An in vivo confocal microscopy and impression cytology analysis of preserved and unpreserved levobunolol-induced conjunctival changes

PURPOSE. To provide an in vivo confocal microscopy (IVCM) and impression cytology analysis of preserved- and unpreserved levobunolol-induced changes of conjunctival epithelium. METHODS. 27 eyes of 27 patients were consecutively randomized to receive preserved or unpreserved levobunolol; all patients had a recent diagnosis of primary open angle glaucoma (POAG) or ocular hypertension and were not previously treated with topical medications. IVCM and impression cytology were performed before and after six months of therapy. Goblet cells density and a conjunctival epithelium regularity index were considered in the IVCM analysis, whereas impression cytology specimens were graded and scored in accordance with Nelson's method. RESULTS. After six months of therapy, IVCM and impression cytology parameters showed significant differences with respect to baseline in both groups (p < 0.001); significant differences were also found between the two groups ( p < 0.001). The IVCM analysis showed a goblet cells density reduction (61% and 17% from baseline, respectively in group 1 and 2) (p < 0.001) and an higher index of epithelial regularity (p < 0.001) in both groups; the impression cytology analysis showed an higher score in both groups (p < 0.001). CONCLUSIONS. All the IVCM and impression cytology parameters correlated well with the conjunctival modifications induced by the topical therapy, suggesting the less toxicity of unpreserved drugs.