The patient pool of dry eye sufferers is no longer restricted to older individuals and females, and new research has also shown that signs and symptoms of the disease vary among those affected. Looking into how DED affects different age groups, researchers from Taiwan recently reported that younger patients may have more symptoms and blink more often. They believe this could be caused by thinner lipid layer thickness, as the structure and function of these patients’ meibomian glands were less affected compared with middle-aged and older individuals.
The retrospective investigation enrolled 675 patients with DED who were divided into three age groups: ages 20 to 41, 41 to 60 and 60+ (n=143, 304 and 228, respectively). Testing included OSDI and SPEED questionnaires, Schirmer II scores, meibomian glands, lipid layer thicknesses and blink/incomplete blink rates.
Based on the SPEED and OSDI scores, the younger patients had higher subjective symptom severity. Additionally, the SPEED scores negatively correlated with lipid layer thickness in all age groups. One possible explanation of the increased severity of symptoms in younger patients is their larger corneal nerve density and lower pain threshold, the researchers suggested. Aging is associated with a decrease in corneal sub-basal nerve fiber density and an increase in pain thresholds, so younger patients may have higher corneal sensitivity, they explained.
Younger patients also had more functional meibomian glands and less glandular loss than the other age groups. They had thinner lipid layer thicknesses, a lower meiboscale and more expressible meibomian glands. Individuals who fell within this age range also had more total blinks and incomplete blinks as well as a higher incomplete blink rate.
Another possible contribution to the higher symptom scores in younger patients was their thinner lipid layer thickness, the investigators suggested. Incomplete blinks may lead to less squeezing of the meibomian glands by the orbicularis muscle, resulting in less effective meibum secretion, they explained. The resultant thin lipid layer thickness provides less protection against tear evaporation and may cause more severe symptoms and more frequent blinking, they said.
“Because the tear film characteristics and symptom severity are dissimilar among patients with DED of different age groups, treatment strategies may be tailored according to these parameters to achieve optimal outcomes, such as encouraging complete blinking in younger patients,” the researchers wrote in their paper.
Weng HY, Ho WT, Chiu CY, et al. Characteristics of tear film lipid layer in young dry eye patients. J Formos Med Assoc. 2020;S0929-6646(20):30526-X.