Preoperative tear volume may affect LASIK recovery

Preoperative tear volume may affect recovery of the ocular surface after LASIK and could increase the risk for chronic dry eye, according to a study published in the January issue of Investigative Ophthalmology & Visual Science.

Keiko Konomi and colleagues from the Schepens Eye Research Institute, Boston, USA enrolled 24 patients undergoing LASIK. Tear break-up time, Schirmer testing with and without anaesthesia, rose bengal staining, central corneal sensitivity, nucleus-to-cytoplasmic ratio and globlet cell density were evaluated two weeks prior to surgery and one week, three months and nine months after surgery. Subjects were classified into two outcome groups, the non-dry eye group (NDEG) and the chronic dry eye group (CDEG), on the basis of dry eye status nine months after surgery.

All parameters, except rose bengal staining, deteriorated significantly after surgery but returned to preoperative levels within three to nine months. The CDEG group had significantly lower preoperative Schirmer test values with an without anaesthesia and were delayed in recovery after surgery in globlet cell density, rose bengal staining, Schirmer test values without anaesthesia and tear break-up time. Results of preoperative Schirmer tests without anaesthesia positively correlated with tear break-up time nine months after surgery.

The authors believe that these findings may help ophthalmologists to determine if pre-treatment is necessary before surgery or if surgery is appropriate at all.