The effect of near work on the anterior eye and associations with myopia: a narrative review.

The global prevalence of myopia has increased significantly in recent decades, and it is anticipated that half the population of the world will be myopic by 2050. The dramatic increase in myopia cannot be explained solely by genetic factors; hence, environmental factors such as near work may play an important role in myopia development. Near work activities involve accommodation, convergence, and pupil constriction, which lead to various mechanical changes that alter the structural and optical properties of the anterior eye. Mechanical changes associated with near work activities include ciliary body contraction, medial rectus contraction, lateral rectus relaxation, changes in the eyelid-cornea interaction, pupil size, and crystalline lens shape and position. These structural variations lead to optical changes including a change in spherical refractive power, astigmatism, accommodative convergence, higher order aberrations, and retinal image quality. Several differences in near work-related optical and structural changes have been observed between myopes and non-myopes. These differences elucidate mechanisms that potentially underpin near work-associated axial elongation and myopia development. This narrative review explores anterior segment structural and optical changes during near work and their potential mechanistic contribution to myopia development, while highlighting literature gaps that require further research.