Effect of cyclopentolate on ocular biometric parameters

Accurate measurement of axial length (AL), anterior chamber depth (ACD) and corneal curvature (CC) is essential for the calculation of IOL power according to different formulas. Assessing ACD is important to determine whether there is enough room for the PC-IOLs. It is evident that a shallow ACD and/or narrow angle may increase the risk of iris pigment chaffing, particularly when posterior chamber hyperopic PC-IOLs are implanted. Overestimation of ACD may result in corneal endothelial cell damage. Cyclopentolate is a synthetic antimuscarinic cycloplegic agent available in 0.5% and 1% solutions. It is widely accepted drug for patients of all ages providing excellent short-term cycloplegia. This study aims to compare the effect of cyclopentolate 1% on ocular biometric parameters – Anterior chamber depth (ACD), Lens thickness (LT) and Axial length (AL) before and after dilatation. In this observational study, 25 eyes of patients aged 45-75 years with significant cataract with nuclear sclerosis grading up to NO5NC5 C4 P4 (according to LOCS III) were included. The study was conducted for a duration of 3 months. Ocular biometric parameters ACD, LT and AL were measured using A-scan by immersion technique and compared before and after dilatation using 1% cyclopentolate and the data was analysed using paired T-test. Statistically significant difference (p value < 0.05) was observed in LT and ACD, while no significant difference was noted in AL post-cycloplegia. : Cycloplegia can significantly affect the ocular biometric parameters – deeper ACD and thinner LT. These changes in ocular biometric parameters should be considered in calculating IOL power to prevent refractive surprises after cataract surgery.