Evaluation of Tear Osmolarity Changes After Photorefractive Keratectomy.

PMID 26488623


To assess tear film stability, ocular surface disease index (OSDI) score, Schirmer test value, tear film breakup time (TBUT), and tear osmolarity after photorefractive keratectomy (PRK). We enrolled 50 eyes from 25 patients who were PRK candidates (15 men, 10 women). The mean age was 31.9 ± 4.5 years. Dry eye severity was evaluated using OSDI questionnaire, TBUT, Schirmer test, and tear osmolarity preoperatively and in each postoperative follow-up visit during the 4-month follow-up period. Tear osmolarity changed from 302 ± 5.9 mOsm/L preoperatively to 308.8 ± 5.8 mOsm/L (P < 0.0001) and 304.1 ± 9.4 mOsm/L (P = 0.40) after 2 and 4 months, respectively. Schirmer test did not change significantly 4 months after PRK (P = 0.410). TBUT decreased significantly after 2 months and did not return to its preoperative value after 4 months. Subjective complaints measured by OSDI score, improved after 4 months compared with the preoperative level. Although dry eye tests (Schirmer, TBUT, and tear osmolarity) are abnormal 2 months after PRK, they returned to preoperative values after 4 months. We can conclude that post-PRK dry eye is a transient complication which will last less than 4 months with regular use of topical lubricants.