Estimation of the full shape of the crystalline lens from OCT: validation using stretched donor lenses.

Quantifying human crystalline lens geometry as a function of age and accommodation is important for improved cataract and presbyopia treatments. In previous works we presented as a basis of 3-D functions to represent the full shape of the crystalline lens . Also, we presented the application of to estimate the full shape of the lens from 3-D optical coherence tomography (OCT) images, where only the central part of the lens -visible through the pupil- is available. The current work presents a validation of the use of to estimate the full shape of dis-accommodated lenses. We used 14 crystalline lenses from donor eyes (11-54 y/o) mounted in a lens stretcher, and measured the geometry and the power of the lenses using a combined OCT and ray tracing aberrometry system. , the full extent of the lens is accessible from OCT because the incident light is not blocked by the iris. We measured in non-stretched (fully accommodated) and stretched (mimicking dis-accommodated lenses) conditions. Then, we simulated computationally conditions on the obtained lenses geometry (assuming that just the portion of the lens within a given pupil is available), and estimated the full shape using The mean absolute error (MAE) between estimated and measured lens' diameters and volumes were MAE = 0.26 ± 0.18 mm and MAE = 7.0 ± 4.5 mm, respectively. Furthermore, we concluded that the estimation error between measured and estimated lenses did not depend on the accommodative state (change in power due to stretching), and thus are also useful for the full shape estimation of dis-accommodated lenses.