Comparison of the accuracy of Canon KU-1 IOL measurer and VPLUS A/B scanner in axial length measurement.

Purpose: To evaluate the accuracy of Canon KU-1 IOL measurer (Japanese Canon Company) and VPLUS A/B scanner (French Quantel Company) in axial length (AL) measurement.

Methods: Canon KU-1 IOL measurer and VPLUS A/B scanner were used to measure axial length of human cataractous eyes before cataract surgery. Two hundred and twenty-two cases (433 eyes) were involved. The results were compared and the postoperative visual acuity, refractive results were recorded during the follow-ups to evaluate the accuracy of the two instruments.

Results: In the 222 cases (433 eyes), the absolute value of the measurement differences was 0.4 mm or above in 35 eyes, 0.8 mm or above in 17 eyes, 1.2 mm or above in 12 eyes, 2.0 mm or above in 5 eyes. The refractive error was less than 2.0 D in all patients. The mean values of ocular axial length by the two methods were 23.82 mm and 23.83 mm respectively and the difference had no statistic significance with compared t test (P = 0.902, two tail, alpha = 0.01).

Conclusion: The accurate AL measurements can be obtained with the two instruments and the measurement results should be analyzed comprehensively to obtain accurate values in the complicated cases.