Crystalline Lens Shape During Accommodation in Children

To determine how accommodation affects lens shape in myopic and non-myopic children.

Participants included 76 non-myopic (spherical equivalent refraction (SER): 0.00 to +1.75 D) and 18 myopic children (SER = -3.50 to -0.75 D) aged 5-12 years. Anterior and posterior lens surface shapes were determined by image processing and ray tracing of IOLMaster 700-generated B-scan images (six meridians per scan) at 0, 3, 6 and 9 D accommodation demands, expressed as refractive power vectors (M, J₀ and J₄₅).

For all children, anterior and posterior lens surface M and total lens power increased by means (±SD) of +0.45 ± 0.17, +0.23 ± 0.20 and +0.65 ± 0.32 D per dioptre of accommodation demand, respectively, with a shift towards a more equiconvex shape with increasing accommodation. J₀ and J₄₅ did not change significantly during accommodation (for anterior surface, p = 0.68 and 0.48, respectively; for posterior surface, p = 0.47 and 0.88, respectively). Myopic lenses had significantly lower anterior and posterior surface M and total lens power than non-myopic lenses (p < 0.05), but no significant differences were observed in astigmatic vectors except for anterior lens surface J₀. There were no interactions between accommodation demand and refractive error for any lens parameters (all p ≥ 0.13).

Myopic children have flatter lens surfaces than non-myopic children. Lens surface shape changes with accommodation are similar between myopic and non-myopic children.