Method and system for measuring optical properties of contact lenses
阅读说明:本技术 用于测量隐形眼镜的光学特性的方法和系统 (Method and system for measuring optical properties of contact lenses ) 是由 F·R·布莱克伯恩 J·黑兹尔 P·马丁 于 2017-12-28 设计创作,主要内容包括:一种确定隐形眼镜(200)的透射率的方法,包括以下步骤:利用强度测量设备(400)获得由眼表(100)反射的电磁辐射的第一强度的测量结果;将隐形眼镜(200)定位成与眼表(100)直接接触;利用强度测量设备(400)获得透射通过隐形眼镜(200)的由被隐形眼镜(200)覆盖的眼表(100)的区域(110)反射的电磁辐射的第二强度的测量结果;以及使用第一强度和第二强度的测量结果来计算透射率。(A method of determining the transmittance of a contact lens (200), comprising the steps of: obtaining a measurement of a first intensity of electromagnetic radiation reflected by the ocular surface (100) with an intensity measurement device (400); positioning a contact lens (200) in direct contact with an ocular surface (100); obtaining a measurement of a second intensity of electromagnetic radiation transmitted through a region (110) of the contact lens (200) of the ocular surface (100) covered by the contact lens (200) with an intensity measurement device (400); and calculating the transmittance using the measurements of the first intensity and the second intensity.)
1. A method for determining the transmittance of electromagnetic radiation through a contact lens (200) in direct contact with an ocular surface (100), comprising:
measuring a first intensity of radiation reflected by at least a portion of the ocular surface (100) with an intensity measurement device (400);
positioning a contact lens (200) to cover and be in direct contact with at least a portion of an ocular surface (100);
measuring a second intensity of radiation transmitted through the contact lens (200) reflected by at least one area (110) of the ocular surface (100) covered by the contact lens (200) with an intensity measurement device (400); and
using the measurements of the first and second intensities, the transmittance of the electromagnetic radiation through the contact lens (200) is calculated.
2. The method of claim 1, further comprising:
determining an intensity value due to dark current on the intensity measurement device (400); and
the transmittance of electromagnetic radiation through the contact lens (200) is calculated according to the following formula:
wherein:
TCorris the transmittance of electromagnetic radiation through the contact lens (200);
IOis a measurement of a first intensity;
ITis a measurement of the second intensity; and
d is an intensity value due to dark current on the intensity measurement device (400).
3. The method of claim 1 or 2, further comprising:
measuring a third intensity of radiation reflected from the secondary location (150) simultaneously with the measuring of the first intensity, wherein the at least one region (110) is different from the secondary location (150);
measuring a fourth intensity of radiation reflected from the auxiliary location (150) simultaneously with the measuring of the second intensity;
comparing the third intensity and the fourth intensity to determine a change in radiation intensity between the time of measurement of the first intensity and the third intensity and the time of measurement of the second intensity and the fourth intensity; and
the comparison between the third intensity and the fourth intensity is used to compensate for variations in radiation intensity between the time of measurement of the first intensity and the third intensity and the time of measurement of the second intensity and the fourth intensity when calculating the transmittance of the electromagnetic radiation through the contact lens (200).
4. The method according to any one of claims 1 to 3, wherein the intensity measurement device (400) is configured to measure the intensity of the electromagnetic radiation within the electromagnetic radiation spectrum in a wavelength range comprising 1nm to 1,000nm, preferably 380-780 nm.
5. The method according to any one of claims 1 to 4, wherein the intensity measurement device (400) is configured to measure the intensity of the electromagnetic radiation within an electromagnetic radiation spectrum comprising a wavelength range of 460 ± 20 nm.
6. The method according to any one of claims 1 to 5, wherein the intensity measurement device (400) is configured to measure the intensity of the electromagnetic radiation within an electromagnetic radiation spectrum comprising a wavelength range of 555 ± 20 nm.
7. The method according to any one of claims 1 to 6, wherein the intensity measurement device (400) is configured to measure the intensity of the electromagnetic radiation within an electromagnetic radiation spectrum comprising a wavelength range of 635 ± 20 nm.
8. The method of any one of claims 1 to 7, wherein the measurements of the first and second intensities are from a wavelength range selected from the group comprising 460 ± 20nm, 555 ± 20nm, and 635 ± 20 nm.
9. The method of any of claims 1 to 8, further comprising:
before measuring the first intensity and the second intensity, a filter (450), preferably a three-wavelength notch filter (450), is applied on a detector of the intensity measuring device (400).
10. The method of claim 9, wherein the filter (450) is centered around a wavelength selected from the group consisting of 460 ± 20nm, 555 ± 20nm, and 635 ± 20 nm.
11. The method according to any one of claims 1 to 10, wherein the ocular surface (100) comprises at least a part of a human eye, preferably at least a part of a sclera (120) of the eye.
12. The method of any one of claims 1 to 11, wherein the contact lens (200) is a photochromic contact lens (200) or a tinted contact lens (200).
13. The method of claim 12, further comprising:
the value of the second intensity is measured over a substantially central portion or a peripheral portion of the contact lens (200).
14. The method of any one of claims 1 to 13, wherein the contact lens (200) is a photochromic contact lens (200), and the method comprises:
selecting a desired wavelength range of electromagnetic radiation;
selecting a desired activation level for a photochromic contact lens (200); and
exposing the photochromic contact lens (200) to actinic radiation until the photochromic contact lens (200) reaches a desired activation level, wherein the ocular surface (100) comprises the eye, wherein the at least one region (110) is located on a sclera (120) of the eye, wherein the intensity measurement device (400) is an imaging device configured to record electromagnetic radiation intensity data within a desired wavelength range, wherein measuring a first intensity of radiation reflected by the ocular surface (100) with the intensity measurement device (400) comprises taking a first image of the region (110) of the sclera (120) with the imaging device (400), wherein positioning the photochromic contact lens (200) to cover the ocular surface (100) comprises covering the region (110) of the sclera (120) with the activated photochromic contact lens (200), wherein measuring a second intensity of radiation reflected by the region (110) of the ocular surface (100) covered by the photochromic contact lens (200) with the intensity measurement device (400) comprises causing the photochromic contact lens (200) to cover the region (110) of the ocular surface to be activated Maximizing the visibility of the region (110) of the sclera (120), and taking a second image of the region (110) of the sclera (120) with an imaging device (400), an
Wherein calculating the transmittance of electromagnetic radiation through the photochromic contact lens (200) using the measurements of the first intensity and the second intensity comprises:
recording a first set of electromagnetic radiation intensity data for a desired wavelength range acquired from a first image;
recording a second set of electromagnetic radiation intensity data for the desired wavelength range acquired from the second image;
inputting the first set of data and the second set of data into a database; and
a processor is used to determine the transmittance of electromagnetic radiation through the photochromic contact lens.
15. The method of claim 1, wherein the contact lens (200) is positioned to cover the ocular surface (100) prior to measuring the first intensity and the second intensity, wherein measurements of the first intensity and the second intensity are taken from the same image, wherein the first intensity is measured from a portion of the ocular surface (100) not covered by the contact lens (200), wherein the second intensity is measured from a portion of the ocular surface (100) covered by the contact lens (200), and the method further comprises:
converting the measurement of the first intensity into CIE XYZ values;
converting the measurement of the second intensity into CIE XYZ values; and
the transmittance is determined according to the following formula:
wherein:
TYis the transmittance of the contact lens (200) as determined from the CIE Y value;
Yuncoveredis a Y value of a portion of the image of the ocular surface (100) in which the ocular surface (100) is not covered by the contact lens (200); and
Ycoveredis the Y value of the portion of the image of the eye table (100) in which the eye table (100) is covered by the contact lens (200).
Technical Field
The present invention relates to a method and a measuring system for determining optical properties of contact lenses, such as photochromic contact lenses (contact lenses), under real world conditions.
Background
Optical elements that absorb electromagnetic radiation in the visible region of the electromagnetic spectrum are used in a variety of articles such as contact lenses. A "contact lens" is expressly defined herein as a device that resides physically in or directly on the eye. "directly on …" means "in direct contact with …". It should be understood that the terms "directly on …" and "directly in contact with …" also include the presence of a tear film between the contact lens and the eye.
Contact lenses that absorb electromagnetic radiation improve the wearer's viewing comfort and enhance the wearer's ability to see objects in bright conditions. Examples of electromagnetic radiation absorbing contact lenses include fixed tint (fixed tint) contact lenses and photochromic (photochromic) contact lenses.
Photochromic contact lenses change tint in response to electromagnetic radiation of a particular wavelength. Photochromic contact lenses provide improved vision and comfort to the wearer when exposed to bright light conditions, but return to a non-absorbing or less absorbing state in low light conditions. Photochromic contact lenses provide comfort and viewing convenience under a range of lighting conditions and eliminate the need to switch between pairs of lenses when moving between an indoor/low light position and an outdoor/bright light position.
Known methods for testing or quantifying the amount of light transmitted by contact lenses, such as photochromic contact lenses, use conventional optical platforms under laboratory conditions. Photochromic contact lenses are typically activated by exposure to ultraviolet radiation and mounted on an optical platform for testing. While optical platforms are well suited for laboratory conditions, they may not provide an accurate determination of the optical and/or aesthetic properties of photochromic contact lenses under real-world conditions, such as when actually worn under ambient lighting conditions. The color or tint/darkness of the activated photochromic contact lens may appear different when actually worn by a user under real world conditions as compared to when the contact lens is measured on an optical platform under laboratory conditions. Moreover, the perceived aesthetics of photochromic contact lenses may vary when actually worn due to the shading characteristics and color variations of the human eye.
The light transmission of photochromic contact lenses varies based on the amount and duration of actinic radiation received. If a photochromic contact lens is first activated by the wearer under ambient conditions and then transferred to a laboratory optical bench for measurement, the activation level of the photochromic contact lens may vary between the time the photochromic contact lens is activated and the time the photochromic contact lens has been secured to the optical bench for measurement. Existing methods of maintaining activation under laboratory conditions, such as exposing photochromic contact lenses to xenon-arc lamps, may not accurately reproduce real-world conditions.
The ability to determine the optical characteristics of contact lenses (e.g., activated photochromic contact lenses) outside of a conventional laboratory environment has several applications, including quality control and marketing. Testing photochromic contact lenses under real world conditions provides useful data regarding the comfort and reliability experienced by the wearer. In addition, the ability to accurately determine the real world characteristics of photochromic contact lenses can provide a quantifiable or qualitative basis for the purchaser to determine whether various photochromic contact lenses are used in their geographic location or for their intended purpose.
Accordingly, it would be desirable to provide a method and/or system for measuring optical properties of contact lenses, such as photochromic contact lenses, under real world conditions. There is a further need for a portable method and/or system.
Disclosure of Invention
A method for determining the transmittance of electromagnetic radiation through a contact lens, comprising: measuring a first intensity of electromagnetic radiation reflected by the ocular surface; positioning a contact lens directly on and covering a portion of an ocular surface; measuring a second intensity of electromagnetic radiation transmitted through the contact lens that is reflected by an area of the ocular surface covered by the contact lens; and calculating the transmittance of the electromagnetic radiation through the contact lens using the measurements of the first intensity and the second intensity.
A method for determining the transmittance of electromagnetic radiation through a photochromic contact lens, the method comprising: positioning an unactivated photochromic contact lens directly on and covering a portion of an ocular surface; measuring a first intensity of electromagnetic radiation reflected by an area of the ocular surface covered by the unactivated photochromic contact lens; activating a photochromic contact lens on the ocular surface; measuring a second intensity of electromagnetic radiation transmitted through the photochromic contact lens reflected by the area of the ocular surface covered by the activated photochromic contact lens; and calculating the transmittance of the electromagnetic radiation through the photochromic contact lens using the measurements of the first intensity and the second intensity.
A method for determining the transmittance of electromagnetic radiation through a contact lens, comprising: measuring a first intensity of electromagnetic radiation transmitted through an activated contact lens reflected by an area of an ocular surface covered by the activated contact lens; measuring a second intensity of electromagnetic radiation reflected by an area of the ocular surface not covered by the contact lens; converting the first measurement result and the second measurement result into CIE color coordinates; and calculating the transmittance of the electromagnetic radiation through the contact lens using the difference in CIE color coordinates.
The contact lens is in direct contact with the ocular surface.
The measurement of the first intensity and the second intensity may be performed using a photographic imaging device.
The electromagnetic radiation may be one or more wavelengths of visible light, or may be one or more wavelength ranges of visible light.
A method for determining the transmittance of a photochromic contact lens at a desired activation level, comprising: selecting a desired wavelength range of electromagnetic radiation; selecting a desired activation level for a photochromic contact lens; exposing the photochromic contact lens to actinic radiation in a desired wavelength range until the photochromic contact lens reaches a desired activation level; maximizing visibility of an area of the sclera of the eye; capturing a first image of a region of the sclera with an imaging device, wherein the imaging device is configured to record light intensity data within the selected wavelength range; recording a first set of electromagnetic radiation intensity data for the selected wavelength range acquired from the first image; covering an area of the sclera with an activated photochromic contact lens; capturing a second image of a region of the sclera with the imaging device; recording a second set of electromagnetic radiation intensity data for the selected wavelength range acquired from the second image; inputting the first set of data and the second set of data into a database; and determining, using a processor, a transmittance of the photochromic contact lens.
Drawings
FIG. 1 is a side schematic view of an intensity measurement system including an intensity measurement device for measuring intensity data of electromagnetic radiation reflected from an ocular surface;
FIG. 2 is a schematic front view of an eye table illustrating measurement zones;
FIG. 3 is a schematic front view of an eye table illustrating another measurement zone;
FIG. 4 is a schematic front view of the ocular surface of FIG. 2 showing a contact lens in direct contact with a portion of the ocular surface;
FIG. 5 is a schematic front view of the ocular surface of FIG. 3 showing a contact lens in direct contact with a portion of the ocular surface;
FIG. 6 is a schematic front view of an eye table showing another exemplary positioning of a contact lens;
FIG. 7 is a block diagram of an exemplary measurement method of the present invention; and
fig. 8 is a block diagram of another exemplary measurement method of the present invention.
Detailed Description
As used in the specification and in the claims, the singular form of "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.
Spatial or directional terms, such as "left", "right", "up", "down", and the like, relate to the invention as it is shown in the drawings. The invention may, however, assume various alternative orientations and, accordingly, such terms are not to be considered as limiting.
All numbers used in the specification and claims are to be understood as being modified in all instances by the term "about". "about" refers to a range of plus or minus ten percent of the stated value.
The term "such as" should be understood as non-limiting. That is, elements recited after "such as" should be understood as non-limiting examples of the recited features.
All ranges disclosed herein are inclusive of the beginning and ending range values and any and all subranges subsumed therein. Ranges disclosed herein refer to average values within the specified range.
With respect to the positional relationship between examples of the ocular surface and examples of the contact lens, the use of the term "covered by …" or "covering" means direct contact. For example, the area of the ocular surface covered by the contact lens means that the contact lens is in direct contact with the ocular surface.
With respect to the positional relationship between examples of the ocular surface and examples of the contact lens, the use of the term "uncovered" or "uncovered" means that the ocular surface is not "covered" by the contact lens in the frame of reference of the imaging device.
The term "polymer" or "polymerized" includes oligomers, homopolymers, copolymers, polymer blends (i.e., mixtures of homopolymers or copolymers), and terpolymers, e.g., polymers formed from two or more types of monomers or polymers.
The term "ultraviolet radiation" refers to electromagnetic radiation having a wavelength in the range of 100 nanometers (nm) to less than 380 nm. The term "visible radiation" or "visible light" refers to electromagnetic radiation having a wavelength in the range of 380nm to 780 nm. The term "infrared radiation" refers to electromagnetic radiation having a wavelength in the range of greater than 780nm to 1,000,000 nm.
All documents cited herein are "incorporated by reference" in their entirety.
"at least" means "greater than or equal to". "not greater than" means "less than or equal to".
Wavelength values are in nanometers (nm), unless otherwise indicated.
The term "comprising" is synonymous with "including".
The terms "actinic radiation" and "actinic light" refer to electromagnetic radiation capable of causing a response in a material, such as the conversion of a photochromic material from one activated state to another.
The term "photochromic" refers to having an absorption spectrum for at least visible radiation that changes in response to the absorption of at least actinic radiation.
The terms "first," "second," and the like, when referring to different conditions, are not intended to indicate any particular order or temporal order, but rather indicate different conditions or properties. To illustrate, the first and second states of the photochromic contact lens may differ with respect to at least one optical property, such as absorption or linear polarization of visible and/or Ultraviolet (UV) radiation. For example, a photochromic contact lens may be clear in a first state and colored in a second state. Alternatively, the photochromic contact lens can have a first color in the first state and a second color in the second state.
The term "optical" means related to or associated with light and/or vision.
The term "fixed hue" means having a colorant that is non-photosensitive, i.e., that has no physical or chemical response to electromagnetic radiation with respect to its visually observed color.
The term "transparent" means that the material has the property of transmitting light without significant scattering so that objects located outside are visible.
The term "activated" means that the optical device has been exposed to a condition, such as actinic radiation, for a sufficient period of time such that the contact lens transitions from a first activation state to a second activation state with respect to at least one optical property, such as absorption or linear polarization of visible and/or Ultraviolet (UV) radiation.
The term "desired level of activation" may be a quantitative or qualitative determination. The desired activation level of the photochromic contact lens may be the activation level that the device has reached by exposure to directional light or ambient light in a particular environment (wavelength or range of wavelengths) for a selected period of time.
CIE color coordinates (e.g., X, Y, Z) means coordinates conforming to the CIE XYZ color system specified by the international commission on illumination, including the CIE color matching function XYZ. The CIE color coordinates may conform to CIE XYZ 1931, 1664, and/or 2004 formats.
Discussion of the invention may describe certain features as being "particularly" or "preferably" within certain limits (e.g., "preferably," "more preferably," or "even more preferably" within certain limits). It is to be understood that the invention is not limited to these specific or preferred limitations, but encompasses the full scope of the disclosure.
The present invention includes, consists of, or consists essentially of the following aspects of the invention in any combination. Aspects of the invention are illustrated in separate drawings. However, it should be understood that this is done merely for ease of illustration and discussion. In the practice of the invention, one or more aspects of the invention illustrated in one drawing may be combined with one or more aspects of the invention illustrated in one or more other drawings.
Fig. 1 is a schematic representation of a measurement system 10 of the present invention. The measurement system 10 includes an
The light source 300 emits electromagnetic radiation at one or more wavelengths or within one or more wavelength ranges. The electromagnetic radiation may be visible light. Light source 300 may also emit electromagnetic radiation in one or more other spectrums of electromagnetic radiation, such as the Infrared (IR) and/or Ultraviolet (UV) spectrums. Although not shown in the drawings, a plurality of light sources 300 may be used. If there are multiple light sources 300, the light sources 300 may emit electromagnetic radiation of the same wavelength or wavelength range, or some of the light sources 300 may emit electromagnetic radiation of a different wavelength or wavelength range than other of the light sources 300. An example of the light source 300 includes the sun, in which case the electromagnetic radiation would be ambient outdoor light. Alternatively, the light source 300 may be an artificial light source, such as an incandescent light bulb, a fluorescent lamp, a compact fluorescent lamp, or any other light source that emits electromagnetic radiation in a desired spectrum.
The
Referring to fig. 1, electromagnetic radiation (e.g., visible light) emitted from light source 300 is reflected off of one or more areas of
Image data, including data regarding light intensity and location, may be stored in an internal memory of the imaging device 400. Alternatively, the image data may be stored in a removable or external memory, or in any other manner known in the art.
The imaging device 400 is configured to acquire image data comprising intensity data of electromagnetic radiation of one or more selected wavelengths or one or more wavelength ranges. For example, imaging device 400 may be configured to acquire image data including intensity data of electromagnetic radiation at one or more selected wavelengths or one or more wavelength ranges in the range of 1nm to 1,000 nm. For example, the imaging device 400 may be configured to acquire image data including intensity data of visible light of one or more selected wavelengths or one or more wavelength ranges. For example, the imaging device 400 may acquire data regarding the intensity of electromagnetic radiation in the red, green, and blue ranges. Alternatively or additionally, the imaging device 400 may acquire intensity data of electromagnetic radiation in the cyan, yellow, green, and/or magenta ranges. Other wavelength ranges may also be used. Those skilled in the art will appreciate that the various manufacturers and imaging devices define different ranges of these colors, and that the specified wavelengths or wavelength ranges and some ranges for each color may overlap. Exemplary ranges for red, green and blue are 635 + -20 nm, 555 + -20 nm and 460 + -20 nm, respectively. Any range or combination of wavelength ranges in the visible spectrum including wavelengths between about 380-780nm may be used.
A specified wavelength range of visible light can be selected from which data can be acquired. These wavelength ranges may correspond to the color of a given photochromic dye present in the optical element to be tested, such as a photochromic contact lens. The wavelengths may be any combination of wavelengths and can be defined by using filters. A filter 450 corresponding to a selected or desired wavelength range or ranges of electromagnetic radiation (e.g., visible light) may be placed between the
Fig. 2 and 3 are schematic representations of an eye table 100 applied on the x-axis and y-axis. These figures illustrate an
Fig. 4 and 5 are schematic representations of the
Referring to the example schematically depicted in fig. 4 and 5, a second measurement is made of the intensity of electromagnetic radiation (e.g., visible light) transmitted through the contact lens 200 that is reflected by the
When the imaging apparatus 400 captures image data over all or at least a portion of the surface area of the contact lens 200, the intensity values of the entire contact lens 200 can be compared. Such a comparison is useful because it allows for identifying differences in transmittance across the contact lens 200. This indicates the location of certain image defects on the contact lens 200. In this case, the
With particular reference to fig. 2 and 4, the contact lens 200 may cover portions of the
Fig. 5 depicts an example in which the contact lens 200 is positioned to cover a portion of the
Referring to fig. 1-5, to compare intensity data between the first measurement and the second measurement, position data of the
To ensure that intensity data acquired from the
Fig. 6 illustrates an example of positioning a contact lens 200 (e.g., a photochromic contact lens 200), the contact lens 200 overlying, i.e., contacting, the
With further reference to fig. 6, the wearer maximizes exposure of the
Referring to fig. 4-6, if the contact lens 200 is a photochromic contact lens 200, a first intensity measurement may be taken with the contact lens 200 in place on the
As described above, since the
Where imaging device 400 includes a CCD, some of the measured intensity values may be due in part to dark current on the CCD. The dark current may depend on the temperature on the CCD. The manufacturer of the imaging device 400 may provide a table or graph of intensity values on the CCD due to dark current. The intensity due to dark current at various temperatures can be determined by taking one or more measurements with imaging device 400 while the shutter is closed. The temperature measurement may be performed with a temperature measurement device while measuring the first and second intensity values. The imaging device 400 may include a temperature measurement device or may use an external temperature measurement device.
In the first and second measurements, intensity data may be acquired over a range of wavelengths or for a particular wavelength. In comparing the data of the two measurements, the following formula may be applied:
wherein
TMeasIs the transmission of electromagnetic radiation through the contact lens 200;
IOis a measurement of a first intensity;
ITis a measurement of the second intensity; and
d is the intensity value due to dark current on the intensity measurement device.
Measured absorbance A of the contact lens 200MeasIs defined as
The intensity of the electromagnetic radiation measured in the second measurement passes through the contact lens 200 twice, i.e., once when it travels from the light source 300 through the contact lens 200 to the ocular surface 100 (area 110), and again when it is reflected from the ocular surface 100 (area 110) back through the contact lens 200 to the imaging device 400. To correct for electromagnetic radiation passing twice through the contact lens 200Absorbance A measuredMeasIs divided by a factor of 2 to obtain a corrected absorbance value ACorrOr:
corrected transmission TCorrThe value of (d) is calculated as follows:
the above equation is simplified to:
it should be understood that transmittance and absorbance are closely related values. Thus, any disclosure or teaching herein relating to determining transmittance also relates to determining absorbance, and vice versa, unless the context clearly indicates otherwise.
It should be understood that changes in transmittance and/or absorbance may be determined where an unactivated photochromic or non-photochromic contact lens 200 is positioned to cover the
The intensity of the electromagnetic radiation emitted by the light source 300 may vary over time. For example, when practicing the method of the present invention in an outdoor environment where light source 300 is the sun, the cloud may pass through the sun between the first measurement and the second measurement, thereby affecting the intensity of electromagnetic radiation incident on
A comparison between the measured values of electromagnetic radiation reflected from the auxiliary location 150 between the first measurement and the second measurement may be used to compensate for variations in the intensity of the electromagnetic radiation emitted from the light source 300. For example, if the intensity data acquired from the secondary location 150 indicates a ten percent reduction in the intensity of the electromagnetic radiation emitted from the light source 300 between the first measurement and the second measurement, then the measured transmittance (T) and absorbance (a) are determinedMeas) And corrected absorbance (A)Corr) And corrected transmittance (T)Corr) First intensity (I)O) And/or a second intensity (I)T) May be adjusted by that amount. The adjustment may be applied by a processor implementing software.
Exemplary software that can be used to analyze intensity data includes Igor Pro developed by WaveMetrics; image J developed by National Institutes of Health; LabVIEW developed by National Instruments; origin and OriginPro developed by OriginLab; and Microsoft excel developed by Microsoft corporation. Other software may perform the analysis of the intensity data, as is known in the application field.
In yet another exemplary method, an unactivated contact lens 200 may be placed on
In another exemplary method, the activated contact lens 200 is placed on the
wherein, TYIs the transmittance of the contact lens 200, Y, determined according to the CIE Y valueuncoveredIs the Y value of a portion of the image of the eye table 100 where the eye table 100 is not covered by the contact lens 200, and YcoveredIs the Y value of a portion of the image of the eye table 100 in which the eye table 100 is covered by the contact lens 200. The transmittance using the X value and the Z value may be determined using the same formula using the X value and the X value instead of the Y value, respectively.
FIG. 7 is a block diagram depicting steps of an exemplary method of the present invention.
FIG. 8 is a block diagram depicting steps of another exemplary method of the present invention.
The invention according to the present disclosure may be further illustrated by the following examples. This example does not limit the invention. This example is intended only to suggest a manner of practicing the invention. Those knowledgeable in optics and other professionals may find other ways to practice the present invention. However, those ways should be considered to be within the scope of the present invention.
Example 1
Example 1 relates to measuring transmittance and absorbance of photochromic contact lenses in an outdoor environment.
The contact lenses on the eye surface were measured according to the invention on an outdoor test platform filled with sunlight. The imaging device is an uncalibrated AVT camera with an F-number set to 8 and white balanced. The photochromic contact lenses tested were impregnated with broadband absorbing photochromic dyes and values in the red, green and blue (RGB) planes were still available. The ocular surface is a human eye. The RGB filters are not applied to the lens of the camera. Because the photochromic dye in the subject's glasses absorbs over a broad spectrum, the measurement according to this example is considered to not require an RGB filter. Image data were analyzed using Igor Pro 6.37. Before the measurement, the measured photochromic glasses were activated on the eye for 20 minutes under ambient light. A transmittance value through the photochromic eyewear is determined based on a difference in intensity data between two images taken of the subject's eye. Because the transmittance value is determined based on the light reflected from the eye, the absorbance value is corrected by a factor of 2, as described above. The intensity values are measured in "counts" as units of nominal voltage. Prior to the measurement, dark values in the red, green and blue planes were determined.
The image data also includes the area around the subject's eyes from which intensity data from the auxiliary location can be obtained, as described above. The auxiliary position is located outside the subject's eye. The change in ambient intensity between measurements is considered based on the percentage change in intensity data reflected from the secondary location, and a correction multiplier is determined based on the inverse of this value. The intensity data from the auxiliary location is referred to as a third intensity measurement, which corresponds to the image data from the contact lens acquired at the first intensity measurement, and as a fourth intensity measurement, which corresponds to the image data of the contact lens acquired at the second intensity measurement. The values obtained are shown in table 1 below. "corrected transmittance" is a value that applies a correction multiplier to uncorrected transmittance. The "corrected absorbance" value is obtained from the corrected transmittance value corrected by a factor of 2, as described above.
TABLE 1
The invention also features one or more of the following clauses.
Clause 1. a method for determining the transmittance of electromagnetic radiation through a contact lens 200 in direct contact with an
Clause 2. the method of clause 1, wherein the measuring step is accomplished by an intensity measuring device 400 (preferably, an imaging device).
Clause 3. the method of clause 2, further comprising: determining an intensity value due to dark current on the intensity measurement device 400; and calculating the transmittance of electromagnetic radiation through the contact lens 200 according to the following formula:
wherein T isCorrIs the transmission of electromagnetic radiation through the contact lens 200; i isOIs a measurement of a first intensity; i isTIs a measurement of the second intensity; and d is an intensity value due to dark current on the intensity measurement device 400.Clause 4. the method of any of clauses 1-3, further comprising: measuring a first intensity at a first location of
Clause 5. the method of clause 4, further comprising: measuring a third intensity of radiation reflected from the secondary location 150 simultaneously with the first intensity, wherein the at least one
Clause 6. the method of any of clauses 2 to 5, wherein the intensity measurement device 400 is configured to measure the intensity of the electromagnetic radiation within the spectrum of the electromagnetic radiation including the wavelength ranges of 1nm to 1,000nm, preferably 380-780 nm.
Clause 7. the method of any of clauses 2-6, wherein the intensity measurement device 400 is configured to measure the intensity of electromagnetic radiation within the spectrum of electromagnetic radiation that includes a wavelength range of 460 ± 20 nm.
Clause 8. the method of any of clauses 2-7, wherein the intensity measurement device 400 is configured to measure the intensity of electromagnetic radiation within the spectrum of electromagnetic radiation that includes a wavelength range of 555 ± 20 nm.
Clause 9. the method of any of clauses 2-8, wherein the intensity measurement device 400 is configured to measure the intensity of the electromagnetic radiation within the spectrum of electromagnetic radiation that includes a wavelength range of 635 ± 20 nm.
Clause 10. the method of any one of clauses 1 to 9, wherein the measurements of the first intensity and the second intensity are from a wavelength range selected from the group consisting of 460 ± 20nm, 555 ± 20nm, and 635 ± 20 nm.
Clause 11. the method of any of clauses 2 to 10, further comprising applying a filter 450 on the detector of the intensity measurement device 400 before measuring the first intensity and the second intensity.
Clause 12. the method of clause 11, wherein the filter 450 is centered at a wavelength selected from the group consisting of 460 ± 20nm, 555 ± 20nm, and 635 ± 20 nm.
Clause 13. the method of clause 11 or 12, wherein the filter 450 is a three-wavelength notch filter.
Clause 14. the method of any one of clauses 1-13, wherein the
Clause 15. the method of clause 14, wherein the
Clause 16. the method of clause 15, further comprising measuring a value of the second intensity on the central portion or the peripheral portion of the contact lens 200.
Clause 17. the method of any one of clauses 1-16, wherein the contact lens 200 is a photochromic contact lens 200 or a tinted contact lens 200.
Clause 18. a method for determining the transmittance of a photochromic contact lens 200 at a desired activation level, comprising: selecting a desired wavelength range of electromagnetic radiation; selecting a desired activation level for the photochromic contact lens 200; exposing the photochromic contact lens 200 to actinic radiation until the photochromic contact lens 200 reaches a desired activation level; maximizing visibility of
Clause 19. the method of clause 18, further comprising applying a filter 450 on the imaging device 400 before capturing the first image and the second image.
Clause 20. the method of clause 19, wherein the filter 450 is centered at a wavelength selected from the group consisting of 460 ± 20nm, 555 ± 20nm, and 635 ± 20 nm.
Clause 21. the method of clause 19 or 20, wherein the filter 450 is a three-wavelength notch filter.
Clause 22. a method for determining the transmittance of electromagnetic radiation through a contact lens 200, comprising: positioning an unactivated contact lens 200 on a portion of an
Clause 23. a method for determining the transmittance of electromagnetic radiation through a contact lens 200, comprising: measuring a first intensity of radiation reflected by a
Clause 24. the method of any one of clauses 1-23, wherein the contact lens 200 is in direct contact with the
Clause 25. the method of clause 1, wherein the contact lens 200 is positioned on the
Clause 26. a
Clause 27. the measurement system 10 of clause 26, further comprising an eye table 100.
Clause 28. the measurement system 10 of clause 26 or 27, wherein the light source 300 is a natural light source or an artificial light source.
Clause 29. the measurement system 10 of any of clauses 26 to 28, wherein the intensity measurement device 400 comprises an imaging device.
Clause 30. The measurement system 10 of any of clauses 27 to 29, wherein the intensity measurement device 400 is configured to measure the intensity of radiation within the electromagnetic radiation spectrum comprising the wavelength range of 380-780 nm.
Clause 31. The measurement system 10 of any of clauses 27 to 30, wherein the intensity measurement device 400 is configured to measure the intensity of radiation within the electromagnetic radiation spectrum including a wavelength range of 460 ± 20 nm.
Clause 32. The measurement system 10 of any of clauses 27 to 31, wherein the intensity measurement device 400 is configured to measure the intensity of radiation within the electromagnetic radiation spectrum including a wavelength range of 555 ± 20 nm.
Clause 33. The measurement system 10 of any of clauses 27 to 32, wherein the intensity measurement device 400 is configured to measure the intensity of radiation within an electromagnetic radiation spectrum including a wavelength range of 635 ± 20 nm.
Clause 34. The measurement system 10 of any of clauses 27 to 33, further comprising a filter 450 over the detector of the intensity measurement device 400.
Clause 35. The measurement system 10 of clause 34, wherein the filter 450 is centered at a wavelength selected from the group consisting of 460 ± 20nm, 555 ± 20nm, and 635 ± 20 nm.
Clause 36. The measurement system 10 of clauses 34 or 35, wherein the filter 450 is a three-wavelength notch filter.
Clause 37. The measurement system 10 of any of clauses 27 to 36 wherein the
Clause 38. The method of any of clauses 1-17, wherein the contact lens 200 is a photochromic contact lens 200, preferably a photochromic contact lens, and the method comprises at least partially activating the photochromic contact lens 200 between measuring the first intensity and measuring the second intensity.
Although the disclosure has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred aspects, it is to be understood that such detail is solely for that purpose and that the disclosure is not limited to the disclosed aspects, but is intended to cover modifications and equivalent arrangements. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any aspect can be combined with one or more features of any other aspect.
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