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Ioanna Kontari, George Asimellis, A. John Kanellopoulos; A novel model of digitized clinical validation of femtosecond LASIK flap diameter and opaque bubble layer (OBL) incidence. Invest. Ophthalmol. Vis. Sci. 2013;54(15):3109.
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© ARVO (1962-2015); The Authors (2016-present)
The development of digital, quantitative and accurate analysis of LASIK flap diameter and OBL occurrence.
Flaps from 100 consecutive myopic and hyperopic LASIK patients, treated with the Alcon-WaveLight FS200 femtosecond and EX500 excimer lasers were digitally recorded and processed. Flap dimensions and OBL extent was evaluated utilizing a newly-developed digital procedure with a commercially available image processing software. Specifically, the flap creation report image provided by the FS200 internal system was analyzed digitally and calibrated on a scale converting pixels to measurable length in mm. In a similar fashion, the OBL occurrence was measured as a percentage of the actual flap surface area.
For the myopic cases, with planned flap diameter 8.00 (n = 20) and 8.50 mm (n = 60), a small negative bias was discovered (- 0.15 mm and -0.12 mm, respectively) with very small size fluctuation (diameter stdev = ± 0.04 and ± 0.03 mm, respectively). For the hyperopic cases, with planned flap diameter 9.50 mm (n = 20), a small positive bias was discovered (+ 0.06 mm), again with very small size variation (diameter stdev < 0.009 mm). Of the flaps studied, the majority (> 50%) had negligible or no OBL, and 20% less than 10% of the total flap area. The remaining had OBL to up of 20% of the total flap area. In all cases the flap was ‘delayed’, that is developing in areas already processed by the femtosecond laser, thus not interfering with the flap creation.
Τhis highly accurate, novel validation digital technique confirms the high reproducibility in flap dimensions and small occurrence of OBL in both myopic and hyperopic LASIK cases with the FS200 femtosecond laser.
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