[Agreement of three keratometers in phakic patients]

To estimate the agreement between the results obtained from three keratometers in phakic patients without previous crystalline surgery and a healthy control group, taking into account its relationship with variables such as, age, gender and pathology of cataracts.

Descriptive study of the agreement of results between three corneal keratometry techniques in a sample of 56 patients enrolled consecutively in a Department of Ophthalmology. A group of 29 professionals of the Department was included as controls. Three keratometers were used: An Auto INDO KM-500, one incorporated into the laser scanning biometer IOL-Master and another in the autorefractor KR-8800. Agreement was estimated by intraclass correlation coefficient (ICC) and the presence of systematic errors was tested by Bland-Altman method and non-parametric regression (Passing and Bablok).

We selected 24 men, 49 women with a mean age of 48.2 years (SD 18.5, range 13 to 86 years). The agreement was very high in all measurements, with ICC ranging from a low of 0.86 (95% CI: 0.70 - 0.95) over 65 years to a maximum of 0.98 (95% CI: 0.96 - 0.99) in the youngest (under 40 years). No systematic, constant and proportional errors were detected among the three keratometers.

The keratometry was consistent between the three methods, although the correlation is lower in patients over 65 years, which may compromise the biometric studies in patients who undergo surgery for cataracts.