Assessing the Fisher, Millard, and Mohler Techniques of Cleft Lip Repair Surgery with Eye Tracking Technology

Purpose: Cleft lip is one of the most common congenital anomalies in the world that can have severe consequences on a child’s social, functional, and emotional development. Eye-tracking technology offers an unbiased way to evaluate how viewers perceive the aesthetic outcome of cleft lip repairs. Here, we apply eye-tracking technology to compare how viewers with varying degrees of experience in plastic surgery assess the aesthetic quality of the Fisher, Millard, and Mohler cleft lip repair techniques.

Methods: 17 subjects with plastic surgery experience ranging from layperson to attending plastic surgeon were shown 20 images (5 controls without cleft lip and 5 each of unilateral Fisher, Millard, and Mohler repairs). Viewers were instructed to examine the images, while eye-tracking equipment was used to track viewers’ gazes and analyze the distribution of attention during the task. Subjects were then asked to evaluate the overall aesthetic quality of each image on a 1-to-10 Likert scale. Eye-tracking equipment and software from Tobii Technology (USA) was used to track raters’ gazes and analyze the number of gaze fixations and time of fixation on different areas on the displayed faces.

Results: On average, subjects demonstrated the highest number of gaze fixations for Fisher repairs (18.3), followed by Millard (16.8) and Mohler (15.8) repairs. Duration of time in fixed gaze followed a similar pattern, in which subjects looked longest at Fisher repairs (6.73 sec), followed by Millard (5.33 sec) and Mohler (5.30 sec) repairs. In evaluating the aesthetic quality of the three techniques, subjects also most preferred the Fisher repair (6.9), over the Millard (5.8) or the Mohler (6.5) repairs. The repair scar was the first area to catch viewers’ attention in only 4 out of 15 repairs (2 Fisher, 1 Millard, and 1 Mohler), but the area that held the longest duration of fixation on average in 6 out of 15 repairs (3 Fisher, 1 Millard, and 2 Mohler), as well as the area that garnered the highest number of fixations in 7 out of 15 repairs (4 Fisher, 1 Millard, and 2 Mohler).

Conclusions: Eye tracking provides a novel and objective way to evaluate viewers’ attention and to correlate gaze data with clinical aesthetic outcomes. In comparing the three techniques, the subjects’ attention indicated that they tend to prefer the Fisher repair, with these images receiving the highest number of fixations, longest time of fixation, and highest Likert score. Interestingly, viewers seem to first fixate on the philtrum to establish a reference of normal anatomy before moving to examine the repair scars, as none of the repair techniques typically caught viewers’ initial attention. However, viewers did tend to spend more time analyzing the scar than other areas of the face in about half of all repairs after first establishing a normal reference frame. This suggests that repair scars do capture viewers’ attention but only upon a closer inspection. Ongoing work includes testing these effects on craniofacial and non-craniofacial attending surgeons and exploring the impact of bilateral repairs of each technique.