Comparison of IOLMaster(R) and A-Scan Ultrasound: Change in Axial Length After Vitrectomy in Macular Disease

PURPOSE: To evaluate the differences between IOLMaster(R) and A-scans in changes in axial length after vitrectomy in patients with macular disease. METHODS: Using IOLMaster(R) 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. RESULTS: 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(R) (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, p0.05, 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). CONCLUSIONS: The IOLMaster(R) is more useful than the A-scan when measuring axial length without refractive errors after vitrectomy in eyes with macular disease.

Comparison of IOLMaster(R) and A-Scan Ultrasound: Change in Axial Length After Vitrectomy in Macular Disease

PURPOSE: To evaluate the differences between IOLMaster(R) and A-scans in changes in axial length after vitrectomy in patients with macular disease. METHODS: Using IOLMaster(R) 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. RESULTS: 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(R) (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, p0.05, 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). CONCLUSIONS: The IOLMaster(R) is more useful than the A-scan when measuring axial length without refractive errors after vitrectomy in eyes with macular disease.

The Accuracy of Axial Length Measurement Using Partial Coherence Interferometrys

PURPOSE: IOLMaster(R), a non-contact device using partial coherence interferometry, serves as a new optical method for axial length determination. The accuracy of this device was analyzed by comparing the measurements from IOLMaster(R) and A-scan. METHODS: We measured the axial lengths in 150 eyes of 80 patients with IOLMaster(R) and A-scan. Then, we examined the difference of measurements between the IOLMaster(R) and A-scan according to the patients' age, refractive error, type of cataract, and existence of cataract. RESULTS: Axial length could not be measured with IOLMaster(R) in 12 eyes, which all had severe cataract. The measurements from IOLMaster(R) in both, the cataract group and the normal group, resulted 0.02mm longer than those from A-scan, but did not differ significantly (p>0.1). Also, there was no statistical difference of measurements between IOLMaster(R) and A-scan according to the patients' age, refractive error, and types of cataract (p>0.05). CONCLUSIONS: Axial length measurement with IOLMaster(R) shows no significant difference from A-scan measurement. Therefore, IOLMaster(R) can be a new clinical method of axial length measurement except for cases of a severe cataract.