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E. Hermans, M. Dubbelman, G. L. van der Heijde, R. M. Heethaar; Volume of the Human Lens Nucleus During Accommodation. Invest. Ophthalmol. Vis. Sci. 2007;48(13):981.
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© ARVO (1962-2015); The Authors (2016-present)
To measure the volume of the nucleus of the human lens during static accommodation. The change in volume can be used to qualitatively characterize the compressibility of the nucleus material. Knowledge about volume and compressibility of the nucleus material allows a better understanding of the accommodation process.
Scheimpflug imaging is used to determine the cross-sectional shape of the human lens nucleus during accommodation. A parametric model of the cross-sectional geometry is fitted with the Hough transform to the gradient of corrected Scheimpflug images. Under the assumption of rotational symmetry, an estimation of the volume is obtained by integrating the cross-sectional outline of the nucleus around the circumference. The sample population, which consisted of five healthy subjects (age 16 to 32 years), was measured as a function of accommodation stimulus (range; from 0 to at least 7 diopters).
The average volume (+/- standard deviation) of the nucleus was 35.1 (+/- 3.7) mm3. The accuracy for an individual measurement of volume was 0.4 mm3. No significant change in volume in any of the five subjects could be determined during accommodation.
The finding that the volume of the nucleus did not change during accommodation implies that the Poisson’s ratio is near 0.5, indicating that the human nucleus mainly consists of incompressible material.
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