Axial elongation following prolonged near work in myopes and emmetropes

Background/aims To investigate the influence of a period of sustained near work upon axial length in groups of emmetropes (EMM) and myopes. Methods Forty young adult subjects (20 myopes and 20 emmetropes) were recruited for the study. Myopes were further classified as early onset (EOM), late onset (LOM), stable (SM) or progressing (PM) subgroups. Axial length was measured with the IOLMaster instrument before, immediately after and then again 10 min after a continuous 30 min near task of 5 D accommodation demand. Measures of distance objective refraction were also collected. Results Significant changes in axial length were observed immediately following the near task. EOM axial length elongated on average by 0.027 +/- 0.021 mm, LOM by 0.014 +/- 0.020 mm, EMM by 0.010 +/- 0.015 mm, PM by 0.031 +/- 0.022 mm and SM by 0.014 +/- 0.018 mm. At the conclusion of the 10 min regression period, axial length measures were not significantly different from baseline values. Conclusion Axial elongation was observed following a prolonged near task. Both EOM and PM groups showed increases in axial length that were significantly greater than emmetropes.