High incidence of rainbow glare after femtosecond laser assisted-LASIK using the upgraded FS200 femtosecond laser.
BACKGROUND
To compare the incidence of rainbow glare (RG) after femtosecond laser assisted-LASIK (FS-LASIK) using the upgraded FS200 femtosecond laser with different flap cut parameter settings.


METHODS
A consecutive series of 129 patients (255 eyes) who underwent FS-LASIK for correcting myopia and/or astigmatism using upgraded WaveLight FS200 femtosecond laser with the original settings was included in group A. Another consecutive series of 129 patients (255 eyes) who underwent FS-LASIK using upgraded WaveLight FS200 femtosecond laser with flap cut parameter settings changed (decreased pulse energy, spot and line separation) was included in group B. The incidence and fading time of RG, confocal microscopic image and postoperative clinical results were compared between the two groups.


RESULTS
There were no differences between the two groups in age, baseline refraction, excimer laser ablation depth, postoperative uncorrected visual acuity and refraction. The incidence rate of RG in group A (35/255, 13.73%) was significantly higher than that in group B (4/255, 1.57%) (P < 0.05). The median fading time was 3 months in group A and 1 month in group B (P > 0.05).The confocal microscopic images showed wider laser spot spacing in group A than group B. The incidence of RG was significantly correlated with age and grouping (P < 0.05).


CONCLUSIONS
The upgraded FS200 femtosecond laser with original flap cut parameter settings could increase the incidence of RG. The narrower grating size and lower pulse energy could ameliorate this side effect.
['Zhang|Yu|Y|', 'Chen|Yue-Guo|YG|http://orcid.org/0000-0003-2720-7135']
D000328:Adult D001251:Astigmatism D019466:Glare D006801:Humans D015994:Incidence D020731:Keratomileusis, Laser In Situ D054018:Lasers, Excimer D018613:Microscopy, Confocal D009216:Myopia D012029:Refraction, Ocular D012189:Retrospective Studies D013524:Surgical Flaps D041623:Tomography, Optical Coherence D014786:Vision Disorders D014792:Visual Acuity
Incidence Rainbow glare FS200 femtosecond laser Fs-LASIK