Abstract
Purpose: :
To compare the incidence of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) with flap creation using the IntraLase FS15, FS30, or FS60 femtosecond laser.
Methods: :
We retrospectively reviewed myopic LASIK cases performed using the IntraLase FS15, FS30, or FS60 femtosecond laser for flap creation from June 1, 2005 to June 1, 2007. Flap creation before January 19, 2006 was performed with the FS15 laser. The FS30 laser was used from January 19, 2006 to October 25, 2006, and subsequent cases were performed with the FS60 laser. The patients’ preoperative clinical characteristics, treatment parameters, intraoperative and postoperative complications were recorded. Statistical comparisons were made using t-tests, Chi-square, Fischer’s exact test, and analysis of variance.
Results: :
The records of 288 eyes of 152 patients were reviewed. Eighty-seven eyes of 46 patients were treated using the FS15 laser, 84 eyes of 45 patients with the FS30 laser, and 117 eyes of 61 patients with the FS60 laser. The overall incidence of DLK was 19%. The majority of DLK cases were Stage I (82%), diagnosed on postoperative day one (85%), and resolved by 2 weeks (87%). At postoperative week one, 59% had uncorrected visual acuity of 20/20 or better and 94% had uncorrected visual acuity of 20/40 or better. Similar visual acuity results were found in eyes that developed DLK (58% and 95%, respectively). Thirty-five percent of eyes diagnosed with DLK resolved with the standard postoperative regimen of topical corticosteroid eye drops 4 times per day. The other 65% were treated with more frequent topical corticosteroid eye drops. Only 5% required flap lift and irrigation.Patients who developed DLK on average had thinner corneal flaps (117µm vs. 120µm) (p=0.02) and decreased preoperative Schirmer’s <5mm (p=0.08). The incidence of DLK after LASIK differed among the FS15, FS30, and FS60 groups (p=0.05). However, there were statistically significant differences in the baseline and treatment characteristics among these three groups, including flap thickness and Schirmer’s test results (p<0.0001 and p=0.05, respectively).
Keywords: refractive surgery: complications • refractive surgery: LASIK • inflammation