Purpose: To evaluate whether the outcome of negative dysphotopsia treatment by implantation of a Sulcoflex intraocular lens (IOL) can be understood using individual biometry and optical modeling data. Setting: University Eye Clinic, Maastricht University Medical Centre, Maastricht, the Netherlands. Design: Retrospective case series. Methods: Patients with negative dysphotopsia were treated with supplementary implantation of a sulcus-fixated IOL. Preoperative and postoperative ray-tracing optical models of eyes with negative dysphotopsia were constructed in the Zemax Optic Studio program using individual biometric data. The relationship between biometric parameters, ray-tracing data, and the course of negative dysphotopsia was evaluated. Results: The study comprised 8 patients (10 eyes). After surgery, negative dysphotopsia resolved completely in 6 eyes, partially in 2 eyes, and persisted in 2 eyes. There was no relationship between the course of negative dysphotopsia and age, IOL power, or individual biometry results other than a larger angle ? that was observed in 2 patients with persistent negative dysphotopsia after surgery. Preoperative ray-tracing models showed a decrease in light irradiance at the periphery relative to the center of visual field. After sulcus-fixated IOL implantation, this decrease partially resolved, in particular, for a small pupil aperture (P < .05), and it was more prominent in patients in whom negative dysphotopsia resolved completely than in those with partial or persistent negative dysphotopsia (P = .065 at 1.5 mm aperture). Conclusions: Of all individual biometry results, only angle kappa showed a relationship with the course of negative dysphotopsia. In patient-specific optical modeling of sulcus-fixated IOL implantation, the increase in simulated light irradiance at the periphery was related to the course of negative dysphotopsia. (c) 2018 ASCRS and ESCRS