The Effect Of Palpebral Fissure Height In A Primary Gaze Position On Tear Film Stability

To determine the influence of palpebral fissure height in a primary gaze position on tear film stability in healthy individuals, according to age and gender. 

This cross-sectional study was performed in the Outpatient Department of Ophthalmology, University Hospital Center in Zagreb, Croatia.

A total of 120 adult subjects consecutively attending the Outpatient Ophthalmology Department for the standard eye examination during the two months were enrolled in the study, and divided according to age into two groups with an equal distribution of men and women. Subjects with ophthalmic pathology or other conditions and disorders that could influence the tear film stability were excluded from the study. Age of 50 was determined as an age limit. Both of the groups included 30 subjects with and without tear film dysfunction symptoms. Schein questionnaire was used in order to determine the presence of the tear film dysfunction symptoms. Ocular signs were assessed by TBUT and NIBUT.

Palpebral fissure height was significantly negatively correlated with TBUT values in both groups, younger (p<0.001) and older subjects (p=0.009) with more pronounced results among younger men (p=0,004) and women (p<0.001). The same, but statistically significant and weak negative correlation was found between palpebral fissure height and NIBUT values in both age groups. TBUT was better predictor of tear film instability (E. -2.53128).

This study showed the importance of evaluation of ocular surface area and exposed eye among healthy individuals. Enlarged exposed ocular surface due to higher palpebral fissure height in healthy individuals' primary gaze position negatively affects the function and tear film stability and alters the eye desiccation in both age groups. In conclusion, assessment and gradation of tear film dysfunction in routine clinical practice should be provided by easily available and practical tools.