Homogeneous light stimulation of melanopsin and cones with a Maxwellian view device for the human eye

Abstract

We designed and tested a device to stimulate specifically one photoreceptor type, or a combination of some of them, of the human eye by using up to six primaries. The device produces a homogeneous light field over 40 • which is projected onto the retina through a Maxwellian view optical system. It avoids the use of an artificial pupil, does not need pupil dilation and retinal illumination can be easily controlled. We successfully tested it with four primaries for melanopsin and S-cone stimulation while maintaining other photoreceptors at a fixed level in photopic regime.

A simple Maxwellian optical system to investigate the photoreceptors contribution to pupillary light reflex

“…Indeed, for the stimulation of one class of photoreceptors, the colors pair should be selected in order to give the maximum stimulation contrast to them when alternated. 11,13 The contrast can be computed according to two different definitions, i.e. the Michelson Contrast (C M ) and the Weber Contrast (C W ), calculated as follows:…”

Silent stimulation of cones: a comparison between the ERG and PLR responses

“…21 Therefore, when a pair of colors or two different light distributions E A,λ (λ) and E B,λ (λ) is considered, each photo-sensitive cell is stimulated with of a determined amount or contrast when these colors are alternated. 19,22 In this case, the commonly used Michelson Contrast (C M ), can be computed as follows:…”

Compact High-Resolution Multi-Wavelength LED Light Source for Eye Stimulation

“…Among all, light intensity resolution is one of the most significative limitations, typically being in the range of 10 bits (±0.1%), while the vision science field requires much more precision as the diverse range of the human visual system extends from 10 −6 to 10 8 cd/m 2 [14]. These aspects usually render commercially available options inaccessible to a broader spectrum of small research and medical laboratories, forcing scientists to build their own stimulators [2,[15][16][17]. Furthermore, many of these systems are characterized by a lack of possibility of customization, operating as a sort of black boxes that hinder users from tailoring the configuration and stimulation parameters to specific requirements.…”