Rainbow Glare After Femtosecond-LASIK: Lessons Learned From 5 Consecutive Cases
Purpose
To investigate the phenomenon of rainbow glare as a predominant optical side-effect of femtosecond laser treatment in cornea refractive surgery by analysis of a series of 5 cases.
Methods
Five consecutive cases presenting with rainbow glare following Femtosecond Laser in situ keratomileusis (Femto-LASIK) with the Wavelight FS200 system (Alcon) were analyzed. Visual disturbances, color perceptual differences and observed grating patterns were recorded. Confocal microscopy was performed to evaluate the flap interface in all cases. Patients were monitored till resolution of symptoms and treatment options compared.
Results
Rainbow glare was noted in the immediate postoperative period in all patients. The typical perception involved the visualization of a grating pattern with the blue end of the spectrum adjacent to the light source, and the red end farthest away, corresponding to the perfect grating pattern of plasma disruption at the flap interface. The induced grating pattern was demonstrated on confocal microscopy as hyperreflective spotlike zones corresponding to the surgeon-programmed spot-and-line separation distance at the level of the flap interface. In one persistent case, a flap-lift enhancement with refractive correction delivered to the back surface of the flap led to the disappearance of symptoms.
Conclusion
Diffractive grating leading to persistent rainbow glare is created by the imprints of the femtosecond laser as it impacts the posterior surface of the LASIK flap. Laser ablation performed at the back surface of the flap can lead to resolution of symptoms.