Table 2.
Pertinent studies assessing ocular surface and tear film characteristics with the use of face masks.
| Authors (Country) | Population | Examinations | Observations |
|---|---|---|---|
| Marta et al. (Portugal) | General population (pre- and post-pandemic, n = 274) | NITBUT, lipid layer thickness, blink rate, Schirmer test, tear meniscus height, tear osmolarity and meibography | In the face mask use period, blink rate, tear menisucus height, tear osmolarity and loss area of the meibomian glands were worse; mean lipid layer thickness and Schirmer test were better and NITBUT was similar. |
| Tangmonkongvoragul et al. (Thailand) | Medicine students (n = 528) | Lipid layer thickness, meibography and blinking pattern. | Severe DED patients were likely to have higher meibomian gland tortuosity (not statistically significant) |
| Shalaby et al. (Egypt) | Healthy subjects (n = 200: 100 surgical mask and 100 N95) | TBUT, Schirmer test I, corneal fluorescein staining before and after 1-h face mask use | All tear film parameters worsened significantly in both groups. Changes were larger with surgical masks compared to N95. There was a strong positive correlation between the daily number of hours spent wearing a facemask and corneal staining. |
| Alanazi et al. (Saudi Arabia) | Healthy subjects (n = 54) and controls (no mask use; n = 50) | NITBUT, phenol red thread and tear ferning tests before wearing a face mask and immediately after its removal after 1 h use | Significant differences were found between the NITBUT measurements, before and after wearing a face mask. No differences were found in the phenol red thread and tear ferning tests scores. |
| Bilici et al. (Turkey) | Health-care professionals (n = 74) | NITBUT morning and afternoon | Mean NITBUT after 8 h was lower than baseline (p < 0.0001) |
| Azzam et al. (Israel) | Health-care professionals (surgical masks n = 30; N95 n = 30) | TBUT, corneal and conjunctival staining and meibography | Both masks caused dryness according to TBUT and Meibomian glandular loss. N95 mask caused significantly more dryness according to TBUT. |
| Aksoy et al. (Turkey) | General population (n = 52) | Schirmer test I, TBUT and corneal staining at initial admission (T1), after 8 h of face mask use (T2), after 15 days of >8 h daily wear of face masks with taping (T3) | Mean TBUT was 13.03 ± 2.18 at T1, 9.12 ± 1.85 at T2, and 12.78 ± 2.05 s at T3. There was a significant difference between T1 and T2, and between T2 and T3 in TBUT, Schirmer-1, and corneal staining. |
| Esen Baris et al. (Turkey) | Healthy health care professionals (n = 33) | NITBUT | Mean TBUT was 9.3 ± 1.0 (3–16) seconds at 8 a.m. and 8.3 ± 1.5 (3–14) seconds at 5 p.m. (p = 0.01). Use of a surgical mask for the entire work-day worsened TBUT |
| Giannaccare et al. (Italy) | Healthy subjects (university students; n = 20) | NITBUT, tear meniscus height, ocular redness and meibography before and after 8 h of face mask wearing | With face masks, tear meniscus height decreased significantly. Mean values of NITBUT, redness score and meibomian gland dropout did not change significantly. |
| Kapelushnik et al. (Israel) | Healthy subjects (n = 31) | Thermal images breathing normally with a surgical face mask | Ocular surface temperature was higher during expirium. The upper eyelid margin had the greatest temperature change. Sex, age, room temperature or body temperature had no effect. With taping, measurements were significantly lower in all regions compared to expirium without taping. No differences were observed in inspiration with and without taping. |
| D'Souza et al. (India) | Healthy subjects (practicing ophthalmologists; n = 17) | Schirmer test I, TBUT, tear film interferometry, OSI, corneal and conjunctival staining, concentration of proteins in tear samples and immune cell profile at two time-points (pre-face-mask-wearing period and post-face-mask-wearing period) | No significant changes in TBUT, Schirmer test I and OSI were observed post-face mask. Differences in some inflammatory markers. Higher proportions of leukocytes and natural killer T cells and a significant reduction in the proportions of eosinophils, B cells and plasma cells. |
| Arriola-Villalobos et al. (Spain) | Moderate-to-severe DED patients (n = 31) | NITBUT with a face-mask and after 10 min without a mask | First and average NITBUT increased without face masks |
| Mastropasqua et al. (Italy) | DED patients (n = 66) and healthy subjects (n = 62) | TBUT, Schirmer test I, corneal staining, confocal microscopy (corneal dendritic and goblet cell density), and impression citology (HLA-DR): baseline and 3 months. | After 3 months, Schirmer test worsened in DED patients. In controls, BUT and staining worsened only in >6 h face mask use. Dendritic cell density increased in DED patients and HLA-DR in controls with >3 h use |
DED: dry eye disease, NITBUT: non-invasive tear break-up time; TBUT: tear break-up time; OSI: objective scatter index.