A Focus on the Optical Properties of the Regenerated Newt Lens

Abstract

Lens regeneration studies in the adult newt suggest that molecular aspects of lens regeneration are complete within 5 weeks of lentectomy. However, very little is known about the optical properties of the regenerated lens. In an aquatic environment, the lens accounts for almost all of the refractive power of the eye, and thus, a fully functional lens is critical. We compared the optical properties of 9- and 26-week regenerated lenses in the red spotted newt, Notophthalmus viridescens, with the original lenses removed from the same eyes. At 9 weeks, the regenerated lenses are smaller than the original lenses and are histologically immature, with a lower density of lens proteins. The 9 week lenses have greater light transmission, but significantly reduced focal length and refractive index than the original lenses. This suggests that following 9 weeks of regeneration, the lenses have not recovered the functionality of the original lens. By 26 weeks, the transmission of light in the more mature lens is reduced, but the optical parameters of the lens have recovered enough to allow functional vision.

In Vivo Imaging of Newt Lens Regeneration: Novel Insights Into the Regeneration Process

“…Our current understanding of the cellular mechanisms during lens regeneration in newts mainly comes from studies employing acquisition techniques such as transmission and scanning electron microscopy, light microscopy with hematoxylin-eosin (H&E) staining and in situ hybridization, transmission scatter measuring system analysis, and immunofluorescence. [8][9][10][11][12][13][14][15] Although the use of these technologies has expanded our understanding of the process of newt lens regeneration in the past decades, these are all ex vivo imaging technologies, and most of them require extensive tissue processing. These technologies can only assess morphological or cellular changes at a fixed point in time.…”