Characteristics of tear film lipid layer in young dry eye patients

To investigate the characteristics of subjective symptoms and objective parameters among young patients with dry eye disease (DED) and compare them with those of older patients.

We retrospectively enrolled 675 patients with DED who were divided into three age groups (20-41 years [younger], 41-60 years [middle], and >60 years [older]) (n = 143, 304, and 228, respectively). Subjective symptoms were evaluated using Standardized Patient Evaluation of Eye Dryness (SPEED) and Ocular Surface Disease Index (OSDI) questionnaires. Aqueous tear secretion was evaluated with the Schirmer test II. The number of expressible meibomian glands was evaluated with a slit-lamp-aided standardized evaluator. Lipid layer thickness (LLT), blink/incomplete blink rates and meibography were measured with the LipiView® II interferometer. The extent of the meibomian gland dropout was graded using a meiboscale.

The younger age group had higher subjective symptom severity, as reflected by higher SPEED (p < 0.001) and OSDI scores (p = 0.051). The SPEED scores negatively correlated with LLT in all patients (r = -0.136, p < 0.001). Younger patients also had thinner average LLT (p < 0.001), lower meiboscale (p < 0.001) and a higher number of expressible meibomian glands (p < 0.001). Additionally, they had significantly more total blinks (p < 0.001), incomplete blinks (p < 0.001), and incomplete blink rate (p = 0.006).

Manifestations of DED vary with age. In our cohort, younger age patients had more symptoms and blinks, which may have resulted from thinner LLT as the structure and function of the meibomian glands were affected less than in middle and older age patients.