Direct Discrimination of Quantum States by the Human Eye

Age-related macular degeneration (AMD), is a debilitating eye disease that causes a loss of central vision. The prevalence of AMD increases exponentially with age and causes a significant impact through both medical expenses and the social and economic costs associated with vision loss. AMD is the global leading cause of blindness among people over the age of 60. Detection of this eye disease at early stages coupled with prompt treatment can prevent vision loss; however, modern diagnosis methods are ineffective at diagnosis of AMD before vision loss occurs. While a range of available treatment options has been effective at slowing vision loss due to AMD, no treatment exists which can recover lost vision. The investigators propose to apply tools developed in quantum information science to diagnose AMD before vision has been affected, drastically improving health outcomes for patients with AMD.

There has been tremendous progress in generating and detecting structured light which possesses advantageous propagation characteristics such as quantized orbital angular momentum (OAM), non-diffraction, and self-healing. These special beams have found applications in microscopy, encoding and multiplexing of communications, and manipulation of matter. Here the investigators bring the structured light toolbox to vision sciences for the first time and expand the space of possible stimuli. A healthy macula possesses azimuthally ordered dichroic fibres that act as a radial polarization filter, enabling a typical person to perceive linearly polarized light through the entoptic phenomena known as Haidinger's brushes. Despite significant interest in the application of this phenomenon to the detection of age-related macular degeneration, no device has currently seen widespread adoption in a clinical environment. This is due to the difficulty in observing Haidinger's brush, the imprecise measurements that this test can extract, and the difficulty in instructing patients during these tests. Leveraging the quantum-inspired toolbox developed in the field of structured light, the investigators can project polarization-coupled OAM states of light directly on a person's retina. This enables the investigators to create arbitrary entoptic patterns in a person's vision based on the structure and chemical composition of their subjective macula, and the investigators have the opportunity to develop a litany of novel diagnostic tests to characterize and quantify the health of the macula.