Laughton DS, et al. - Researchers examined 20 participants of age 34–41 years to quantify accommodative biometric changes longitudinally and also to ascertain the impact of age-related ocular structural changes on the accommodative response preceding the onset of presbyopia. They found a reduction in anterior chamber depth and an increase in crystalline lens thickness and axial length during accommodation. They found no variations (after 2.5 years) in the following criteria: the change in anterior chamber depth, crystalline lens thickness and axial length per dioptre of accommodation. They did not find any significant relationship between increment in disaccommodated crystalline lens thickness with age and the reduction in accommodative response. They supported the Helmholtz theory of accommodation and suggested an improvement in lenticular stiffness as a primary cause of presbyopia onset.