Purpose: To evaluate the effect of pupil dilation on the biometric parameters of the Lenstar LS 900 (Haag Streit AG, Koeniz, Switzerland).
Methods: In this cross-sectional study of 33 eyes with cataracts, axial length (AL), anterior chamber depth, intraocular lens (IOL) power, keratometry, and pupil diameter measurements were performed using Lenstar biometry before and after pupil dilatation. Intraobserver repeatability was assessed by taking 2 consecutive recordings of biometric parameters using Lenstar biometry in the undilated pupils of 30 eyes with cataracts.
Results: The mean difference in AL measurements from intraobserver readings was -0.001 ± 0.01 mm. The study group showed a statistically significant change in the first keratometry reading and anterior chamber depth values (P < 0.05); however, the mean difference in AL and IOL power was statistically insignificant between the undilated and dilated pupil Lenstar biometry readings. Three cases in the study group (9.1%) and 1 case in the control group (3.3%) demonstrated changes in IOL power >0.50 diopter.
Conclusions: Dilated and undilated pupil size did not affect the measurement of IOL using the Lenstar biometry.