The objective of the proposed collaborative program is to understand the relationship between the optical and mechanical properties of the crystalline lens and the amplitude of accommodation and its loss in presbyopia. The general application of these bioengineering studies is the development of suitable technology including devices and surgical procedures for the restoration of near vision to presbyopes, as well as the restoration of good visual performance to cataract patients.
The specific aims of the proposed research are: 1. To measure the mechanical properties of the crystalline lens 2: To measure the mechanical properties of the lens capsule 3: To measure the mechanical properties of the zonules 4: To develop mechanical and optical instrumentation to simulate accommodation in explanted crystalline lenses of eye-bank eyes (lens stretcher) 5: To quantify changes in normal and refilled crystalline lens during simulated accommodation 6: To develop an opto-mechanical model of the lens during accommodation The static and dynamic lens mechanical properties will be measured as a function of age using a micro-Fourier rheometer. The mechanical properties of the capsule will be measured using a custom-made capsule stretching device. The mechanical properties of the zonules will be investigated using atomic force microscopy and tensiometry. An opto-mechanical lens stretching system will be constructed to simulate accommodation on human cadaver lens specimens that include the crystalline lens, lens capsule, zonules, ciliary body and sclera. The system will be used to measure and correlate stretching forces with changes in lens equatorial diameter, thickness, displacement, topography, power and aberrations during simulated accommodation as a function of age. The contribution of the lens capsule and zonules to the mechanics of accommodation will be quantified by conducting lens stretching experiments before and after lens refilling with injectable materials of controlled mechanical properties.
| Chang, Yu-Cherng; Liu, Keke; Cabot, Florence et al. (2018) Variability of manual ciliary muscle segmentation in optical coherence tomography images. Biomed Opt Express 9:791-800 |
| Chang, Yu-Cherng; Liu, Keke; de Freitas, Carolina et al. (2017) Assessment of eye length changes in accommodation using dynamic extended-depth OCT. Biomed Opt Express 8:2709-2719 |
| Augusteyn, Robert C; Maceo Heilman, Bianca; Ho, Arthur et al. (2016) Nonhuman Primate Ocular Biometry. Invest Ophthalmol Vis Sci 57:105-14 |
| Ruggeri, Marco; de Freitas, Carolina; Williams, Siobhan et al. (2016) Quantification of the ciliary muscle and crystalline lens interaction during accommodation with synchronous OCT imaging. Biomed Opt Express 7:1351-64 |
| Marussich, Lauren; Manns, Fabrice; Nankivil, Derek et al. (2015) Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher. Invest Ophthalmol Vis Sci 56:4239-48 |
| Neri, Alberto; Ruggeri, Marco; Protti, Alessandra et al. (2015) Dynamic imaging of accommodation by swept-source anterior segment optical coherence tomography. J Cataract Refract Surg 41:501-10 |
| Wu, Chen; Han, Zhaolong; Wang, Shang et al. (2015) Assessing age-related changes in the biomechanical properties of rabbit lens using a coaligned ultrasound and optical coherence elastography system. Invest Ophthalmol Vis Sci 56:1292-300 |
| Pour, Hooman Mohammad; Kanapathipillai, Sangarapillai; Zarrabi, Khosrow et al. (2015) Stretch-dependent changes in surface profiles of the human crystalline lens during accommodation: a finite element study. Clin Exp Optom 98:126-37 |
| Hernandez, Victor M; Cabot, Florence; Ruggeri, Marco et al. (2015) Calculation of crystalline lens power using a modification of the Bennett method. Biomed Opt Express 6:4501-15 |
| Nankivil, Derek; Maceo Heilman, Bianca; Durkee, Heather et al. (2015) The zonules selectively alter the shape of the lens during accommodation based on the location of their anchorage points. Invest Ophthalmol Vis Sci 56:1751-60 |
Showing the most recent 10 out of 53 publications
