PURPOSE: To compare the position of the iris-fixated phakic intraocular lens (pIOL) in preoperative simulation and after implantation using anterior segment optical coherence tomography (AS-OCT). SETTING: Department of Ophthalmology, Academic Hospital Maastricht, Maastricht, The Netherlands. METHODS: In this prospective study, the morphometrics of the anterior chamber were analyzed using preoperative pIOL simulation and postoperative images assessed with AS-OCT. Patients' eyes were examined before and 6 months after pIOL implantation. The measured distances were from the center of the pIOL to the endothelium, from the edge of the pIOL to the endothelium (nasal and temporal side), and from the back of the pIOL to the crystalline lens. RESULTS: Thirty-four eyes (18 patients) were examined. All morphometric parameters showed highly significant correlations and small mean differences between preoperative and postoperative measurements. However, the distance from the nasal edge of the pIOL to the endothelium and the distance from the pIOL to the crystalline lens showed a statistically significant difference between the preoperative simulation and the actual postoperative measurements (P = .045 and P = .001, respectively). The ranges of agreement between all preoperative simulations and postoperative measurements ranged between 0.24 mm and 0.29 mm. CONCLUSIONS: Preoperative simulation was a useful additional tool in the selection of patients considering pIOL implantation and in ensuring the long-term safety of pIOLs. However, clinicians should be aware of the range between the preoperative simulation and the postoperative measurements.