LYZ and Down syndrome: non-dry-eye disease) and; tear lysozyme concentration (mg/mL): Sjogren ́ssyndrome: 751.25 ± 244.73, meibomian gland dysfunction: 1423.67± 182.75, non-dry-eye disease: 1409.90 ± 188.21 (p<0.01Sjogren ́s syndrome vs. non-dry-eye disease and p<0.01 Sjogren ́s syndromevs.