Comparison Of Corneal Curvature And Astigmatism Measured By Three Different Devices Of Age-related Cataract

PurposeTo compare the difference,correlation and consistency of corneal curvature and astigmatism measured by Pentacam,IOL Master and iTrace of age-related cataract.MethodThis study included patients with 68 cataract patients(82 eyes).Flat keratometry(K1),steep keratometry(K2),mean keratometry(Km),cylinder at 0-degree meridian(J0)and cylinder at 45-degree meridian(J45)were measured by Pentacam,IOL Master and iTrace.The statistical differences between three instruments were assessed using the paired t tests,their correlation was evaluated by Pearson correlation analysis,and the agreement analysis was performed by Bland-Altman plots method.Results1.There was no statistical difference between the corneal curvature and astigmatism measured by Pentacam,IOL Master and iTrace of age-related cataract(P>0.05).2.Pearson correlation revealed a high correlation of corneal curvature(K1,K2,Km)and IOL dioptric power measured by Pentacam,IOL Master and iTrace(0.5<|r|,P<0.01),revealed a moderate correlation of corneal astigmatism(J0,J45)measured by IOL Master to Pentacam and iTrace(0.3<|r|<0.5,P<0.01),revealed a weak correlation of corneal astigmatism(J0,J45)measured by Pentacam between iTrace(0.1<|r|<0.3,P<0.05).3.The Bland-Altman plots showed that there are over 5%points outside 95%LoA between Pentacam and IOL Master when they measured K2 and J45,there are over 5%points outside 95%LoA between Pentacam and iTrace when they measured J0 and J45,there are over 5%points outside 95%LoA between IOL Master and iTrace when they measured J0 and J45.All of the measured value of 95%LoA rages are over 1.0D,so the three devices had incomparable results for corneal curvature and astigmatism.ConclusionThere was no statistical difference between the corneal curvature and astigmatism measured by Pentacam,IOL Master and iTrace,and the corneal curvature and astigmatism were correlated among the three devices.But the three devices had incomparable results for corneal curvature and astigmatism,which means they all can not directly interchanged,targeted selection is required for the measuring the corneal curvature and astigmatism by the different devices in the actual clinical process.