Limits...
A focus on the optical properties of the regenerated newt lens.

Wassmer S, Beddaoui M, Rajai P, Munger R, Tsilfidis C - PLoS ONE (2013)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Ottawa Hospital Research Institute, Vision Research Program, Ottawa, Ontario, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.

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.

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Schematic of newt eye (drawn to proportion from Litzinger and Del Rio Tsonis[23]). The original (pre-operative) lens is shown on the bottom. Based on ocular anatomy, a predicted focal length of 1.32 would ensure a clear image is focused on the retina. The 9-week regenerated lens, with its smaller diameter and shorter focal length of 1.05 mm would focus the image in front of the retina, resulting in a blurred image. The focal distance would have to be 1.47 in the smaller diameter lens in order to have proper functionality.
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pone-0070845-g003: Schematic of newt eye (drawn to proportion from Litzinger and Del Rio Tsonis[23]). The original (pre-operative) lens is shown on the bottom. Based on ocular anatomy, a predicted focal length of 1.32 would ensure a clear image is focused on the retina. The 9-week regenerated lens, with its smaller diameter and shorter focal length of 1.05 mm would focus the image in front of the retina, resulting in a blurred image. The focal distance would have to be 1.47 in the smaller diameter lens in order to have proper functionality.

Mentions: Histologically, the 9-week regenerated lenses were less dense than their original counterparts, and did not have well developed nuclei and cortical structures (Figure 2). This, combined with the reduced size, reduced focal length, and reduced index of refraction suggest that after 9 weeks, the regenerated lens had not yet recovered the functionality of the original lens. The 9 week lens would focus the image in front of the retina, resulting in a blurred image (Figure 3).


A focus on the optical properties of the regenerated newt lens.

Wassmer S, Beddaoui M, Rajai P, Munger R, Tsilfidis C - PLoS ONE (2013)

Schematic of newt eye (drawn to proportion from Litzinger and Del Rio Tsonis[23]). The original (pre-operative) lens is shown on the bottom. Based on ocular anatomy, a predicted focal length of 1.32 would ensure a clear image is focused on the retina. The 9-week regenerated lens, with its smaller diameter and shorter focal length of 1.05 mm would focus the image in front of the retina, resulting in a blurred image. The focal distance would have to be 1.47 in the smaller diameter lens in order to have proper functionality.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3750027&req=5

pone-0070845-g003: Schematic of newt eye (drawn to proportion from Litzinger and Del Rio Tsonis[23]). The original (pre-operative) lens is shown on the bottom. Based on ocular anatomy, a predicted focal length of 1.32 would ensure a clear image is focused on the retina. The 9-week regenerated lens, with its smaller diameter and shorter focal length of 1.05 mm would focus the image in front of the retina, resulting in a blurred image. The focal distance would have to be 1.47 in the smaller diameter lens in order to have proper functionality.
Mentions: Histologically, the 9-week regenerated lenses were less dense than their original counterparts, and did not have well developed nuclei and cortical structures (Figure 2). This, combined with the reduced size, reduced focal length, and reduced index of refraction suggest that after 9 weeks, the regenerated lens had not yet recovered the functionality of the original lens. The 9 week lens would focus the image in front of the retina, resulting in a blurred image (Figure 3).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Ottawa Hospital Research Institute, Vision Research Program, Ottawa, Ontario, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.

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.

Show MeSH
Related in: MedlinePlus