Lens position change following cataract surgery in eyes with thick lenses: an SS-OCT based study

PURPOSE: To evaluate the impact of intraocular lens (IOL) positional change following cataract surgery, measured by swept-source optical coherence tomography (SS-OCT) in eyes with different lens thicknesses (LTs), and its influence on the accuracy of IOL power calculation. METHODS: This prospective cohort study enrolled patients who planned to undertake phacoemulsification and monofocal IOL implantation, and were divided into three groups according to the LT (LT<4 mm, 4 mm≤LT<5 mm, LT≥5 mm). Lens position change (δLP), measured by the anterior segment SS-OCT, was defined as the difference between the position of postoperative IOL and the equatorial plane of preoperative lens. The prediction errors (PEs) of Barrett Universal II (BUII), Kane, Emmetropia Verifying Optical and Pearl-DGS formulas were evaluated at least 1 year postoperatively. RESULTS: Totally 90 eyes of 90 patients were analysed. The overall average δLP was -0.12±0.60 mm. Eyes with LT≥5 mm had more negative δLP (-0.44±0.65 vs 0.02±0.65 and 0.04±0.49 mm) and myopic PE of all four formulas than the LT<4 mm and 4 mm≤LT<5 mm groups, respectively (all p<0.05). δLP was negatively correlated with LT (r=-0.264, p=0.012) and positively correlated with anterior chamber depth (ACD) (r=0.263, p=0.012). Backward stepwise multiple linear regression analyses further revealed LT was the only independent influencing factor of δLP (p<0.05). ACD and δLP were the independent influencing factors of the PE with the BUII formula, while LT and δLP were the independent influencing factors of the PE with the other formulas (all p<0.05). CONCLUSION: Postoperative forward IOL movement contributes to myopic PEs of eyes with thick lenses. TRIAL REGISTRATION NUMBER: NCT02182921.