The Relationship Between Meibomian Gland Morphology, Dry Eye Disease, and Electronic Device Use in Pediatric Patients

Abstract

"Purpose: The purpose of this systematic study was to establish preliminary comparisons of various morphological and clinical parameters between dry eye and normal subjects in a pediatric cohort.

Methods: Children aged 5-17 were recruited for the study with no previous clinical diagnosis of dry eye disease (DED) or meibomian gland dysfunction (MGD). Diagnostic criteria for DED consisted of positive scoring on at least two of three components; subjective symptoms, abnormal tear function, and vital staining. All subjects completed SPEED questionnaires to assess dry eye symptoms; scores above 5 indicated positive symptomology. Tear film and ocular surface integrity were inspected using fluorescein and lissamine green dye with slit lamp miscroscopy. Corneal fluorescein, as well as temporal and nasal conjunctival lissamine green staining was graded from 1-4 (0=no staining; 4=coalesced). A staining score of more than 4 points across all 3 sections indicated positive vital staining. Abnormal tear function was defined by a TBUT ≤5s. Meibomian gland morphology, lipid layer thickness, and blink patterns were evaluated with the use of a Lipiview Interferometer. The 5-point meiboscale for gland atrophy was used for dropout grading, while tortuosity was defined by number of glands with ≥45° angles. Tear volume assessment was completed with phenol red test. Questionnaires administered to both the child and family member were used to assess electronic device usage in order to screen for possible associations with average daily screen time and aforementioned parameters.

Results: A total of 24 subjects participated in the study. Dry eye was found in 41.7% of the subjects. Presence of meibomian gland dropout and tortuosity were 70.8% and 87.5% respectively. Dropout was significantly higher in the dry eye group (p=0.016), although tortuosity was similar between both groups (p=0.93). Tear breakup times were significantly lower in the dry eye group (5.30s vs 9.66s; p<0.001) along with total staining scores (8.00 vs. 3.21; p=0.043). Blink behavior and measurements of lipid layer thickness (LLT) did not vary between the two groups; partial blink ratios were 0.62 and 0.67 for DED and normal groups respectively (p=0.76), and lipid layer thicknesses were 55.9nm and 57.43nm (p=0.84). Electronic device use did not vary significantly between the two groups (p=0.99). Screen time was significantly correlated with higher rate of partial blinks (r=0.84). Higher lipid layer thickness significantly predicted higher partial blink fraction in the left eye (p=0.39) and approached significance in the right eye (p=0.08).

Conclusion: The present study provides a current baseline data on ocular surface characteristics and meibomian gland anatomy in healthy children with clinically dry eye vs. those without dry eye. Our results indicate that MGD and DED are highly inter-related at a much earlier age than previously acknowledged, and that the significant rise in pediatric variations of DED represent a worthwhile cause for investigation into long-term risk factors for disease progression. Better understanding of baseline ocular surface and tear film characteristics will be crucial to identify the impact increasingly prevalent risk factors, such as visual device use, myopia interventions, and other changing environmental factors might have on the pediatric population."