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

Objective: 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.