Abstract： Objective To compare the axial length (AL) measured by Lenstar and contact A-Scan in the patients with idiopathic macular hole and study the correlation between the difference of the two measurements and the foveal thickness measured by optical coherence tomography (OCT).Methods Twenty-seven eyes of 26 idiopathic macular hole patients (IMH group) and 27 eyes of 25 patients with mild cataract (control group) were enrolled in this study.Foveal thickness was measured with 3D OCT.The AL was measured by Lenstar and contact A-Scan,and the consistency of the two measurements was determined by Bland Altman analysis.The correlation between the difference of the two measurements and foveal thickness was analyzed by Pearson correlation analysis.Results Mean foveal thickness of IMH and control eyes were (372.85±60.02) μm and (243.44±22.50) μm,respectively.The difference between the foveal thickness of the two groups was highly significant (t=-10.490,P＜0.001).In the IMH group,the AL measured by Lenstar and contact A-Scan were (23.20± 1.12) mm and (23.18± 1.13) mm,respectively,the difference between the two measurements was not statistically significant (t =-0.549,P =0.588),whereas in the control group,the AL was (23.41 ± 0.72) mm by Lenstar and (23.33 ± 0.74) mm by contact A-Scan,the two measurements were significantly different (t=-4.832,P＜0.001).However,no correlation was found by Pearson correlation analysis between the difference of the two measurements and the foveal thickness in either IMH or control group (r=0.181,-0.141; P＞0.05).Conclusions Although there is no difference of axial length measurements using Lenstar and contact A-Scan in IMH eyes,in clinical measurements the results of two instruments should be taken into comprehensive consideration.