Early changes to dry eye and ocular surface after smallincision lenticule extraction for myopia

AIM： To investigate the early changes in dry eye symptoms, tear function and ocular surface following small-incision lenticule extraction（SMILE） for myopia.·METHODS： Ninety-seven consecutive patients（193 eyes）who underwent SMILE for myopia were observed in this longitudinal and retrospective study. Parameters evaluated included： subjective dry eye symptoms（dryness, foreign body sensation and photophobia）, tear film breakup time（TBUT）, Schirmer Ⅰ test without anesthesia（S Ⅰ T）, tear meniscus height（TMH） and corneal fluorescein staining. Each parameter was evaluated before, and subsequently at 1d, 1wk, 1 and3 mo after surgery.·RESULTS： Compared with preoperative data, dryness was noted to be significantly increased at 1wk and 1mo postoperatively（P 〈0.01）. Symptoms of photophobia and foreign body sensation demonstrated significant differences at 1d and 1wk as compared with preoperative scores respectively（P 〈0.01）. These values were decreased at 1 and 3mo post-surgery（P 〉0.05）.Conversely the corneal staining scores were higher than the preoperative data at 1d, 1wk and 1mo（P 〈0.01）, but were close to the preoperative level at 3mo postoperatively. There was a significant decrease in TMH at 1wk and 1mo（P 〈0.01）, but the value was close to the preoperative level at 3mo postoperatively（P =0.16）. The examination outcomes of S Ⅰ T were significantly increased at 1d then reduced at 1wk after surgery（P 〈0.01）. Each value subsequently returned to the baseline value at 1 and 3mo（P 〉0.05）. TBUT was significantly decreased at all postoperative time points（P 〈0.01）.· CONCLUSION： SMILE resulted in mild dry eye symptoms, tear film instability and ocular surface damages; however, these complications can recover in a short period of time.