Effect of pharmacologic pupil dilation on OLCR optical biometry measurements for IOL predictions

To determine the possible influence of pupil dilation on intraocular lens (IOL) power predictions made using optical biometry with Lenstar LS 900® (Haag-Streit AG, Koeniz, Switzerland).

A total of 72 eyes of 72 patients scheduled to undergo cataract surgery were prospectively examined using the optical low-coherence reflectometry (OLCR) optical biometer before and after pupil dilation with tropicamide 1%. The measurements made were axial length, central corneal thickness, anterior chamber depth (ACD), lens thickness, mean keratometry, corneal diameter (CD), and pupil diameter. Holladay II and SRK/T formulas were used to calculate IOL power. Agreement between the 2 measurement modes (with and without dilation) was assessed by calculating intraclass correlation coefficients (ICC) and constructing Bland-Altman plots.

The mean age of the patients was 74.71 ± 7.53 years (range 56-90). Among the variables determined, only ACD varied significantly according to pupil dilation (p<0.001). The ICC data revealed excellent intraobserver correlation between measurements made with and without dilation, except for CD. The IOL power predictions were unmodified.

The use of pupil dilation does not seem to influence measurements and IOL predictions made using this OLCR optical biometer.