Professors Sei-ichi Tsujimura from Nagoya City University and Su-Ling Yeh from National Taiwan University and Kagoshima University have made a groundbreaking discovery regarding our visual acuity (contrast sensitivity). They found that using a light with a specific spectrum capable of selectively stimulating melanopsin cells in the retina can enhance contrast sensitivity.
The research has been published in the journal Vision Research.
Until recently, it was believed that human vision relied solely on cone and rod photoreceptor cells in the retina to identify colors and perceive objects in bright and dark environments, respectively. However, around the year 2000, the discovery of melanopsin ganglion cells (ipRGCs) in the retina shed new light on our understanding of vision.
Melanopsin cells were found to play a significant role in various functions, such as regulating circadian rhythm, influencing pupillary light reflex, brightness perception, and even mood. Understanding the function of melanopsin cells has become a crucial area of research for many scholars.
Professor Tsujimura's team has developed an experimental device that, for the first time globally, can specifically stimulate melanopsin cells by adjusting the light's color spectrum. They conducted experiments to investigate the contribution of melanopsin cells to contrast sensitivity. Contrast sensitivity refers to the ability to distinguish between different shades of brightness in text and images and is a vital aspect of our vision.
The researchers discovered that by increasing the stimulation to melanopsin cells without altering the brightness or chromaticity of the illumination light, contrast sensitivity in humans is enhanced. This finding opens the door to potential developments in innovative lighting systems and displays that go beyond merely altering color or light intensity.
As Professor Tsujimura and his collaborators continue their investigations into human vision, they aim to propose optimal light environments by unraveling the mechanisms within the brain. This exciting discovery offers promising possibilities for advancing our understanding of vision and its applications in various fields.
Sung-En Chien et al, Enhanced human contrast sensitivity with increased stimulation of melanopsin in intrinsically photosensitive retinal ganglion cells, Vision Research (2023). DOI: 10.1016/j.visres.2023.108271