Visual perception of faces with unilateral and bilateral cleft lip and palate: An Eye-Tracking Study

To test the hypotheses that there are differences between orthodontists, individuals with cleft lip and palate (CLP) and laypersons in the visual perception of faces with unilateral (UCLP) and bilateral cleft lip and palate (BCLP), the faces with UCLP and BCLP are visually perceived differently and the hierarchy of visual attention changes when viewing individuals with CLP.

Department of Orthodontics and Experimental Psychology at Ege University, İzmir. Sixty images (faces with a social smile and at rest) of 30 volunteers (unaffected controls, UCLP, BCLP) were viewed by 80 participants: orthodontists, individuals with CLP and laypersons.

Eye fixations on four areas of interest were quantified: eyes, nose, upper lip and lower lip-chin. Time to first fixation, fixation before, fixation count and fixation duration parameters were analysed.

Orthodontists fixated on the upper-lip area more often than laypersons or individuals with CLP (F_2.144 =8.47, P=.00, η²=.19 in faces at rest). The upper-lip area received more fixations (F_2.144 =21.93, P=.00, η²=.23) and longer fixation durations (F_2.144 =28.86, P=.00, η²=.27) from all participants who gazed on faces with UCLP and a social smile.

The hypotheses of the study were supported. Orthodontists and laypersons focused more attention on the upper lip and eyes in the resting position, respectively. The upper-lip area of the BCLP images captured more attention at rest.