Photochromic ophthalmic lens

Abstract

A photochromic ophthalmic lens comprising a photochromic substrate and a filter comprising one or a plurality of layers formed on the main front face of the ophthalmic lens, characterised in that the filter has a total thickness less than or equal to 700 nm and in that the filter provides the main front face with the following properties: an average UVA reflection factor over a range of wavelengths from 330 nanometres to 380 nanometres that is less than or equal to 40%, for an incident angle of between 0° and 15°, an average blue reflection factor over a range of wavelengths from 420 nanometres to 450 nanometres that is greater than or equal to 5%, for an incident angle of between 0° and15°, a spectral reflectivity curve for an incident angle of between 0° and 15°, said reflectivity curve having a reflectivity maximum at a wavelength less than 435 nanometres, and a width at mid-height greater than or equal to 70 nanometres, and for an incident angle of between 0° and 15°, a parameter Δspectra| = 1 - [ R0°-15°-(480 nm) / R0°-15°-(435 nm) ], such that this parameter Δspectra| is greater than or equal to 0.8, in which R0°-15°-(480 nm) represents the reflectivity value of the main front face at 480 nanometres at the incidence in question, and R0°-15°(435 nm) the reflectivity value of the main front face at 435 nanometres at the incidence in question.

Description

technical field [0001] The present invention relates to the field of ophthalmic optics. [0002] More precisely, the invention relates to an ophthalmic lens comprising a photochromic substrate, and the front main face of which photochromic substrate comprises an optical filter intended to reduce the impact of blue light on the retina of the spectacle wearer. phototoxic effects without reducing the photochromic properties of ophthalmic lenses. Background technique [0003] Throughout this patent application, reference will be made to ranges of values, in particular ranges of wavelengths and angles of incidence. The expression "comprised between the value x and the value y" is understood to mean "in the range from x to y", the limits x and y being included in this range. [0004] Light visible to the human eye extends over a spectrum extending in wavelength from 380 nanometers (nm) to 780 nm or thereabouts. That part of the spectrum lying between about 380nm and 500nm corre...

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