To evaluate the differences between IOLMaster® and A-scans in changes in axial length after vitrectomy in patients with macular disease.

Using IOLMaster® and A-scans, we measured preoperative and postoperative axial length in 12 eyes with epiretinal membranes (ERM) and in 8 eyes with macular holes (MH). The relationship between the absolute error in axial length after vitrectomy and both methods was assessed using Mann-Whitney U test. The correlation to central macular thickness was evaluated by Spearman's correlation coefficient.

In eyes with ERM and MH, preoperative and postoperative axial lengths obtained with both methods had no significant difference ( p >0.05). The absolute error in axial length after vitrectomy was not significant using IOLMaster® (ERM: 0.07±0.05 mm, MH: 0.04±0.02 mm, p >0.05) but was significant using A-scan (ERM: 0.20±0.11 mm, MH: 0.30±0.07 mm, p <0.05). The correlation between the change of axial length after vitrectomy and the central macular thickness was poor (IOLMaster®: ERM; correlation coefficient = -0.182, p >0.05, MH; correlation coefficient = -0.054, p >0.05, A-scan: ERM; correlation coefficient = -0.210, p >0.05, MH; correlation coefficient = -0.156, p >0.05).

The IOLMaster® is more useful than the A-scan when measuring axial length without refractive errors after vitrectomy in eyes with macular disease.