Diffuse lamellar keratitis after laser in situ keratomileusis with femtosecond laser flap creation

Abstract

To identify possible associations with the development of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) with femtosecond laser flap creation. University-based academic practice, Ann Arbor, Michigan, USA. Case-control study. Myopic LASIK was performed between October 2006 and December 2010 using an Intralase 60 kHz femtosecond laser for flap creation. Preoperative clinical characteristics, treatment parameters, and intraoperative and postoperative complications were recorded. Statistical comparisons were made using t, chi-square, and Fisher exact tests and repeated-measures logistic regression to adjust for inter-eye dependency. The study enrolled 801 eyes (419 patients). Ninety-nine eyes (12.4%) of 70 patients developed DLK; most cases comprised mild flap interface inflammation and were treated with a routine postoperative antiinflammatory regimen. Twenty-two eyes (2.7%) required more than 1 week of antiinflammatory treatment. There was a statistically significant increase in the incidence of DLK with larger flap diameter (P=.0171), higher side-cut energy (P=.0037), and higher raster energy (P=.0033). Patients with DLK were less likely to achieve corrected distance visual acuity of 20/20 or better 1 day postoperatively (P=.0453). The difference in acuity was no longer present at 1 week. There were no significant associations between the incidence of DLK and preoperative refractive error, flap thickness, ablation depth, or other treatment parameters. Diffuse lamellar keratitis after LASIK with femtosecond laser flap creation tended to be mild with little effect on visual acuity. Higher energy level for flap creation and larger flap diameter were associated with an increased risk for DLK.