Agreement between IOLMaster 500 and Pentacam HR for keratometry assessment in type 2 diabetic and nondiabetic patients

AIM:To evaluate inter-device agreement of anterior keratometry obtained by the IOLMaster 500 and Pentacam HR in type 2 diabetic and non-diabetic patients.METHODS:Corneal measurements were sequentially performed in 60 diabetes mellitus(DM)and 48 age and sex-matched controls undergoing cataract surgery.Variables recorded included flat and steep keratometry,mean keratometry(Km),astigmatism magnitude,axis location,JO and J45 components.Bland-Altman plots and intraclass correlation coefficients were used for examination of agreement.Subgroup analyses were performed for astigmatism magnitude,diabetes duration,hemoglobin A1c(HbA1c)levels and diabetic retinopathy(DR)stage.RESULTS:Agreement for Km and astigmatism magnitude were considered good and moderate,with 95%limits of agreement(LoA)of-1.09 to 1.23 diopters(D)and-0.83 to 0.86 D in DM group,respectively;and-0.59 to 0.72 D and-0.98 to 0.75 D in non-DM group,respectively.In contrast,the 95%LoA for corneal axis exceeded the clinically relevant margins in both groups.In the total sample,only 41 eyes(38%)had a smaller than 5-degree difference.Diabetes duration,HbA1c levels and DR stage were not found to significantly affect agreement.Logistic regression showed that higher corneal power(P=0.021)and astigmatism magnitude(P=0.011)were associated with a decreased risk of having a difference in axis location greater than 10-degrees.CONCLUSION:In both groups,IOLMaster and Pentacam agree well for corneal power and moderately for astigmatism.However,axis location disagreement is frequent in eyes with flatter corneas and small amounts of astigmatism.