Purchase this article with an account.
G.L. Van der Heijde, M. Dubbelman, G.J. Vrensen; Changes in Cortical and Nuclear Thickness of the Aging and Accommodating Human Crystalline Lens . Invest. Ophthalmol. Vis. Sci. 2003;44(13):234.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Scheimpflug slit images of the crystalline lens are distorted due to the refracting properties of the cornea and because they are obliquely viewed. We corrected for these distortions and measured the thickness of the different nuclear and cortical layers of the human crystalline lens with age and accommodation. Method: Scheimpflug images were made of the unaccommodated and accommodated right eye of 102 subjects ranging in age between 16 and 65 years and ray tracing was used to correct the digital images for corneal and lenticular refraction. The different nuclear and cortical layers of the human crystalline lens were determined using densitometry. The change with accommodation was analysed by stretching the profile of the densitogram of the unaccommodated lens to match the profile of the accommodated lens in a least square sense. Results: The growth of the cortex (µm/year) is approximately 7 times greater than that of the nucleus. The growth of the anterior cortex was found to be 1.5 times greater than that of the posterior cortex. It was also found that specific parts of the cortex, known as C1 and C3, showed no significant change in thickness with age, and that the growth of the cortex is entirely due to the increase in thickness of the C2 zone. With accommodation, the thickness of the cortex remains constant, while there is a uniform thickening of the nucleus. Conclusions: The sudden change in stretch at the transition between anterior cortex and nucleus indicates an abrupt change in the stiffness of the lens. The nucleus, of which the thickness changes with accommodation, is surrounded during the growth of the lens by a continuously increasing cortex, and this could possibly play a role in the occurrence of presbyopia.
This PDF is available to Subscribers Only