When sunlight strikes the lens of our eyes, some of the energy absorbed is converted into heat. But some of that “absorbed energy” is also converted into light. It’s a blue-green “glow” that is responsible for much of the visual discomfort that we call glare. However, later in life, our lens emits a new, red light “glow” (fluorescence) that may repair the retina. A U.S. patent was recently issued to Photoprotective Technologies, Inc. that mimics the details of the red fluorescence of the human lens.

In the seventh decade of life, the human lens takes on a red glow (fluorescence) that may repair the retina by effectuating photobiomodulation, a type of therapy that improves the function of the cells of human tissue and organs of the body when exposed to the red and near infrared wavelengths of sunlight. Dr. Jim Gallas, physicist and CEO of Photoprotective Technologies (PPT), located in San Antonio, Texas, has been awarded U.S. Patent 11,672,703B2—assigned to PPT—that mimics the details of the red fluorescence spectrum of the human lens. The immediate application is for sunglasses but can include many other light filters, according to PPT.

In the late 1980’s, PPT pioneered the patents and technologies to incorporate melanin into ophthalmic lenses. In the late 1990s, the company was assigned a patent for ocular lens pigment (OLP), an amber-tinted pigment that provides photoprotection to the retina. However, the concentration of the OLP in our lens continues to increase with age, causing the human lens to progressively darken – posing a serious dilemma. “An un-checked darkening of the ocular lens with age is not sustainable, so the visual system appears to pivot from photoprotection to photobiomodulation (PBM) – actual repair,” said Gallas.




The red fluorescence from the human lens. Mimicking Nature - using fluorescence-based photobiomodulation (FPBM): In early life, a layer of melanin (black) forms in the back of the eye behind the retina – to reduce damage to the retina, and to reduce glare; later in mid-life, the lens takes on an amber color that reduces UV and high energy visible (HEV) light - to protect the retina. In the seventh decade of life the lens takes on a far red and near infrared fluorescence that may repair the retina (photobiomodulation).
  



Dr. Jim Gallas, physicist and CEO of Photoprotective Technologies



The significance of the patent is that the sudden appearance of the red fluorescence in our lens—late in life—may give us new insights into the histological progression of our visual system. But the details of the red fluorescence may also provide a technology paradigm for PPT for sunglass lenses that benefit from many years of evolution in the field of photobiomodulation where specific physical parameters (like the intensities and specific wavelengths of the red and near infrared light are critical for positive PBM outcomes. While the widely-supported mechanism for the action of photobiomodulation involves the absorption of red and near IR light by cytochrome-C between 600 nm and 1000 nm, scientists have found that exposure of the retina to the specific wavelength of 670 nm—using mostly LED lights—has produced the most positive PBM outcomes. “Notably, the red fluorophore of the human lens has a maximum fluorescence intensity at 670 nm,” Gallas noted.



Photoprotective Technologies, Inc. has established itself worldwide as a leader in blue-light filtration. Through research and numerous patents in melanin light filtration technology, the company has made an impressive impact on the development of sunglass lenses that protect and enhance vision through blue-light filtration with melanin. For over thirty years, it has continued to lead the vision industry by developing technologies and patents for melanin and melanin-like pigments that offer natural protection to the skin and eyes.



Since 1989, Photoprotective Technologies, Inc. has developed the patents and technologies to synthesize and chemically modify melanin so that it can be incorporated into various skin care products and optical quality plastic lenses.





The red fluorophore of the human lens (RFHL) may broaden the scope of the melanin paradigm for vision protection to now include vision repair: both occur as endogenous pigments of the visual system – melanin for photoprotection; and RFHL for photobiomodulation. Both benefit from millennia of evolution and therefore serve PPT as a paradigm for developing what Gallas calls a “Comprehensive Vision Technology.”

So, how does this new technology work? While many sunglass lenses provide protection to our vision, they also universally convert the absorbed sunlight energy into heat. The new sun lenses developed by PPT use fluorescent dyes to absorb the harmful HEV light and then re-emit the energy as fluorescent light at the red and near infrared wavelengths previously associated with repair (photobiomodulation) of the retina. This repair includes, for example, restoration of visual acuity for subjects with macular degeneration and will also provide PBM light to the sensitive skin around the eyes. These wavelengths span the range from 600 nm to around 1000 nm, as described in the first PPT patent to issue on red light repair (U.S. Pat. 15/638,361). “The unique feature of the current patent is that it is a product developed by nature,” explained Gallas. PPT has multiple patents pending that relate to fluorescence-based photobiomodulation with allowed claims for other applications that include skincare lotions.