COMPARATIVE ANALYSIS OF SWEPT SOURCE OCT BASED BIOMETER ARGOS AND OPTICAL LOW-COHERENCE REFLECTOMETRY BASED LENSTAR LS 900 FOR TORIC INTRAOCULAR LENS

To evaluate the level of agreement, repeatability, and correlation between the measurements provided by a swept-source optical coherence tomography (OCT) based biometer (Argos) and an optical low-coherence interferometry (OLCI) based Lenstar LS 900 for calculation of a toric intraocular lens.

Department of Ophthalmology, Hospital de Santo André - Centro Hospitalar de Leiria, Leiria, Portugal

Retrospective study of eyes who underwent phacoemulsification with implantation of a AcrySof® IQ Toric IOL. Ocular biometric parameters were measured using both ARGOS and Lenstar LS 900. Axial length (AL), corneal power (K), steep axis of astigmatism and anterior chamber depth (ACD) were evaluated. IOL power using both biometry measurements were calculated with Barrett toric calculator.

Paired t tests (for normal distribution data) and Wilcoxon tests (for nonparametric data) were employed to compare the difference between the two devices. The Bland-Altman method was implemented to assess their agreement. P values less than .05 were considered statistically significant.

The study comprised 43 eyes (53.5% were right eyes) of 38 patients (50% were females). The mean age was 73.4 ± 10.5 years old.

There was no significant difference (p=0.189) between AL measured with the Lenstar (Mean = 23.70 ± 1.69 mm) and Argos (Mean = 23.74 ± 1.22 mm). Both flat keratometry (K1; Mean = 43.16 ± 1.37 D and 43.16 ± 1.46D, respectively) and steep keratometry (K2; Mean = 45.77 ± 1.71 D and 45.69 ± 1.74 D) were also not significantly different (p=0.793 and p=0.275).

Mean ACD was 3.23 ± 0.41 mm on Lenstar and 3.34 ± 0.37 mm on Argos; it was the only measurement statistically significant difference between both biometers (p<0.001). This resulted in a significant difference (p<0.001) in Barrett toric calculation of IOL (Mean = 19.85 ± 3.33 D using Lenstar measures and 20.31 ± 3.30 D using Argos measures).

ARGOS and Lenstar LS900 biometers agreement were overall good. However, the small but statistically significant differences in ACD measurements were enough to change the result of the IOL calculation that may affect the outcomes predictability of the toric IOL implantation.