Andrzej Grzybowski1,2, Ronald A Schachar3, Magdalena Gaca-Wysocka2, Ira H Schachar4, Barbara K Pierscionek5. 1. Institute for Research in Ophthalmology, Poznan 60-554, Poland. 2. Department of Ophthalmology, University of Warmia and Mazury, Olsztyn 10-082, Poland. 3. Department of Physics, University of Texas in Arlington, Arlington, Texas 76019, USA. 4. Department of Ophthalmology, Horngren Family Vitreoretinal Center, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California 94304, USA. 5. School of Science and Technology, Nottingham Trent University, Nottingham NG1 4FQ, UK.
Abstract
AIM: To compare the results of in vivo human high resolution image registration studies of the eye during accommodation to the predictions of mathematical and finite element models of accommodation. METHODS: Data from published high quality image registration studies of pilocarpine induced accommodative changes of equatorial lens radius (ELR) and central lens thickness (CLT) were statistically analyzed. RESULTS: The mean changes in ELR and CLT were 6.76 µm/diopter and 6.51 µm/diopter, respectively. The linear regressions, reflecting the association between ELR and accommodative amplitude (AAELR) was: slope=6.58 µm/diopter, r2 =0.98, P<0.0001 and between CLT and AACLT was: slope=6.75 µm/diopter, r2 =0.83, P<0.001. On the basis of these relationships, the CLT slope and the AAELR were used to predict the measured change in ELR (ELRpredicted). There was no statistical difference between ELRpredicted and the measured ELR as demonstrated by a Student's paired t-test: P=0.96 and linear regression analysis: slope=0.97, r2 =0.98, P<0.00001. CONCLUSION: Image registration with invariant positional references demonstrates that ELR and CLT equivalently minimally increase ∼7.0 µm/diopter during accommodation. The small equivalent increases in ELR and CLT are associated with a large accommodative amplitude. These findings are consistent with the predictions of mathematical and finite element models that specified the stiffness of the lens nucleus is the same or greater than the lens cortex and that accommodation involves a small force (<5 g). International Journal of Ophthalmology Press.
AIM: To compare the results of in vivo human high resolution image registration studies of the eye during accommodation to the predictions of mathematical and finite element models of accommodation. METHODS: Data from published high quality image registration studies of pilocarpine induced accommodative changes of equatorial lens radius (ELR) and central lens thickness (CLT) were statistically analyzed. RESULTS: The mean changes in ELR and CLT were 6.76 µm/diopter and 6.51 µm/diopter, respectively. The linear regressions, reflecting the association between ELR and accommodative amplitude (AAELR) was: slope=6.58 µm/diopter, r2 =0.98, P<0.0001 and between CLT and AACLT was: slope=6.75 µm/diopter, r2 =0.83, P<0.001. On the basis of these relationships, the CLT slope and the AAELR were used to predict the measured change in ELR (ELRpredicted). There was no statistical difference between ELRpredicted and the measured ELR as demonstrated by a Student's paired t-test: P=0.96 and linear regression analysis: slope=0.97, r2 =0.98, P<0.00001. CONCLUSION: Image registration with invariant positional references demonstrates that ELR and CLT equivalently minimally increase ∼7.0 µm/diopter during accommodation. The small equivalent increases in ELR and CLT are associated with a large accommodative amplitude. These findings are consistent with the predictions of mathematical and finite element models that specified the stiffness of the lens nucleus is the same or greater than the lens cortex and that accommodation involves a small force (<5 g). International Journal of Ophthalmology Press.
Entities:
Keywords:
accommodation; central lens thickness; equatorial lens radius; image registration
Authors: Andrzej Grzybowski; Ronald A Schachar; Magdalena Gaca-Wysocka; Ira H Schachar; Farhad Kamangar; Barbara K Pierscionek Journal: Graefes Arch Clin Exp Ophthalmol Date: 2017-11-16 Impact factor: 3.117
Authors: Aikaterini I Moulakaki; Daniel Monsálvez-Romín; Alberto Domínguez-Vicent; José J Esteve-Taboada; Robert Montés-Micó Journal: Int Ophthalmol Date: 2017-10-26 Impact factor: 2.031
Authors: Andrzej Grzybowski; Ronald A Schachar; Magdalena Gaca-Wysocka; Ira H Schachar; Barbara K Pierscionek Journal: Clin Ophthalmol Date: 2018-01-22