Purpose Eye dedicated proton therapy PT facilities are used to treat malignant intraocular lesions, especially uveal melanoma UM . The first commercial ocular PT beamline from Varian was installed in the Netherlands. In this work, the conceptual design of the new eyeline is presented. In addition, a comprehensive comparison against five PT centers with dedicated ocular beamlines is performed, and the clinical impact of the identified differences is analyzed. Material Methods The HollandPTC eyeline was characterized. Four centers in Europe and one in the United States joined the study. All centers use a cyclotron for proton beam generation and an eye dedicated nozzle. Differences among the chosen ocular beamlines were in the design of the nozzle, nominal energy, and energy spectrum. The following parameters were collected for all centers technical characteristics and a set of distal, proximal, and lateral region measurements. The measurements were performed with detectors available in house at each institution. The institutions followed the International Atomic Energy Agency IAEA Technical Report Series TRS 398 Code of Practice for absolute dose measurement, and the IAEA TRS 398 Code of Practice, its modified version or International Commission on Radiation Units and Measurements Report No. 78 for spread out Bragg peak normalization. Energy spreads of the pristine Bragg peaks were obtained with Monte Carlo simulations using Geant4. Seven tumor specific case scenarios were simulated to evaluate the clinical impact among centers small, medium, and large UM, located either anteriorly, at the equator, or posteriorly within the eye. Differences in the depth dose distributions were calculated. Results A pristine Bragg peak of HollandPTC eyeline corresponded to the constant energy of 75 MeV maximal range 3.97 g cm2 in water with an energy spread of 1.10 MeV. The pristine Bragg peaks for the five participating centers varied from 62.50 to 104.50 MeV with an energy spread variation between 0.10 and 0.70 MeV. Differences ...