OBJECTIVES: Cost-effectiveness models in age-related macular degeneration use the utilities based on the better-seeing eye, because this mainly influence quality of life. Most models use the utility as if we only treat better-seeing eyes, although in trials the majority of the treated eyes are the poorer-seeing eyes. This discrepancy results in overestimating the QALY. Therefore a correction should be applied. The objective of this study is to estimate the influence on the (incremental) cost-effectiveness when correcting for the poorer-seeing eye. METHODS: An existing Markov model comparing three treatment frequencies of Bevacizumab (Avastin) is used, to investigate the effect of the correction of the poorer-seeing eye. We examined several scenarios of the poorer-seeing eye; no influence(0%), 10% and 20% influence of the utility of the better-seeing eye. In addition, it can be argued that treating the poorer-seeing eye has a preventive function, as it can become the future better-seeing eye. In the model a switch of the better-seeing eye is assumed after two and four years. RESULTS: By including the correction of the utility of the poorer-seeing eye the incremental cost-effectiveness ratio’s (ICER) change from €5,260, €31,167 and €3,712, to respectively €10,375, €60,124 and €7,377 (20% influence). Lowering the influence from 20% to 0% has an effect of respectively, €13,706, €78,314 and €9,796. When inserting a switch at two and four years, the ICER reduces from €10,375, €60,124 and €7.377 to respectively €7,325, €53,649 and €4,848 at four years and almost half at 2 years. CONCLUSIONS: The results show that overestimating the QALY by excluding the poorer-seeing eye results in a lower incremental cost-effectiveness. Poorer-seeing eyes should be used when modeling eye-diseases. Whether the poorer-seeing eye contributes 20%, 10% or 0% has a small impact on the change in ICER’s. The preventive function of treating the poorer-seeing eye should also be taken into account.