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Peripheral Defocus of the Monkey Crystalline Lens With Accommodation in a Lens Stretcher.

Research paper by Bianca B Maceo Heilman, Fabrice F Manns, Marco M Ruggeri, Arthur A Ho, Alex A Gonzalez, Cor C Rowaan, Andres A Bernal, Esdras E Arrieta, Jean-Marie JM Parel

Indexed on: 26 May '18Published on: 26 May '18Published in: Investigative ophthalmology & visual science



Abstract

To characterize the peripheral defocus of the monkey crystalline lens and its changes with accommodation. Experiments were performed on 15 lenses from 11 cynomolgus monkey eyes (age: 3.8-12.4 years, postmortem time: 33.5 ± 15.3 hours). The tissue was mounted in a motorized lens stretcher to allow for measurements of the lens in the accommodated (unstretched) and unaccommodated (stretched) states. A custom-built combined laser ray tracing and optical coherence tomography system was used to measure the paraxial on-axis and off-axis lens power for delivery angles ranging from -20° to +20° (in air). For each delivery angle, peripheral defocus was quantified as the difference between paraxial off-axis and on-axis power. The peripheral defocus of the lens was compared in the unstretched and stretched states. On average, the paraxial on-axis lens power was 52.0 ± 3.4 D in the unstretched state and 32.5 ± 5.1 D in the stretched state. In both states, the lens power increased with increasing delivery angle. From 0° to +20°, the relative peripheral lens power increased by 10.7 ± 1.4 D in the unstretched state and 7.5 ± 1.6 D in the stretched state. The change in field curvature with accommodation was statistically significant (P < 0.001), indicating that the unstretched (accommodated) lens has greater curvature or relative peripheral power. The cynomolgus monkey lens has significant accommodation-dependent curvature of field, which suggests that the lens asserts a significant contribution to the peripheral optical performance of the eye that also varies with the state of accommodation.