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DLK after LASIK with femtosecond flaps linked to laser energy, flap size
Diffuse lamellar keratitis after LASIK with femtosecond laser flap creation resulted largely from higher laser energy and greater flap diameter, a large study found.
The incidence of diffuse lamellar keratitis (DLK) typically ranges from 0.2% to 19.4% after flap creation with a femtosecond laser and from 0.1% to 7.7% after flap creation with a microkeratome, the study authors said.
“With the increased use of the femtosecond laser for flap creation, there is interest in understanding this phenomenon,” they said. “Studies have shown that high laser energy levels and the ensuing photodisruption-induced tissue injury and accumulation of gas bubbles can lead to an increased inflammatory response and DLK.”
The retrospective study included 801 eyes of 419 patients with a mean age of 38 years; 382 patients underwent binocular LASIK, and 37 patients underwent monocular LASIK.
An IntraLase 60 kHz femtosecond laser (Abbott Medical Optics) was used to create LASIK flaps; stromal ablation was performed with a Technolas 217 excimer laser (Bausch + Lomb).
At 1 day and 1 week postoperatively, uncorrected and corrected distance visual acuities were recorded.
Study results showed that 99 eyes (12.4%) of 70 patients developed DLK.
A higher incidence of DLK was associated with larger flap diameter (P = .0171), increased raster energy (P = .0033) and increased side-cut energy (P = .0037).
Patients with DLK were less likely than their healthy counterparts to attain corrected distance visual acuity of 20/20 or better on the first day after surgery (P = .0453), the authors said. At 1 week, there was no difference in corrected distance visual acuity.