Avaliação da eficácia dos filtros de luz azul na proteção de retinas expostas ao diodo emissor de luz de alta potência: um estudo in vivo

Abstract

Objective: To evaluate the the effectiveness of the blue light filter in protecting the retinas of Wistar rats exposed to the blue light emitted by a high-power LED light curing device. Materials and methods: Nine Wistar rats were used in the research, and their ocular structures were the subjects of study. The animals were divided into three groups (n = 6 ocular structures each): GEI - indirect exposure without protection filter; GEP - exposure over the protection filter of the VALO® curing and GC – control group (without exposure), total of 18 eye oculares. During the photostimulation of each animal, the eye considered experimental was exposed to the indirect light of the highintensity LED at 3200mW/cm² (Valo® Ortho - Ultradent) for 144 seconds at 30cm. The animals were exposed to the LED light three times a day to investigate if any acute inflammatory changes occurred in the retina. Seven days after the photostimulation sessions, the animals were anesthetized and euthanized. Subsequently, the eyes were dissected and histologically processed. The histological slides were analyzed stereologically and histomorphometrically to measure the investigated retinal parameters. Results: There was 50% increase in the total volume of the retina in the GEI due to the increased volume of ganglion cell layers (GCL), inner plexiform layers (IPL), outer nuclear layers (ONL), and the extensions of rods and cones. There was no statistically significant difference in terms of density. However, there was an average increase of 15% in the nuclear area of cells in all studied layers in the CNE and 49,30 % in the CCG in the GEI. Conclusion: Exposure to LED light emitted by a dental curing device causes damage to the animal retina structure, and the use of a protective filter can prevent damage caused by exposure.