Anterior movement of the crystalline lens in the process of accommodation in children.

PURPOSE To investigate changes of crystalline lens position during accommodation in children with emmetropia, myopia, and hyperopia. METHODS A total of 188 children (372 eyes) from 4 to 19 years old (mean age 11.3+/-4.43) with cycloplegic refractive error within a range +9.00 D to -9.00 D were enrolled. After a general ophthalmic examination, ultrasound biometry was performed, with the eye at a maximal accommodative effort. Cycloplegia was induced by triple installation of 1% tropicamide drops and 30 minutes later the biometric examination was repeated. RESULTS In emmetropic eyes in the process of accommodation, the anterior pole of the crystalline lens moved forward by 0.144+/-0.14 mm (p< or =0.001); the position of the posterior pole did not change. In myopic eyes, the anterior pole moved forward by 0.071+/-0.13 mm (p< or = 0.001) and the posterior pole moved backward by 0.039+/-0.10 mm (p=0.003). In hyperopic eyes, the whole lens translocated anteriorly: anterior pole moved forward by 0.242+/-0.16 mm (p< or = 0.001) and posterior pole moved forward by 0.036+/-0.09 mm (p< or = 0.001). Differences among emmetropia, myopia, and hyperopia were statistically significant. Forward movement of the posterior pole correlated with a low axial length of the eye, and also with plus refractive error and with a smaller accommodative increase of lens thickness. CONCLUSIONS In children, accommodative changes of the crystalline lens position depend on refractive status.