Structural and Functional Change in Albino Rat Retina Induced by Various Visible Light Wavelengths.

Sachiko Kaidzu,Masaki Tanito,Tsutomu Okuno,Akihiro Ohira

doi:10.3390/ijms23010309

Sachiko Kaidzu, Masaki Tanito + Show 2 more

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https://doi.org/10.3390/ijms23010309

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Abstract

The effects of visible light, from short to long wavelengths, on the retina were investigated functionally and histologically. The left eyes of Sprague–Dawley albino rats (6-weeks old, n = 6 for each wavelength) were exposed to seven narrow-band wavelengths (central wavelengths, 421, 441, 459, 501, 541, 581, and 615 nm) with bandwidths of 16 to 29 nm (half bandwidth, ±8–14.5 nm) using a xenon lamp source with bandpass filters at the retinal radiant exposures of 340 and 680 J/cm2. The right unexposed eyes served as controls. Seven days after exposure, flash electroretinograms (ERGs) were recorded, and the outer nuclear layer (ONL) thickness was measured. Compared to the unexposed eyes, significant reductions in the a- and b-wave ERG amplitudes were seen in eyes exposed to 460-nm or shorter wavelengths of light. The ONL thickness near the optic nerve head also tended to decrease with exposure to shorter wavelengths. The decreased ERG amplitudes and ONL thicknesses were most prominent in eyes exposed to 420-nm light at both radiant exposures. When the wavelengths were the same, the higher the amount of radiant exposure and the stronger the damage. Compared to the unexposed eyes, the a- and b-waves did not decrease significantly in eyes exposed to 500-nm or longer wavelength light. The results indicate that the retinal damage induced by visible light observed in albino rats depends on the wavelength and energy level of the exposed light.

Highlights

Received: 15 November 2021Light is largely classified according to its wavelength: ultraviolet (UV) light has a wavelength of 400 nm or less, visible light has a wavelength of 400 to 750 nm, and infrared light has a wavelength of 750 nm or more
We compared the unexposed right eye (Exposure−/Anesthesia+) with the normal control right eye (Exposure−/Anesthesia−) to confirm if it was affected by the exposure and anesthesia
Since there was no significant difference between the a- and b-wave compared to the normal control (Figure 1a,b), the amplitude of the unexposed eye was set at 100% and compared to the amplitude of the exposed eye

Summary

Introduction

Received: 15 November 2021Light is largely classified according to its wavelength: ultraviolet (UV) light has a wavelength of 400 nm or less, visible light has a wavelength of 400 to 750 nm, and infrared light has a wavelength of 750 nm or more. The first report was by Noell et al [1], who found visible light-damaged photoreceptor cells and that light damage can be classified into two types: class I (damage induced by low-intensity light exposure for long durations) and class II (damage induced by relatively high-intensity light exposure for short periods). Regarding the latter, the retinal damage increases in response to shorter wavelengths—that is, the highphoton-energy portion of the visible spectrum (400–500 nm). With the widespread use of tablets and smartphones, it has been suggested that the blue light from these electronic devices using light-emitting diodes (LEDs) may cause blue-light hazard [7]

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