 0.3 sodium hyaluronate eye drops can effectively supplement the shortage of tear and promote repair of corneal epithelium. On this basis, the investigators hypotheses that 0.3 sodium hyaluronate eye drops can prevent the recurrence of TCA. So, investigators intend to test effectiveness of 0.3 sodium hyaluronate drops to prevent the recurrence of TCA by a prospective, single center, randomized, controlled pilot study. In this study, 60 patients with TCA were randomly divided into control group and sodium hyaluronate treatment group and observed one year. 