© 2011 Wichtig Editore - ISSN 1120-6721 Eur J Ophthalmol ( 2011 ; : 5) 597-603 21 597 DOI: 10.5301/EJO.2011.6253 INTRODUCTION There is experimental evidence in the literature show- ing that age-related changes occur in the crystalline lens. These changes are more noticeable in middle age and in- clude increased hardness (1-3), increased light scattering from the zones of discontinuity (4, 5), loss of ability to un- dergo accommodative changes (6-10), changes in spheri- cal aberration (7), changes in refractive index distribution (11-14), increased thickness (12-17), increased mass (4, 15-19), and increased anterior and posterior surface curva- tures (2). It is uncertain why all these physiologic changes take place. Factors like increased hardness, loss of ability A simple description of age-related changes in crystalline lens thickness Mari Carmen García-Domene 1 , Mª Amparo Díez-Ajenjo 1,2 , Víctor Gracia 1 , Adelina Felipe 2 , José M. Artigas 2 1 Fundación Oftalmológica del Mediterráneo, Valencia - Spain 2 Departamento de Óptica-Facultad de Física, Universidad de Valencia, Burjassot (Valencia) - Spain PURPOSE. An increase in lens thickness is often described as a linear function of age. However, con- tradictory opinions exist about whether the lens thickness continues to increase after 50 years of age. Differences in slope exist between this increase in younger and older people, but these findings are in- consistent with the linear behavior of an increase in the lens thickness throughout life. We investigated among different functions, including slope variation, which would be the best to show the relation between lens thickness and age. An available model portraying lens growth could be advantageous in many practical applications. The possibility of differences between sexes in lens thickness growth is also analyzed. METHODS. We evaluated 102 eyes of patients aged between 15 and 84 years: 41 men, 61 women. The biometric measurements were performed with the aid of the OcuScan ® (Alcon, USA). RESULTS. Both logarithmic and potential functions provide a good fit for the data (R 2 =0.905 and 0.906, respectively). The results do not show significant differences between men and women in any age range, nor when the data of the whole sample are considered (p=0.29). CONCLUSIONS. The best fits for the data are both logarithmic and double logarithmic functions. Accord- ing to this model, lens growth continues throughout life, but after 50 years, age-related thickness variations are lower than statistical variability. No differences were found between the sexes. KEY WORDS. Aging, Crystalline lens thickness Accepted: December 5, 2010 ORIGINAL ARTICLE to undergo accommodative changes, among others, relate directly, either causally or consequentially, to age-related presbyopia increment. For this reason, and because these changes mainly affect middle-aged subjects, it is accepted that they may be a consequence or a cause of presby- opia. An increase in lens thickness is a morphologic change that affects age-related visual quality evolution, among other situations. Lens growth occurs through the addition of epi- thelial cells migrating from the proliferative zone at the lens outer equatorial edge. These cells differentiate into elon- gated fiber cells extending toward the lens anterior and posterior poles. The result is a layering of the newer lens