Retinal light toxicity

Abstract

The ability of light to enact damage on the neurosensory retina and underlying structures has been well understood for hundreds of years. While the eye has adapted several mechanisms to protect itself from such damage, certain exposures to light can still result in temporal or permanent damage. Both clinical observations and laboratory studies have enabled us to understand the various ways by which the eye can protect itself from such damage. Light or electromagnetic radiation can result in damage through photothermal, photomechanical, and photochemical mechanisms. The following review seeks to describe these various processes of injury and many of the variables, which can mitigate these modes of injury.

Induction of the Unfolded Protein Response by Constitutive G-protein Signaling in Rod Photoreceptor Cells

“…Excessive light exposure in itself is damaging to the retina (5,6), and different experimental paradigms of light damage have been used to investigate the mechanism of photoreceptor cell apoptosis. The use of rhodopsin knock-out and RPE65-deficient mice clearly showed the requirement of rhodopsin and a functioning visual cycle in light damage (7).…”

Exposure-Limit Distance as a Safety-Indicating Parameter of a High-Intensity Flash Source

“…[1][2][3] 강한 빛을 가까운 거리에서 보게 되는 경우 에는 매우 큰 광량이 일시적으로 망막의 영상면에 집속되어 시력에 영향을 미칠 수 있으며 더욱이 눈의 동공의 직경이 낮에는 2 mm에서 캄캄하게 어두운 밤에는 8 mm까지 커지 는 것을 [4,5] 고려하면 야간에 사용되는 고섬광을 가까운 거리 에서 바라보게 되는 상황은 시력에 매우 심각한 영향을 미칠 수 있다. [4][5][6] [2,3] , 개략적으로라도 섬광 의 적외선 발광 특성도 측정할 수 있었다. [6,7] 또한 최근의 연 구에서 섬광의 발광 특성, 섬광에 노출되는 거리, 그리고 주 변 환경의 조도에 따른 망막에 도달되는 복사조도(irradiance) 와 총 입사에너지를 모델링하였다.…”

Toward biomaterial-based implantable photonic devices

“…This could occur if high optical powers are used, for example, to compensate for optical loss in the system, light is focused accidentally to a small area, or if phototoxic ultraviolet (UV) light is needed to form the device, such as UV-cross-linking of in situ forming hydrogels [40]. The primary mechanisms of light damage to cells are photothermal and photochemical [77,78]. Photothermal damage occurs due to light absorption leading to an increase in temperature which can cause denaturation of deoxyribonucleic acid (DNA) and proteins above 67°C [78].…”

“…Importantly, the photothermal damage threshold increases for longer exposure time because heat dissipates over time and space. Photochemical damage is mediated by cellular chromophores that cause the generation of free radicals that cause cellular injury [77]. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) provides guidelines on acceptable limits of exposure to laser radiation, depending on wavelength and duration [79].…”