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F. Manns, D.B. Denham, A.C. Acosta, C. Billotte, A. Abri, N. Ziebarth, M. Orozco, A. Ho, J.–M. Parel; Optomechanical Characteristics of Post–Mortem Rhesus Monkey Lenses During Simulation of Accommodation: Effect of Age . Invest. Ophthalmol. Vis. Sci. 2005;46(13):730.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To characterize the age–dependence of the force–stretch and force–power relation in postmortem rhesus monkey lenses during accommodation simulation. Methods: Rhesus eyes (n=20, age: 0.5 to 8.9 years, postmortem time <30 hours) were dissected to produce tissue specimens containing the lens, zonules and ciliary body, with the surrounding sclera bonded to 8 separate PMMA segments. The sclera was cut between the segments and the specimen was mounted in a system that simulates lens accommodation by radial stretching (Parel et al, ARVO 2002). The tissues were stretched 2mm in 0.25mm steps. Load (g), lens power (D), and lens diameter (mm) were recorded at each step and analyzed as a function of age. Results: The power–load and diameter–load responses were linear when lens stretch was less than 5%, with average slopes of –2.6+/–0.9 D/g and 1.0+/–0.4%/g, respectively. There was no statistically significant change in power–load slopes with age. The stretch–load slope increased slightly with age (0.006%/g/month), but the increase was not statistically significant. When stretching produced more than 5% diameter increase (n=7), the power–load curves followed an exponential decay with an asymptote corresponding to the maximum possible change in power. In the unstretched state (accommodated), there was a significant decrease in power and a significant increase in lens diameter with age. Conclusions:In post–mortem rhesus monkey lenses (0.5 to 8.9 years) there are no statistically significant changes in the optomechanical response of the lens that could explain the loss of accommodation with age. The results indicate that rhesus lenses progressively take on an unaccommodated shape. This change may contribute to presbyopia by limiting the change in lens shape that can be achieved during accommodation. Support: NIH EY14225; Florida Lions Eye Bank; Australian Government’s CRC scheme; NIH center grant P30–EY014801; Research to Prevent Blindness.; Henri and Flore Lesieur Foundation; Norma Kenyon PhD; Pat Gullett DVM and Daniel Rothen, DVM.
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