To evaluate anterior segment alterations with age and during accommodation in different age groups.
Department of Ophthalmology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
Fifty-three subjects (101 normal eyes) were enrolled in this study and divided into 3 age groups: younger than 30 years (Group 1), between 31 years and 44 years (Group 2), and older than 45 years (Group 3). The total amplitude of accommodation was determined with a defocusing technique, and anterior segment measurements were performed by partial coherence interferometry.
Group 1 comprised 32 eyes; Group 2, 37 eyes; and Group 3, 32 eyes. The total amplitude of accommodation decreased with age (P<.0001). With the target position at infinity, the lens thickness (LT) and anterior segment length (ASL) increased and the anterior chamber depth (ACD) decreased significantly with age (P<.0001). During accommodation in the youngest group, the mean change in LT was 36.3 μm/diopter (D) and in ACD, −26.7 μm/D. The mean accommodation-induced ACD change was −0.08 mm ± 0.06 (SD) in Group 1, −0.064 ± 0.087 mm in Group 2, and −0.03 ± 0.06 mm in Group 3 (P = .0004). The mean LT change during near fixation was 0.109 ± 0.063 mm in Group 1, 0.103 ± 0.136 mm in Group 2, and 0.006 ± 0.05 mm in Group 3 (P<.0001). The mean ASL change during accommodation was 0.029 ± 0.037 mm, 0.039 ± 0.114 mm, and −0.023 ± 0.051, respectively (P<.0001).
In addition to forward movement of the anterior lens surface with age, the posterior surface moved backward. Alterations in LT and ACD sufficient for a unit of refractive power change during accommodation might be smaller than previously thought. Anterior shifting of the lens may also participate in the accommodative response.