Predictive Factor Analysis for Successful Performance of Iris Recognition-Assisted Dynamic Rotational Eye Tracking during Laser In Situ Keratomileusis
Accepted 19 August 2009. published online 06 November 2009.
Purpose
To analyze the predictive factors associated with success of iris recognition and dynamic rotational eye tracking on a laser in situ keratomileusis (LASIK) platform with active assessment and correction of intraoperative cyclotorsion.
Design
Interventional case series.
Methods
Two hundred seventy-five eyes of 142 consecutive candidates underwent LASIK with attempted iris recognition and dynamic rotational tracking on the Technolas 217z100 platform (Techolas Perfect Vision, St Louis, Missouri, USA) at a tertiary care ophthalmic hospital. The main outcome measures were age, gender, flap creation method (femtosecond, microkeratome, epi-LASIK), success of static rotational tracking, ablation algorithm, pulses, and depth; preablation and intraablation rotational activity were analyzed and evaluated using regression models.
Results
Preablation static iris recognition was successful in 247 eyes, without difference in flap creation methods (P = .6). Age (partial correlation, −0.16; P = .014), amount of pulses (partial correlation, 0.39; P = 1.6 × 10−8), and gender (P = .02) were significant predictive factors for the amount of intraoperative cyclodeviation. Tracking difficulties leading to linking the ablation with a new intraoperatively acquired iris image were more with femtosecond-assisted flaps (P = 2.8 × 10−7) and the amount of intraoperative cyclotorsion (P = .02). However, the number of cases having nonresolvable failure of intraoperative rotational tracking was similar in the 3 flap creation methods (P = .22).
Conclusions
Intraoperative cyclotorsional activity depends on the age, gender, and duration of ablation (pulses delivered). Femtosecond flaps do not seem to have a disadvantage over microkeratome flaps as far as iris recognition and success of intraoperative dynamic rotational tracking is concerned.
Dr Agarwal's Eye Hospital and Eye Research Centre, Chennai 600 086, India
Inquiries to Amar Agarwal, Dr Agarwal's Eye Hospital and Eye Research Centre, 19, Cathedral Road, Chennai 600 086, India
ABSTRACT