Assessing Eye Movement Dynamics And Fixation Stability Between Eyes During Same-Session Bilateral Femtosecond Laser In Situ Keratomileusis

Published 2025 - 43rd Congress of the ESCRS

Reference: PP15.03 | Type: Free paper | DOI: 10.82333/v98f-z168

Authors: Hashem Abu Serhan* ¹ , Rafae Ali Khan ² , Zain Ul Abideen ³ , Ayesha Ayesha ⁴ , Lucas Mendes Barbosa ⁵ , Ro’a Abdulrahman Hussain Abo-Fares ⁶ , Hussam Akram ² , Areena Fatima ³

¹Department of Ophthalmology,Hamad Medical Corporation,Doha,Qatar, ²Riphah International University,Islamabad,Pakistan, ³Quaid-e-Azam Medical College,Bahawalpur,Pakistan, ⁴Shifa College of Medicine,Islamabad,Pakistan, ⁵Federal University of Minas Gerais,Belo Horizonte,Brazil, ⁶The Hashemite University,Zarqa,Jordan

Purpose

This study investigates eye movement dynamics during excimer laser ablation, specifically femtosecond laser-assisted in situ keratomileusis (FemtoLASIK). It compares movement patterns between the right eye (RE), mostly operated on first, and left eye (LE), operated on second, analyzing the direction, magnitude, and temporal changes of movement during the procedure.

Setting

American University of Beirut Medical Center, Beirut, Lebanon

Methods

A retrospective analysis was conducted on 92 eyes from 46 patients who underwent FemtoLASIK with the SCHWIND AMARIS system. Eye-tracking data were collected to record X and Y directional movements,

with variability assessed using standardized metrics such as mean and standard deviation (STD)

. Statistical analyses such as t-tests and Pearson correlations compared movement patterns between RE and LE. Temporal trends and variability were analyzed using split-interval and correlation methods to identify key changes during surgery.

Results

Eye movement patterns revealed greater variability in the Y-direction than in the X-direction for both first and second operated eyes. The second eye showed greater overall variability, particularly in the Y-direction, with earlier and more dynamic movement increases throughout surgery. X-direction movements were initially reduced for both eyes but gradually increased after 22 seconds. The Y-direction movements increased significantly after 13 seconds in the first eye and 5 seconds in the second eye.

Conclusions

Eye movements during excimer ablation in FemtoLASIK exhibit dynamic variability, especially in the Y-direction. The second operated eye showed earlier and more pronounced movements, mainly in the Y-direction, which intensified as the surgery progressed. These findings can potentially alter surgical planning and technical details laid out by surgeons and manufacturers, respectively.