ABSTRACT Aim To assess the relationship between systemic inflammation markers and ocular surface parameters in hazelnut harvesters. Material and Method This prospective study included 30 patients presenting with moderate ocular surface diseases during the hazelnut harvesting season. A detailed ophthalmological examination was performed during the harvesting season and the first month after the end of treatment (control). Schirmer test, tear break-up time (TBUT), and ocular surface disease index (OSDI) scores were determined. In complete blood count analysis, in addition to the evaluation of inflammatory cells, the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) were calculated. Results Eosinophil percentage had a high level of negative correlation with the TBUT and Schirmer values and a high level of positive correlation with the OSDI score during the hazelnut picking season (r = –0.727, r = –0.735, r = 0.750, respectively). During the hazelnut harvesting season, the NLR and SII parameters had a moderate level of negative correlation with the TBUT (r = –0.29 and r = −0.276) and Schirmer (r = –0.33 and r = −0.298) values and a moderate level of positive correlation with the OSDI score (r = 0.389 and r = 0.264). Conclusion In hazelnut harvesters, ocular allergy and inflammation may be associated with systemic biomarkers.