Filter and a method for determining a filter taking into account the spectral transmittance of an ocular media of an eye of a wearer

1 . A method for determining at least one filter for a visual equipment intended to be placed in front of the eye of a user, said at least one filter being able to improve visual comfort and/or visual performance of said user, the method comprising the following steps:

determining a spectral transmittance of an ocular media of at least one eye of said user, based on a measurement on said user or based on the age of said user;

determining a target transmittance value for at least one filter corresponding to a filtering function of said at least one filter;

determining said at least one filter based on the determined spectral transmittance of the ocular media of said user, said at least one filter having a spectral transmittance computed as follows:

T (λ,age)= T Ref(λ)/ T crystalline(λ,age)for

T Ref(λ)/ T crystalline(λ,age)<1,

and

T (λ,age)=1for T Ref(λ)/ T crystalline(λ,age)>1

wherein TRef(λ)=Tlens(λ)*TcrystallineXyearsold(λ),

with Tlens(λ) the target transmittance value of the filter,

TcrystallineXyearsold(λ) is the spectral transmittance of the ocular media of the user of X years old,

TRef(λ) which is the spectral transmittance of the filter,

λ is the wavelength, and

such that said filter has a spectral transmittance profile comprising:

a first portion having a maximum transmittance value between 380 nm and a predetermined wavelength threshold, said predetermined wavelength threshold is between 425 and 525 nm,

a second portion with a decreasing transmittance value between said predetermined wavelength threshold and 670 nm, said second portion continuously decreasing from said maximum transmittance value to a minimum transmittance value, said minimum transmittance value corresponding to a wavelength between 630 nm and 670 nm, said minimum transmittance value is between −10% and +10% of said target transmittance value; and

incorporating the at least one filter into the visual equipment intended to be placed in front of the eye of the user.

2 . The method according to claim 1 , wherein said maximum transmittance value is between 70 and 100%.

3 . The method according to claim 2 , wherein the spectral transmittance of the ocular media of said user is determined based on a measurement on said user.

4 . The method according to claim 2 , wherein the spectral transmittance of the ocular media of said user is determined based on the age of said user.

5 . The method according to claim 1 , wherein the spectral transmittance of the ocular media of said user is determined based on a measurement on said user.

6 . The method according to claim 1 , wherein the spectral transmittance of the ocular media of said user is determined based on the age of said user.

7 . The method according to claim 1 , wherein the spectral transmittance of the ocular media of said user is determined based on a spectral transmission test.

8 . The method according to claim 7 , wherein the spectral transmission test comprises a step of measurement of an absolute scotopic threshold.

9 . The method according to claim 7 , wherein the spectral transmission test comprises a step of measurement of an absolute light discomfort.

10 . The method according to claim 7 , wherein the spectral transmission test comprises a step of equalizing the photopic luminance.

11 . The method according to claim 1 , wherein the ocular media of said user is the crystalline lens.

12 . The method according to claim 1 , wherein a spectral transmittance of the filter is computed as follows:

T (λ,age)= T Ref (λ)/ T crystalline(λ,age)

with T ( A ,age)=1for T Ref(λ)/ T crystalline(λ,age)>1.

13 . A filter for a visual equipment intended to be placed in front of the eye of a user, wherein a spectral transmittance of the filter is calculated based on a spectral transmittance of an ocular media of said user, said filter having a spectral transmittance computed as follows:

T (λ,age)= T Ref(λ)/ T crystalline(λ,age)for

T Ref(λ)/ T crystalline(λ,age)<1,

and

T (λ,age)=1for T Ref(λ)/ T crystalline(λ,age)>1

wherein TRef(λ)=Tlens(λ)*TcrystallineXyearsold(λ), with Tlens(λ) the target transmittance value of the filter,

TcrystallineXyearsold(λ) is the spectral transmittance of the ocular media of the user of X years old,

TRef(λ) which is the spectral transmittance of the filter,

λ is the wavelength, and

such that said filter has a spectral transmittance profile comprising:

a first portion having a maximum transmittance value between 380 nm and a predetermined wavelength threshold, said predetermined wavelength threshold is between 425 and 525 nm,

a second portion with a decreasing transmittance value between said predetermined wavelength threshold and 670 nm, said second portion continuously decreasing from said maximum transmittance value to a minimum transmittance value, said minimum transmittance value corresponding to a wavelength between 630 nm and 670 nm, said minimum transmittance value is between-10% and +10% of said target transmittance value.

14 . A set of filters for a visual equipment intended to be placed in from of the eye of a user, wherein each filter in the set has a spectral transmittance based on a spectral transmittance of an ocular media f users having different ages, the spectral transmittance of each filter of said set of filters being calculated such that each filter of the set of filters has a spectral transmittance computed as follows:

T (λ,age)= T Ref(λ)/ T crystalline(λ,age)for

T Ref(λ)/ T crystalline(λ,age)<1,

and

T (λ,age)=1for T Ref(λ)/ T crystalline(λ,age)>1

wherein TRef(λ)=Tlens(λ)*TcrystallineXyearsold(λ), with Tlens(λ) the target transmittance value of the filter,

TcrystallineXyearsold(λ) is the spectral transmittance of the ocular media of the user of X years old,

TRef(λ) which is the spectral transmittance of the filter,

λ is the wavelength, and

said filter has a spectral transmittance profile comprising:

a first portion having a maximum transmittance value between 380 nm and a predetermined wavelength threshold, said predetermined wavelength threshold is between 425 and 525 nm,

a second portion with a decreasing transmittance value between said predetermined wavelength threshold and 670 nm, said second portion continuously decreasing from said maximum transmittance value to a minimum transmittance value, said minimum transmittance value corresponding to a wavelength between 630 nm and 670 nm, said minimum transmittance value is between −10% and +10% of said target transmittance value.