wearable device. Further, the wearable device includes an indication unit configured to notify in response to occurrence of one or more events.

Further, the present disclosure provides a system comprising to determine corrective refractive parameters of a subject. The system comprises a wearable device and at least one interface unit. The wearable device comprises a pair of tunable lens-systems housed within the wearable device. The pair of tunable lens-systems are controlled based on optical parameters. Further, the wearable device includes an alignment unit configured to align the pair of tunable lens-systems appropriately with respect to pupils of the subject based on alignment parameters. Furthermore, the wearable device includes a control unit configured to transmit the optical parameters received from at least one interface unit to the pair of tunable lens-systems and the alignment parameters received from the at least one interface unit to the alignment unit. The interface unit is associated with the wearable device. Further, the wearable device includes an indication unit configured to notify in response to occurrence of one or more events. Furthermore, the at least one interface unit is configured to transmit the optical parameters to the pair of tunable lens-systems and the alignment parameters to the alignment unit.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:

FIG.1 shows an exemplary system to determine corrective refractive parameters of a subject in accordance with some embodiments of the present disclosure;

FIG.2A shows a detailed block diagram illustrating a wearable device in accordance with some embodiments of the present disclosure;

FIG.2B-1,2,3 and FIG.2C show an exemplary diagram illustrating attaching mechanisms of one or more accessories in accordance with some embodiments of the present disclosure;

FIG.2D and FIG.2E show an exemplary diagram illustrating an interface unit comprising physical input means in accordance with some embodiments of the present disclosure;

FIG.2F and FIG.2G show an exemplary diagram illustrating provisions for mounting the wearable device in accordance with some embodiments of the present disclosure; and

FIG.2I, FIG.2J, FIG.2K, FIG.2L and FIG.2M show an exemplary diagram illustrating adjustment apparatuses in accordance with some embodiments of the present disclosure.

It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and systems illustrated herein may be employed without departing from the principles of the disclosure described herein.

DESCRIPTION OF THE DISCLOSURE

In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
The present disclosure provides a wearable device and a system to determine the corrective refractive parameters of a subject. The wearable device comprises a pair of tunable lens-systems housed within the wearable device. The pair of tunable lens-systems are controlled based on optical parameters. As an example, the optical parameters may include, but not limited to, spherical power, cylindrical power, axis for cylindrical power, higher order optical aberration, voltage corresponding to the cylindrical power, voltage corresponding to the spherical power and their representations. Further, the wearable device includes an alignment unit configured to align the pair of tunable lens-systems appropriately with respect to pupils of the subject based on alignment parameters. As an example, the alignment parameters may include, but not limited to, Inter pupillary Distance (IPD) measurement, vertex distance, horizontal movement, vertical movement and the like. Furthermore, the wearable device includes a control unit configured to transmit the optical parameters received from at least one interface unit to the pair of tunable lens-systems and the alignment parameters received from the at least one interface unit to the alignment unit. The interface unit is associated with the wearable device. therefore, the interface unit may be present within the wearable device or may be present external to the wearable device. Further, the wearable device includes an indication unit configured to notify in response to occurrence of one or more events.

In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

FIG.1 shows an exemplary system to determine corrective refractive parameters of a subject in accordance with some embodiments of the present disclosure.

The system 100 comprises a wearable device 103, a communication interface 105 and an interface unit 107. In an embodiment, the wearable electronic device 103 may be used to determine corrective refractive parameters of a subject. As an example, the subject may include, but not limited to, human beings and animals. In one embodiment, the wearable electronic device 103 is mounted on head of the subject to determine the corrective refractive parameters. The wearable electronic device 103 communicates with the interface unit 107 through the communication interface 105. As an example, the communication interface 105 may be at least one of a wired communication interface and a wireless communication interface.

In an embodiment, the interface unit 107 may be at least one of a physical input means or a electronic input means. As an example, the physical input means may include, but not limited to, knobs, dials, sliders, keypads, haptic means such as touch pads and the like, inertial means such as nodding, tapping, gestures and the like. In an embodiment, a combination of one or more physical input means may be used in the interface unit 107. As an example, the electronic input means may include, but not limited to, a computing device such as a mobile, a tablet, a Personal Computer, a laptop and the like. In an embodiment, a combination of the physical input means and the electronic input means may be used in the interface unit 107. Further, the interface unit 107 is associated with the wearable device 103. Therefore, the interface unit 107 may be present inside the wearable device 103 or may be present external to the wearable device 103. In an embodiment, the interface unit 107 may include a processor 107a, an I/O interface 107b and a memory 107c. The interface unit 107 may receive and transmit information related to refraction testing via the I/O interface 107b. The processor 107a may perform one or more instructions stored in the memory 107c as disclosed in the present disclosure.

FIG.2A shows a detailed block diagram illustrating a wearable device in accordance with some embodiments of the present disclosure.

In an implementation, the wearable device 103 comprises a pair of tunable lens-systems 211, an accessory unit 212, an alignment unit 213, a control unit 215, an indication unit 217 and an adjustment unit 219. However, the wearable device 103 shall have all general features and shall have all the capabilities that are necessary to determine corrective refractive parameters of a subject. Additionally, the wearable device 103 may accommodate all the components described in the disclosure, to determine corrective refractive parameters of a subject.

In an embodiment, the pair of tunable lens-systems 211 includes a pair of tunable lens housed within individual lens housing units. As an example, the tunable lens may be a manually controllable tunable lens, an electrically controllable tunable lens, an electromechanically controllable tunable lens and the like. In another embodiment, the pair of tunable lens-systems 211 may comprise a combination of a tunable lens and alternative optics, such as non-tunable lens, solid lens, protective glass and the like. In an embodiment, the pair of tunable lens- systems 211 may be controlled based on optical parameters. As an example, the optical parameters may include, but not limited to, spherical power, cylindrical power, axis for cylindrical power, higher order optical aberration, voltage corresponding to the cylindrical power, voltage corresponding to the spherical power and their representations. The pair of tunable lens-systems 211 may be controlled independently or simultaneously based on the optical parameters to compensate eye refractive disorders. Further, eyes of the subject may be tested of the eye refractive disorders independently or simultaneously. As an example, the operator may test left eye separately, right eye separately or both left eye and right eye simultaneously.

In an embodiment, the accessory unit 212 may include one or more accessories related to the wearable device 103. As an example, the one or more accessories may include, but not limited to, diopter range extension lenses, a pin-hole, a Maddox rod, a red/green filter, an occluder, a prism, a stenopaic slit and a polarized filter. Further, the accessory unit 212 may adapt when equipment such as objective refractors, retinoscopes, smart vision chart display units and the like are attached. In an embodiment, the accessory unit 212 is present within the pair of tunable lens-systems 211. In a preferred embodiment, the one or more accessories may be detached from the accessory unit 212. In other words, the one or more accessories may not be permanently attached to the wearable device 103 as the one or more accessories may add on to bulkiness and weight of the wearable device 103. Therefore, as per requirement, the one or more accessories may be selected and attached/detached from the wearable device 103.

In an embodiment, the control unit 215 may automatically identify the one or more accessories that are attached/detached through one or more identifying units. The control unit 215 may include sensing units for sensing the one or more identifying units. As an example, the sensing units may include, but not limited to, a Radio-Frequency Identification (RFID) reader circuit and a Near Field Communication (NFC) reader circuit. As an example, the one or more identifying units may be related to RFID, NFC, magnetic, capacitive or inductive proximity sensing technologies and the like. As an example, consider a “polarized filter” comprising a RFID tag is attached to the accessory unit 212. The control unit 215 may sense the identifying unit i.e. the RF-ID tag attached to the “polarized filter” and identify that the accessory attached to the accessory unit 212 is the “polarized filter”. Further, as an example, consider an accessory “red/green filter” is attached to the accessory unit 212. The control unit 215 may automatically sense that the accessory attached is a “red/green filter”. The “red/green filter” is commonly used for performing binocular testing. Therefore, upon identifying that the accessory attached is the “red/green filter”, the control unit 215 may automatically trigger controls of an interface unit 107 associated with the wearable electronic device 103 to perform binocular testing. In an embodiment, the interface unit 107 may be present within the wearable device 103 or may be present external to the wearable device 103. The one or more accessories may be attached/detached from the accessory unit 212 based on, but not limited to, magnetic attachment mechanism, press-fit mechanism and slide fit mechanism. An exemplary representation of magnetic attachment mechanism, press-fit mechanism and slide fit mechanism is shown in the FIG.2B-1, FIG.2B-2 and FIG.2B-3 respectively. In an embodiment, the magnetic attachment mechanism may allow the one or more accessories to be attached/detached based on magnetic properties. Further, the press-fit mechanism may include interlocking constructs such as removable snap fit to ensure a firm coupling of the one or more accessories with the accessory unit 212. The interlocking constructs further ensure alignment and accuracy of the attachment of the one or more accessories. In an embodiment, the one or more accessories attached to the accessory unit 212 are aligned with the pair of tunable lens-systems 211. Further, the slide fit arrangement may allow the one or more accessories to be attached to the accessory unit 212 by sliding and locking movement of the one or more accessories.

One or more provisions may be provided in the accessory unit 212 that enables sliding of the one or more accessories. The one or more provisions may include proper clearance such that the one or more accessories are accurately aligned with the pair of tunable lens-systems 211. The accessory unit 212 provides alignment mechanism along with positioning of each of the one or more accessories attached to the accessory unit 212. As an example, certain accessories such as Maddox rod must be positioned exactly in the centre, and rotated exactly at 90 degrees, exactly at 180 degrees or the like. Therefore, the accessory unit 212 may include constructions that demand the one or more accessories to be placed only at specific angles and specific positions. As an example, the one or more accessories may fit into the accessory unit 212 when it is placed at a specific angle as shown in FIG.2C. If the one or more accessories are not placed at the specific angle, the attachment of the one or more accessories may be a failure leading to wrong alignment, wrong measurement and other similar errors. In another embodiment, the one or more accessories that are required by the wearable device 103 may be permanently integrated to the accessory unit 212.

In an embodiment, an alignment unit 213 may include one or more alignment apparatuses for aligning the pair of tunable lens-systems 211 appropriately with respect to pupils of the subject. The one or more alignment apparatuses may be controlled manually or electronically. The one or more alignment apparatuses may include provisions for adjusting Inter Pupillary Distance (IPD) and provisions for measuring IPD such as a knob, a scale and the like, provisions for performing vertical and horizontal movement of the pair of the pair of tunable lens-systems 211 such as lead screws and corresponding nuts, a slider and the like, provisions for adjusting distance between the pupils of the subject and the pair of tunable lens-system 211 (also referred to as vertex distance) such as a scale, a slider and the like, provisions for performing automatic adjustment such as a motor, linear actuators and the like. In an embodiment, the vertex distance may be measured by electronic provisions such as image capture and analysis, inbuilt Infrared (IR) sound, ultrasound distance detector and the like. Further, the scale used to measure the vertex distance may also act as a slide shutter to measure distance between the subject’s pupil and the respective lens in the pair of tunable lens-systems 211. In an embodiment, the alignment unit 213 may receive alignment parameters from the control unit 215. As an example, the alignment parameters may include, but not limited to IPD measurement, vertex distance, horizontal movement, vertical movement and the like.

In an embodiment, for controlling the alignment unit 213 manually, the control unit 215 is associated with the interface unit 107 comprising knobs as shown in FIG.2D. In an alternative embodiment, the control unit 215 may be associated with the interface unit 107 comprising the slider as shown in FIG.2E. The movement of knobs vary distance between the pair of tunable lens-systems 211 and the pupils of the subject, thereby controlling the alignment unit 213. Further, the electronic provisions present in the alignment unit 213 determines the IPD upon adjusting the pair of tunable lens-systems 211 corresponding to the pupils of the subject. The electronic provisions may enumerate number of rotations of the knob, thereby measuring the distance moved by the pair of tunable lens-systems 211. In another embodiment, for controlling the alignment unit 213 electronically, the control unit 215 directly transmits IPD measurement to the alignment unit 213. Based on the IPD measurement received, the provisions for automatic adjustment such as the motor, the linear actuator and the like present in the alignment unit 213 automatically move the pair of tunable lens-systems 211 to the IPD measurement. In an embodiment, the control unit 215 receives the IPD measurement from the interface unit 107. The IPD measurement may be further incremented or decremented by the interface unit 107. The interface unit 107 provides the incremented or decremented IPD measurement to the control unit 215 and the control unit 215 transmits the incremented or decremented IPD measurement to the provisions for automatic adjustment such as the motor, the linear actuator and the like to physically increment or decrement the IPD. Similarly, the vertex distance may be adjusted and measured either manually or electronically.

Further, the one or more alignment apparatuses may include one or more provisions to mount the wearable device 103 onto the head of the subject. The one or more provisions may be a headband, a spectacle type holder and the like. The one or more exemplary provisions for mounting the wearable device 103 are shown in FIG.2F and FIG.2G. The one or more provisions may include a dedicated surface that provides grip for the subject while mounting and unmounting the wearable device 103.

In an embodiment, the one or more provisions to mount the wearable device 103 may be adjusted by the adjustment unit 219. The adjustment unit 219 comprises one or more adjusting apparatuses configured to adjust the wearable device 103. The one or more adjusting apparatuses may include, but not limited to, a nose rest, one or more sliding components, one or more bands, hinges and the like. In an embodiment, the nose rest may be utilized to support weight of the wearable device 103 on nose of the subject as shown in FIG.2I. In another embodiment, hinges may be used as shown in FIG.2J through which the wearable device 103 hangs without any contact with the nose of the subject thereby avoiding contact and pressure on the nose of the subject. The one or more sliding components may be present in part of the headband that extends towards ears (also referred as temple component/s) of the subject as shown in the FIG.2K. The one or more sliding components enable increasing or decreasing size of the headband. Further, the one or more bands may allow the headband to be tightened or loosened around the head of the subject. In an embodiment, the headband may include two bands that grip the head of the subject from both sides as shown in FIG.2L. The two bands may be joined together using a linking device to form one continuous band. The linking device that joins the two bands together allows the tightening or loosening the headband around the head of the subject. In another embodiment, the headband may include a single band. As an example, the one or more bands may be made of, but not limited to, plastic, metal such as steel, rubber and fabric. Further, the one or more bands and the temple components may include an additional detachable component as shown in FIG.2M that may be required to adjust the wearable device 103 as per different size of the head of the subject. In an embodiment, the adjustment unit 219 may further include an eye shield that shields gaps between the wearable device 103 and the subject when the wearable device 103 is mounted by the subject.

Further, the control unit 215 may receive the optical parameters and the alignment parameters from the interface unit 107. Upon receiving, the control unit 215 transmits the optical parameters to the pair of tunable lens-systems 211 and the alignment parameters to the alignment unit 213. In an embodiment, the control unit 215 may interact with the pair of tunable lens-systems 211 via an Integrated Circuit (IC) and the like. The pair of tunable lens-systems 211 are controlled based on the optical parameters to determine the corrective refractive parameters for the subject. The alignment unit 213 controlled based on the alignment parameters is explained above in detail. In an embodiment, the interface unit 107 may be at least one of a physical input means or an electronic input means. As an example, the physical input means may include, but not limited to, knobs, dials, sliders, keypads, haptic means such as touch pads, inertial means such as nodding, tapping, gestures and the like. In an embodiment, a combination of one or more physical input means may be used in the interface unit 107. Further, as an example, the electronic input means may include, but not limited to, a computing device such as a mobile, a tablet, a Personal Computer, a laptop and the like. In an embodiment, a combination of the physical input means and the electronic input means may be used in the interface unit 107. Therefore, the control unit 215 may receive the optical parameters from the physical input means or the electronic input means. The control unit 215 may perform one or more operations on the optical parameters before transmitting the optical parameters to the pair of tunable lens-systems 211. As an example, the one or more operations may be converting the optical parameters, identifying ways of achieving spherical lens, cylindrical lens for the pair of tunable lens-systems 211 using the optical parameters and the like.

Further, the control unit 215 is associated with an inertial measurement unit (not shown in the figure) configured to track movement and orientation of the subject. As an example, the inertial measurement unit may include, but not limited to, gyroscopes, accelerometers and spirit-based levels. As an example, consider the subject is reading a newspaper. The inertial measurement unit immediately tracks the movement of the head of the subject to be downwards. Therefore, the control unit 215 may trigger one or more light sources present in the wearable device 103 to assist the subject in reading based on tracking information received from the inertial measurement unit. Further, the inertial measurement unit may be utilized for detecting mechanical damage of the pair of tunable lens-systems 211. In an embodiment, the control unit may detect whether the tunable-lens system has undergone damaging mechanical shock leading to a condition where calibration and/or internal alignment of optical components and the like are disturbed. In an embodiment, the control unit 215 through the inertial measurement unit continually monitors state of the wearable device 103. If the control unit 215 detects a sudden change in acceleration, it is interpreted to be a mechanical shock. In an embodiment, the amplitude of the shock may be assessed through the control unit 215 to determine if the shock would cause any damage to the pair of tunable lens-systems 211. Threshold value of the shock that may damage the pair of tunable lens-systems 211 may be determined experimentally. In an embodiment, the control unit 215 may send information related to the mechanical shock to the indication unit 217 which in turn informs the operator regarding the occurrence of mechanical shock. The occurrence of the mechanical shock may indicate that repair of the wearable device 103 is required. If the indication unit 217 is not powered when the mechanical shock occurs, the control unit 215 may store the occurrence of the mechanical shock and provide the indication to the operator when the indication unit 217 is powered.

Furthermore, the control unit 215 may be associated with one or more sensors. In an embodiment, the one or more sensors may include, but not limited to, a temperature sensor and a proximity sensor. In an embodiment, the pair of tunable lens-systems 211 may be susceptible to thermal expansion that leads to loss of accuracy. Therefore, the temperature sensor continuously measures ambient temperature to improve accuracy in different temperature environments.

Further, the wearable device 103 is powered by a power source. In an embodiment, the power source may be cordless such as a battery or a wired power source. In operation, the wearable device 103 is by default in a standby mode. In an embodiment, the standby mode may include shutting down the power supply completely or partially. When the proximity sensor detects mounting of the wearable device 103 by the subject based on proximity of the wearable device 103 with the subject, the proximity sensor activates the control unit 215 from the standby mode. Furthermore, when the wearable device 103 is mounted by the subject, the proximity sensor turns ON the pupil-illuminating light sources and automatically sets the pair of tunable lens-systems 211 to zero dioptre (0D).

In an embodiment, the indication unit 217 may notify the subject and an operator of the interface unit 107 in response to occurrence of one or more events. The indication unit 217 may include one or more indicators to notify the subject and the operator. As an example, the one or more indicators may include, but not limited to, visual indicators such as Light Emitting Diodes (LEDs) of various colours, various blink intervals, intensity, integrated display and the like, sound indicators such as voice instructions, beeps of varying frequency, loudness, sound intervals and the like, electric indicators such as mild electric shock, nervous system stimulation and the like, haptic indicators such as vibration, mechanical application of force such as tap on the head and the like. Further, as an example, the one or more events may include, but not limited to, varying the optical parameters, comparing the optical parameters, asking questions to the subject regarding the optical parameters, correct and wrong mounting of the wearable device 103, eye being tested currently and changes associated with the eye being tested and malfunctioning of the wearable device 103. As an example, comparing the optical parameters may include providing one beep to indicate optical parameter A and two beeps to indicate optical parameter B, thereby indicating the subject regarding the optical parameters being applied. As an example, asking questions to the subject regarding the optical parameters may include providing verbal instructions such as “is the optical parameter getting better or worse” or “optical parameter A better than the optical parameter B”. As an example, the correct and wrong mounting of the wearable device 103 includes checking whether the wearable device 103 is mounted properly on the head of the subject, checking if the alignment has changed and the like. As an example, the eye being tested currently may include, indicating transition from left eye-to-right eye, right eye-to-left eye and the like. As an example, malfunctioning of the wearable device 103 includes condition when the pair of tunable lens-systems 211 is out of calibration, unsuitable environmental conditions and the like.

Consider a scenario where the corrective refractive parameters of the subject may be determined using electronic input means of the interface unit 107. In this scenario, consider the interface unit 107 is a mobile phone which is operated by an operator. Further, this scenario uses a wearable device 103 comprising a pair of electrowetting tunable lens that are housed in individual housing units. Each electrowetting tunable lens comprises one or more electrodes for applying suitable voltage. In this scenario, consider that each of the electrowetting tunable lens comprises 8 electrodes. Each of the one or more electrodes are connected to a driver IC. When a certain voltage value is applied, the one or more electrodes are electrically driven by the driver ICs. Each voltage value is associated with a predetermined dioptre value of the tunable liquid lenses. Therefore, when the voltage applied to the one or more electrodes is varied, the curvature of the tunable liquid lenses changes which in turn changes the power of the tunable liquid lenses. Upon applying the same voltage to each of the one or more electrodes, a spherical lens is emulated by the tunable liquid lenses. The power of the spherical lens depends on the voltage applied to each of the one or more electrodes. If the voltage is applied in a symmetric pattern to the one or more electrodes, then a cylindrical lens is emulated by the tunable liquid lenses. The power of the cylindrical lens depends on the combination in which the voltage is applied to the one or more electrodes across an angle.

Therefore, in this scenario, when the wearable device 103 is mounted by the subject, the proximity sensor activates the control unit 215. The wearable device 103 is adjusted accurately on the head of the subject using the adjustment unit 219 for ensuring firm fit of the wearable device 103. Further, the control unit 215 provides necessary alignment parameters to the alignment unit 213 to align the pair of tunable lens-systems 211 with the pupils of the subject. Upon aligning, firstly the operator selects the eye to be tested i.e. left eye or right eye or both simultaneously. The indication unit 217 may indicate that the left eye is being tested via an LED. Upon selecting the eye to be tested, the operator selects a certain optical parameter via a refractor application installed in the mobile phone. Consider the optical parameter selected was a spherical power of 0.5 dioptre. The interface unit 107 transmits the dioptre value to the control unit 215. The control unit 215 converts the dioptre value into a voltage value corresponding to the dioptre value using a predefined technique or a preloaded mapping table . The voltage value thus obtained may be analysed to understand that the voltage value corresponds to a spherical power. Therefore, the control unit 215 transmits the voltage value to the driver IC. The driver IC applies the voltage value equally to each of the one or more electrodes present on the left tunable lens in the pair of tunable lens-systems 211. Upon applying the voltage value to each of the one or more electrodes, the power of tunable lens changes to 0.5 dioptre. Further, the operator may ask questions such as “is the vision clear?”. If the subject is satisfied with the power of the tunable lens, the operator may select the spherical power of 0.5 dioptre as the corrective refractive parameter of the subject and generate a prescription in the mobile phone. In an embodiment, the prescription may be transmitted to the subject for his reference. If the subject is not satisfied with the power of the tunable lens, an indication is provided to the operator. Further, the operator re-iterates the process by varying the optical parameters until the subject is satisfied with the power of the tunable lens.

Consider a scenario where the corrective refractive parameters of the subject may be determined using physical input means of the interface unit 107. In this scenario, consider the interface unit 107 is a knob present on the wearable device 103 which is operated by an operator. When the wearable device 103 is mounted by the subject, the proximity sensor activates the control unit 215. Firstly, the operator selects the eye to be tested i.e. left eye or right eye or both. The indication unit 217 may indicate that the left eye is being tested via an LED. In an embodiment, the alignment may be performed manually by moving the one or more alignment apparatuses. Upon aligning, the pair of tunable lens-system 211 is tuned by performing manual rotation of the knob which is directly coupled with the optical parameters through a mechanical compression ring or the like. As an example, when the knob is rotated clockwise, the spherical power of the lens increases. The knob further contains a pointer label which may be coupled to the scale that acts as a display to the operator. As the knob is rotated clockwise and the spherical power changes, and the pointer on the scale indicates the achieved spherical power. When the spherical power is varied, the subject may be indicated of the change in the spherical power by an intentional mechanical clicking noise produced by the knob upon rotating. Further, the operator may ask questions such as “is the vision clear?”. If the subject is satisfied with the power of the tunable lens, the operator may select the achieved spherical power as the corrective refractive parameter of the subject and manually generates a prescription. If the subject is not satisfied with the power of the tunable lens, an indication is provided to the operator. Further, the operator re-iterates the process by further rotating the knob to vary the optical parameters until the subject is satisfied with the power of the tunable lens. In an embodiment, an electronic circuit may be incorporated with the knob to provide other types of feedback to the subject.

Advantages of the present disclosure

The present disclosure provides a wearable device to determine corrective refractive parameters of a subject.

The present disclosure provides a feature wherein one or more accessories attached to the wearable device get automatically aligned with the pair of tunable lens-systems. Further, the one or more accessories attached or detached from the wearable device are automatically identified based on identifying units related to RFID, NFC and the like. Detecting the attached accessory provides the advantage of streamlining the subjective refraction testing process.

The present disclosure provides a feature wherein the wearable device does not involve mechanical handling of lenses. Therefore, the present disclosure eliminates stress injuries caused due to interchanging of lens. Furthermore, the use of fewer lenses reduces the optical distortion caused by stacking several lenses.

The present disclosure comprises a proximity sensor that activates the wearable device when mounted by the subject. Therefore, the wearable devices utilizes very little power.

The present disclosure provides an easier and efficient way for the subject and/or the operator to adjust and measure the pupillary distance and the vertex distance.

The present disclosure provides various adjustment mechanisms to ensure a comfortable fit of the wearable device. Further, a nose rest present in the wearable device may be substituted using hinges that eliminates pressure exerted on nose of the subject by the nose rest.

The present disclosure provides one or more indicators in the indication unit that notifies in response to occurrence of one or more events thus assisting the operator and the subject for accurate results.
The present disclosure provides a feature of intentional indication. In a condition when the tunable lens-systems use the principle of electrowetting, the process of determining the corrective refractive parameters may be completely noiseless. In such conditions, the subject may find it difficult to distinguish between subsequent steps of the subjective refraction process. Therefore, the intentional feedback provided in the system handles the issue of a noiseless process.
The present disclosure provides complete flexibility for switching between different correction techniques such as spherical correction technique, cylindrical correction technique, binocular correction technique and near-vision mode correction technique, any number of times and in any order, while testing one eye at a time or both the eyes simultaneously.

The present disclosure is battery powered, compact, wearable, provides quick results, portable and is user friendly. Further, the wearable device in the present disclosure can be carried to locations such as rural areas, areas that lack electricity and the like for refraction testing.

A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.

When a single device or article is described herein, it will be readily apparent that more than one device/article (whether or not they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device/article may be used in place of the more than one device or article or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of the invention need not include the device itself.

The specification has described a wearable device and a system to determine corrective refractive parameters of a subject. The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that on-going technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words "comprising," "having," "containing," and "including," and other similar forms are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

Referral Numerals:

,CLAIMS:We claim:

1. A wearable device (103) to determine corrective refractive parameters of a subject, the wearable device (103) comprising:

a pair of tunable lens-systems (211) housed within the wearable device (103), wherein the pair of tunable lens-systems (211) are controlled based on optical parameters;

an alignment unit (213) configured to align the pair of tunable lens-systems (211) appropriately with respect to pupils of the subject based on alignment parameters;
a control unit (215) configured to transmit the optical parameters received from at least one interface unit (107) to the pair of tunable lens-systems (211) and the alignment parameters received from the at least one interface unit (103) to the alignment unit (213), wherein the interface unit (107) is associated with the wearable device (103); and
an indication unit (217) configured to notify in response to occurrence of one or more events through one or more indicators.

2. The wearable device (103) as claimed in claim 1, wherein the alignment unit (213) comprises one or more alignment apparatuses.

3. The wearable device (103) as claimed in claim 1, wherein the one or more indicators are at least one of sound indicators, visual indicators, electric indicators and haptic indicators.

4. The wearable device (103) as claimed in claim 1, wherein the control unit is further configured to perform one or more predefined operations on the optical parameters.

5. The wearable device (103) as claimed in claim 1 further comprises a proximity sensor configured to:
detect mounting of the wearable device (103) by the subject based on proximity of the wearable device with the subject; and

activate the control unit from a standby mode when the wearable device (103) is detected to be proximal to the subject.

6. The wearable device (103) as claimed in claim 1, wherein the control unit (215) is further associated with an inertial measurement unit configured to track movement and orientation of the subject.

7. The wearable device (103) as claimed in claim 6, wherein the inertial measurement unit is further configured to detect mechanical damage of the pair of tunable lens-systems (211).

8. The wearable device (103) as claimed in claim 1 further comprises an eye shield configured to prevent undesirable light from reaching eyes of the subject.

9. The wearable device (103) as claimed in claim 1 further comprises at least one temperature sensor configured to measure ambient temperature.

10. The wearable device (103) as claimed in claim 1 further comprises an accessory unit (212) aligned with the pair of tunable lens-systems (211), wherein the accessory unit (212) comprises one or more accessories related to the wearable device (103).

11. The wearable device (103) as claimed in claim 10, wherein the one or more accessories are detachable from the accessory unit (212).

12. The wearable device (103) as claimed in claim 11, wherein the one or more accessories are automatically identified through one or more identifying units when attached or detached from the accessory unit (212).

13. The wearable device (103) as claimed in claim 1 further comprises a power source to power the wearable device (103).

14. The wearable device (103) as claimed in claim 1 further comprises an adjustment unit (219) with one or more adjusting apparatuses configured to adjust the wearable device (103) mounted on the subject.

15. The wearable device (103) as claimed in claim 1 further comprises a slide shutter to measure distance between the subject’s pupil and the respective lens in the pair of tunable lens-systems (211).

16. A system (100) to determine corrective refractive parameters of a subject, the system (100) comprising:

a wearable device (103) comprising:
a pair of tunable lens-systems (211) housed within the wearable device (103), wherein the pair of tunable lens-systems (211) are controlled based on optical parameters;
an alignment unit (213) configured to align the pair of tunable lens-systems (211) appropriately with respect to pupils of the subject based on alignment parameters;
a control unit (215) configured to transmit the optical parameters received from at least one interface unit (107) to the pair of tunable lens-systems (211) and the alignment parameters received from the at least one interface unit (107) to the alignment unit (213), wherein the interface unit is associated with the wearable device; and
an indication unit (217) configured to notify in response to occurrence of one or more events through one or more indicators; and
the at least one interface unit (107) configured to transmit the optical parameters to the pair of tunable lens-systems (211) and the alignment parameters to the alignment unit (213).
17. The system (100) as claimed in claim 16, wherein the interface unit (107) is further configured to transmit prescription of the subject to one or more end users.

18. The system (100) as claimed in claim 16, wherein the interface unit (107) is further configured to receive information related to the wearable device (103) from the control unit (215).