To investigate the relationship among higher-order aberrations and night myopia

Objective To investigate the relationship between higher order aberrations and night myopia,and to explore the possible mechanism of the development of night myopia. Methods Sixty emmetropes were recruited. The Tracey iTrace Visual Function Analyzer were used to measure objective refraction spherical equivalent value and the higher-order aberration respectively in natural pupil. To compare the higher-order aberrations with the objective refraction spherical equivalent value and analyzed the relationship between them. Results At mesopic state the higher-order aberrations were increased with increasing pupil diameter exponentially. When the luminance level changed from photopic to mesopic state,Spherical Total increased 3.5-fold,RMS Coma Total 1.3-fold and RMS higher-order aberrations 1.3-fold. There was a positive correlation between night myopia and higher-order wavefront aberrations,coma-like aberrations or spherical-like aberrations. Conclusions At mescopic state there is-0.22D night myopia in emmetropes. Because of the inscreased pupil diameter at mescopic state,the aberrations of eyeball also increased and the optical quality of the eye decreased,the size and location of the circle of least confusion changed,which induced night myopia. Data suggests that eliminates the increased higher-order aberrations might be a fundamental method to resolve it.