A Comprehensive Ocular Surface Evaluation in a Portuguese Pediatric Cohort

Abstract

INTRODUCTION: Few studies have been published regarding dry eye disease (DED) in the pediatric age group and all have been performed outside of the European setting, where genetic and environmental factors may be different. Moreover, the analysis of the ocular surface and, consequently, the diagnosis of DED is progressing towards objective and standardized methods. Our purpose was to quantitatively describe the ocular surface in the Portuguese pediatric population and how it is influenced by the use of screen devices, eye rubbing and sleeping habits. Moreover, we aim to form a plain language summary that can be given to children and their parents for advice.

METHODS: Cross-sectional study that included healthy subjects aged 8 to 18 years. Exclu- sion criteria were systemic disorders or treatments known to affect the eye, any ocular or palpebral disease (such as diagnosed DED, meibomian gland disease or conjunctivitis, but not refractive error), use of contact lenses or any kind of eye drops. Subjects underwent: a customized survey together with the validated OSDI-6 questionnaire; IDRA® Ocular Surface Analyzer; tear osmolarity; basal tear secretion test with Schirmer strips (BTS), after instillation of topical anesthetic; and slip lamp evaluation of corneal fluorescein staining (CFS).

RESULTS: For analysis, 142 eyes of 72 subjects, with mean age 14.2 ± 2.6 [8.8-18.6] years, were included. Symptoms of DED were present in 35%: itching was the most frequent symptom (30%), followed by tearing (9%) and discomfort or dryness (7%). The OSDI-6 score was suggestive of dry eye in 54%. Any degree of CFS was present in 51% and formal DED diagnosis according to TFOS II criteria in 49%. CFS was not associated with symptoms (p=0.063) and 46% of subjects without symptoms still had some degree of CFS. There was negative correlation between on-screen time and eye blink quality score (EB, r=-0.218; p=0.009), BTS (r=-0.255; p=0.002) and non-invasive break-up time (NIBUT, r=-0.169; p=0.045), even after considering possible confounders. The presence of CFS was associated with higher on-screen time (6.8 vs 5.6 hours per day, p=0.015). Better eye blinking quality was observed in subjects that reported symptoms (p<0.001). Basal tear secre- tion was reduced in eyes with CFS (p<0.001), but there were no differences in osmolarity, NIBUT, EB, lipid layer thickness, loss area of meibomian glands or tear meniscus heigh (p>0.110). There were no differences regarding eye rubbing or sleeping habits (p>0.098).

CONCLUSION: In a healthy pediatric cohort, the prevalence of DED was around 50%. Blinking, tear production and tear stability may be affected by the overuse of screen devices. The functional integrity of the ocular surface depends on the blinking reflex, which appears to be mostly defective in individuals without symptoms and probably impaired somaesthesia. The incorporation of symptomatology in the diagnosis of DED should be carefully reconsidered in this age group, as it may not be necessarily pathological. Many may show signs of disease without symptoms which in turn aggravates blinking dynamics and may impair a proper neurotrophic response. From a practical standpoint and in plain text, children can be advised that too much screen time may continuously affect their eyes, regardless of complains.