We performed measurements to validate damage threshold trends in minimum visible lesion (MVL) studies as a function of spot size for nanosecond laser pulses. At threshold levels, nanosecond pulses produce microcavitation bubbles that expand and collapse around individual melanosomes. This microcavitation process damages the membranes of retinal pigment epithelium (RPE) cells. A spot size study on retinal explants 1 found cell damage fluence (energy/area) thresholds were independent of spot size when microcavitation caused the damage, contradicting past in vivo retinal spot size experiments. 2 3 4 The explant study (ex vivo) used a top-hat beam profile, whereas the in vivo studies used Gaussian beams. The difference in spot size trends for damage in vivo versus ex vivo may be attributed to the optics of the eye but this has not been validated. In this study, we exposed artificially pigmented human RPE cells (hTERT-RPE1)-in vitro-to 7 ns pulsed irradiation from a Ti:Sa TSA-02 regenerative amplifier (1055 nm) with beam diameters of 44, 86, and 273 µm (Gaussian beam profiles). We detected the microcavitation event with strobe illumination and time-resolved imaging. We used the fluorescent indicator dye calcein-AM, with excitation by an Argon laser (488 nm), to assess cell damage. Our current results follow trends found in the in vivo studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.