Comparison of corneal curvature and astigmatism measurements with four kinds of instruments before cataract surgery

Abstract

AIM: To compare corneal curvature and astigmatism values identified with OPD-Scan Ⅲ, IOL Master, Pentacam and KR-8900 in cataract patients and to evaluate the consistencies and differences. METHODS: In this prospective clinical trial, 45 cataract patients(86 eyes), received treatment at the Department of Ophthalmology in our hospital from April 2017 to June 2017, underwent corneal parameters measurements with four instruments: OPD-Scan Ⅲ, Pentacam, IOL Master, and KR-8900. Measurements included corneal curvature(K1, K2, Km)and astigmatism parameters. The results were assessed using the paired samples t tests, Pearson coefficient, and Bland-Altman plots. RESULTS: The difference of K1 value measured by OPD-Scan Ⅲ and IOL Master was significant(P2 and Km values between OPD-Scan Ⅲ and Pentacam or IOL Master(PP>0.05). All biometry measurements revealed good liner correlation(r=0.408-0.980, P1, K2 and Km measured by OPD-Scan Ⅲ and KR-8900. CONCLUSION: OPD-Scan Ⅲ and KR-8900 can be interchangeable for the measurements of corneal curvature, while the others are not directly interchangeable. The astigmatic results obtained from OPD-Scan Ⅲ are not completely interchangeable with KR-8900, IOL Master or Pentacam.

Keywords

• OPD-Scan Ⅲ
• corneal curvature
• astigmatism vector
• astigmatism vector