Noninvasive biomarkers to distinguish idiopathic Parkinson’s disease (iPD) from monogenic forms and track progression remain elusive. We applied nanoLCMS/MS to characterise the tear proteome of 77 iPD patients, seven LRRK2 mutation carriers and 86 agematched controls. Of the 1,011 proteins identified, 465 differed significantly between iPD and controls (p < 0.05); imposing a ≥2fold change yielded six robust candidates. ENOB, MUC5AC, LMNA, COX2 and PSB1 were upregulated, whereas K895L was reduced in iPD. Comparison with the LRRK2 cohort revealed 14 discriminant proteins, notably VATB2, PARK7, RS8 and PROL1. VATB2 and RS8 showed positive correlations with motor disability, as assed by the Unified Parkinson’s Disease Rating Scale part II (UPDRS II); in contrast, VATB2 was inversely linked to tear volume, while PROL1 exhibited a direct association. These findings demonstrate that tearfluid proteomics differentiates iPD from LRRK2associated Parkinson’s disease, illuminate’s diseasespecific pathways and mirrors clinical heterogeneity through a simple ophthalmic sample. The resulting protein panels provide promising noninvasive biomarkers for early diagnosis, patient stratification and therapeutic monitoring, warranting validation in larger longitudinal cohorts.