Paediatric Facial Anthropometry Applied to Spectacle Frame Design

Abstract

This thesis describes measurements of paediatric facial parameters that specifically relate to the design of spectacle frames. In the current market, the majority of paediatric spectacle frames are scaled down versions of frames designed for adults which assumes that facial characteristics do not change with growth. This often results in an ineffective delivery of any refractive correction prescribed at a critical time in a child’s development. Three-dimensional stereophotogrammetry was employed to capture images in a rapid, non-invasive manner. Fifteen paediatric facial measurements associated with spectacle frame parameters were measured using custom software in a sample of 1334 children observing differences in gender, ethnicity and Down’s syndrome. Principal findings: • The typically-developed White British children showed a definite emergence of the nasal bearing surface at a young age from which all parameters surrounding the nose narrowed with age. • A distinct nasal bearing surface emergence was not observed in either Chinese children or children with Down’s syndrome therefore requiring larger spectacle parameters in terms of frontal and splay angles, distance between rim and apical radius. • Chinese children and children with Down’s syndrome have a lower crest height and a shorter front to bend compared to typically-developed White British children and differences were detected in head width and pupillary distance between these two groups. • Children with Down’s syndrome are not wholly smaller or larger than typically-developed White British children but need their requirements to be incorporated into frame design to accommodate differences in facial development. Percentiles were calculated each of the largest study groups. This data combined with the model of facial growth and inter-relationships between facial measurements presented in this thesis will inform spectacle frame manufacturers on appropriate parameters and design features required to produce a more encompassing range of paediatric frames, resulting in a more stable and comfortable fit.