Effect of ocular demodicosis on the stability of the tear film and the tear break up time

Abstract

The aim of the study was to analyze the correlation between the presence of Demodex mites in the hair follicles of patients' eyelashes and the stability and break up time of the tear film assessed with the Non-Invasive Tear Break Up Times (NIBUT) method. 319 patients were included in the study (195 women, 124 men). The patients were divided into two groups: those with Demodex infestation and without visible symptoms of eyelid or eye surface diseases, and asymptomatic non-infested patients. The NIBUT analysis was performed with a 5 M keratograph (oculus). Non-invasive tests were performed to identify the first and mean values of the tear break up time. The first and mean tear break up time in the Demodex-infested group was lower than in the non-infested subjects. The difference was a highly statistically significant. There was a significant correlation with the age of the patients for the first break up time. The first break up time in both eyes decreased with the age of the Demodex-infested and non-infested patients. The NIBUT analyses indicate the impact of Demodex mites on the tear film stability. This may suggest possible association of demodicosis with dry eye syndrome.

The correlation between Demodex infestation and meibomian gland dysfunction at different ages

“…In elderly Demodex-positive patients, CFS was more serious and FBUT was lower compared to negative patients. Sędzikowska et al showed that, in a study of patients without visible eyelid or eye surface disorders, the first and mean BUT in the Demodex-infested group was shorter than that in non-infected individuals [31].…”

“…In elderly Demodex -positive patients, CFS was more serious and FBUT was lower compared to negative patients. Sędzikowska et al showed that, in a study of patients without visible eyelid or eye surface disorders, the first and mean BUT in the Demodex -infested group was shorter than that in non-infected individuals [ 31 ]. Our results indicate a significant correlation between Demodex infestation and lower tear film stability and corneal epithelial injury in elderly patients.…”

“…Further, Cheng et al suggested that microstructural changes of MGs were positively related to Demodex infestation and proportional to the number of mites [ 16 ]. These consequences were associated with the tear film stability, followed by damage to the ocular surface epithelium [ 31 ]. Some studies have found correlation between Demodex infestation and imbalance in the bacterial microbiota in the conjunctival sac which can affect the functioning of the ocular surface [ 32 , 33 ].…”

The impact of ocular demodicosis on the eyes

“…Ocular demodicosis increases with age, and is associated with eyelid disorders including anterior blepharitis, meibomian gland dysfunction (MGD), chalazia, and blepharo-keratoconjunctivitis in both adult and pediatric populations [2,3]. Tear film instability [4,5], pterygium recurrence [6], and rosacea have been linked to Demodex. Blepharitis was the first reported to be associated with ocular demodicosis in 1959 [7].…”

“…Demodex folliculorum is more strongly associated with anterior blepharitis while Demodex brevis with MGD, recurrent chalazia, and refractory keratitis [2,8]. Demodex may reside as normal flora in healthy or asymptomatic diseased individuals [1,4] but become pathogenic when organism numbers reach a critical threshold, which are then sufficient to induce or exacerbate ocular symptoms. Higher numbers of Demodex have been noted in Demodex blepharitis (DB) compared to controls [2], however, the minimum number of Demodex required to induce symptoms remains unknown.…”