Establishment of an optical model based on the eyes of emmetropic children

Abstract

Objective To establish an optical model of the emmetropic eye based on the ocular parameters of emmetropic children. Methods Based on the data of ″the Anyang Childhood Eye Study″ that included corneal curvature radius, corneal thickness, anterior chamber depth, crystalline lens thickness, refraction and axial length, we used ZEMAX software and the data of the right eyes to establish an optical model of the emmetropic eye that conformed to the features of emmetropic eyes in Chinese children. Results A total of 332 emmetropic children were included in the study. Their mean age was 7.1±0.4 years and mean spherical equivalent was 0.11±0.24 D. The optical parameters for the model of the emmetropic eye in children were: Cornea: 7.78 mm anterior corneal curvature radius, -0.18 asphericity coefficient, 6.4 mm posterior corneal curvature radius, -0.60 asphericity coefficient, 0.54 mm corneal thickness, and 1.376 refractive index; Anterior chamber: 3.00 mm for depth and 1.336 for the refractive index; Crystalline lens: 12.4 mm anterior corneal curvature radius, -0.94 asphericity coefficient, -8.1 mm posterior corneal curvature radius, 0.96 asphericity coefficient, and 3.55 mm thickness and gradient refractive index; Vitreous: 15.94 mm depth, 1.336 refractive index, and -12.3 mm retinal curvature radius; Axial length: 23.03 mm; Total refractive power: 62.55 D. Conclusion We have established an optical model that conforms to the features of emmetropic eyes in children. The optical model has a total refractive power of 62.55 D and axial length of 23.03 mm, and can be used as a reference for studying emmetropization and myopia in children. Key words: Children; Myopia; Emmetropic eye; Schematic eye; Optical model