Comparison of IOL Master, A-scan and Orbscan II for Measurement of Axial Length and Anterior Chamber Depth

Kim, Hyo Jin; Kim, Hyun Jin; Joo, Choun Ki

Abstract

PURPOSE
The purpose of the study was to compare IOL Master, A-scan and Orbscan about axial length(AL) and anterior chamber depth(ACD) measurement for IOL power calculation. METHODS: We evaluated AL and ACD using the IOL Master, A-scan and Orbscan. The subjects included were cataractous 66 eyes, pseudophakic 31 eyes, refractive surgery 24 eyes, keratoconus and keratoplasty 9 eyes. The AL length was measured with the non-contact optical biometry(IOL Master) and contact biometry (A-scan). The dirrerences in anterior chamber depth were compared among the aforementioned two methods and optical Orbscan. RESULTS: The average AL of 64 eyes of cataract patients was 23.85+/-1.88 mm in IOL Master and 23.76+/-1.78 mm in A-scan. There was no statistically significant difference(p>0.05). The mean ACD was 3.04+/-0.51 mm with IOL Master, 2.87+/-0.76 mm with A-scan and 3.09+/-0.54 mm with Orbscan. The differences among the methods weren't statistically significant(p>0.05) but ACD of A-scan were measured shorter than ones in IOL Master and Orbscan. Two eyes were unable to be examined by IOL Master due to the dense cataract. The ACD between IOL Master and A-scan was significantly different in pseudophakic eyes(p<.001). But The AL and ACD were not significantly different in refractive surgery, keratoconus and keratoplasty groups(p>0.05). CONCLUSIONS: The AL and ACD using IOL Master with non-contact and easy method in comparison A-scan, Orbscan weren't significantly different in cataract, refractive surgery, keratoconus and kelatoplasty. And the ACD of pseudophakic eye measured with IOL Master was better than A-scan. But the AL of some patients who had mature cataract weren't measured using IOL Master.