ABSTRACT
Purpose: To identify the facial anthropometric parameters that predict the difficulty during femtosecond (FS) laser. Methods: This was a single?center observational study was conducted on participants between the ages 18 and 30 years who were planned for FS?LASIK (femtosecond laser?assisted laser in situ keratomileusis) or SMILE (small incision lenticule extraction) at Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India. The front and side?facing images of the participants were analyzed using Image J software to measure different anthropometric parameters. The nasal bridge index, facial convexity, and other parameters were measured. The difficulty faced by the surgeon during docking was recorded for each subject. The data were analyzed on Stata 14. Results: A total of 97 subjects were included. The mean age was 24 (±7) years. Twenty?three (23.71%) subjects were females while the rest were males. Difficulty in docking was seen in 1 (4.34%) female and 14 (19%) males. The mean nasal bridge index was 92.58 (±4.01) in subjects with deep?set eyes and 89.72 (±4.30) in normal subjects. The mean total facial convexity was 129.28 (±4.24) in deep?set eyes, and 140.23 (±4.74) in normal subjects. Conclusion: Total facial convexity appeared as the most important feature, with the value being less than 133° in most subjects with unfavorable facial anthropometry