The Effect of Palpebral Fissure Height in Primary Gaze Position on Tear Film Stability

This study aimed to investigate the effect of palpebral fissure height in primary gaze position in healthy individuals on tear film stability. In this cross-sectional study, 120 subjects (60 male and female each) were enrolled and divided according to age into two groups, i.e., group 1 (aged 18-50 years) and group 2 (aged 51 and older). Palpebral fissure height on both eyes was measured in primary gaze position with a clear plastic ruler held in a central vertical position between the upper and lower lid margin, and the standard tear break-up time (TBUT) test was performed to evaluate tear film stability. Palpebral fissure height was significantly higher in younger than older subjects in all measurements on both eyes (p<0.001), and TBUT was shorter in older than in younger subjects. In all subjects included in the study, palpebral fissure height was not related to TBUT (p=0.589). However, analyzing the two age groups separately, a significant negative correlation was found between the palpebral fissure height and TBUT in both groups of younger (p<0.001) and older (p=0.009) subjects. In conclusion, an enlarged exposed ocular surface due to higher palpebral fissure height in healthy individual’s primary gaze position negatively affects tear film stability expressed by TBUT.
Cilj ovog istraživanja bio je ispitati utjecaj visine vjeđnog rasporka u primarnom položaju pogleda kod zdravih osoba na stabilnost suznog filma. U ovo presječno istraživanje bilo je uključeno 120 ispitanika (60 muškaraca i 60 žena) i prema životnoj dobi podijeljeno u dvije ispitivane skupine: 1. skupina (u dobi od 18-50 godina) i 2. skupina (u dobi od 51 i više godina). Visina vjeđnog rasporka na oba oka mjerena je u primarnom položaju pogleda prozirnim plastičnim ravnalom koje se držalo u središnjoj okomitoj liniji između ruba gornje i ruba donje vjeđe, a standardni test pucanja suznog filma (tear break-up time, TBUT) primijenjen je za procjenu stabilnosti suznog filma. Visina vjeđnog rasporka bila je u svim mjerenjima na oba oka značajno veća u mlađih nego u starijih ispitanika (p<0,001), a TBUT je bio kraći u starijih nego u mlađih ispitanika. U svih ispitanika uključenih u istraživanje visina vjeđnog rasporka nije bila povezana s TBUT-om (p=0,589). No, analizirajući dvije dobne skupine odvojeno utvrđena je značajna negativna povezanost između visine vjeđnog rasporka i TBUT-a u obje skupine, u mlađih (p<0,001) i starijih (p=0,009) ispitanika. U zaključku, povećana izložena očna površina zbog veće visine vjeđnog rasporka u primarnom položaju pogleda u zdravih osoba negativno utječe na stabilnost suznog filma izraženu TBUT-om.