Effectiveness of heparin eye drops in paraquat-induced ocular injury

Purpose: To evaluate the efficacy of heparin eye drops in the treatment of paraquat-induced ocular surface injury. Design and methods: In this retrospective study, we included 25 patients (31 eyes) with paraquat-induced ocular surface injury, who attended the Affiliated Hospital of Weifang Medical University between October 2008 and October 2013. The patients were split into two groups according to whether or not received heparin eye drops. The clinical data were compared between the two groups, i.e. clinical histories, results of examinations, treatments and outcomes. Results: Eleven patients (group A, 15 eyes) received prompt irrigation with 0.9% saline every two hours, 0.1% pranoprofen eye drops four times a day, 20% autologous serum every two hours, recombinant bovine basic fibroblast growth factor eye-gel two times a day, oral vitamin C 2.0 g and prednisone 30mg daily. Fourteen patients (group B, 16 eyes) received additional treatment with heparin eye drops. Ten eyes in group A and seven eyes in group B developed a pseudomembrane on the ocular surface at significantly different rate (mean +/- SD) of 1.20 +/- 1.01 and 0.43 +/- 0.51, respectively (t = 2.66, p = 0.01). Seven eyes among 10 had a pseudomembrane reoccurred in group A while none had a pseudomembrane reoccurred in group B (Fisher's exact test, p = 0.01). No significant differences were seen in the duration of epithelial recovery between the two groups: 15.13 +/- 5.13 days in group A and 16.81 +/- 5.56 days in group B (t = 0.87, p = 0.39). After the treatment, mild corneal opacity and pannus were observed in five patients of group A and four patients of group B, without any significant difference between the two groups (p = 0.70). Conclusions: The paraquat-induced ocular surface injury observed in this case series was characterized by the formation of conjunctival pseudomembrane with good prognosis and mild complications. Heparin eye drops reduce the occurrence, especially the reoccurrence of pseudomembrane. Further studies are warranted.