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. Author manuscript; available in PMC: 2025 Nov 1.
Published in final edited form as: Semin Ophthalmol. 2024 Apr 17;40(4):306–319. doi: 10.1080/08820538.2024.2332355

Tear Film Dynamics in Visual Display Terminal Users: A Review of Impact on Goblet Cells, Lacrimal and Meibomian Gland Function

Moumi Maity a, Anat Galor b,c, Sayan Basu d,e, Swati Singh d,✉
PMCID: PMC7616525  EMSID: EMS196860  PMID: 38629642

Abstract

Purpose

The prevalence of dry eye disease (DED) is rising among visual display terminal (VDT) users, a trend that correlates with the growing use of digital devices. The prevalence of VDT-associated DED is reported based on dry eye questionnaires; however, VDT’s impact on tear film parameters is less understood.

Methods

A review of published literature on both the alterations in tear film observed in VDT users and the impact of various interventions on their tear film.

Results

Most studies show reduction in tear stability as well as reduction in the blink rate. The role of lacrimal gland hypofunction in visual display terminal (VDT) users is a subject of ongoing debate. Schirmer test values typically exceed the 10 mm threshold, suggesting normal tear production, and tear osmolarity remains within normal ranges but VDT users consistently present with lower Schirmer values compared to non-VDT users. The effects on Meibomian glands and mucin levels need more research as the numbers studied are small. Very few studies have analysed mucin levels in VDT users with reports of normal or reduced values. Even asymptomatic users can have tear film instability; hence, the diagnostic criteria need to be formulated and validated. Different interventions such as neurostimulation, blink improving apps, eyelid warming devices, moist goggles, and lubricants have been explored in VDT users but without a control arm and in asymptomatic VDT users in most studies.

Conclusion

The alterations have been observed on aqueous, lipid and mucin components of the tear film, although the extent of the impact is variable across studies. There is urgent need of well-designed studies for studying the tear film changes and management options for the upcoming lifestyle epidemic in VDT users.

Keywords: Dry eye disease, lacrimal gland, tear break-up time, tear film, visual display terminal

Introduction

Visual display terminal (VDT) use has garnered significant attention in relation to dry eye disease (DED) due to the technological boom and the escalated daily consumption of digital media. Several cross-sectional population-based studies have established an association between digital screen use and DED.1–3 A meta-analysis estimated that the prevalence of DED among VDT users ranges from 9.5% to 87.5%.1 Many studies rely on DED symptoms and a single sign of tear film instability as a marker for VDT-associated DED.3–23 One of the initiators of the tear film disturbance is reduced blink rate, which reduces by 60% with VDT use from a resting state.3 The published literature shows huge variation in the extent of tear film changes, tear dynamics with smartphone or computer use, and the impact of interventions on tear film of VDT users.1,3–5,5–38 Most studies have focused on subjective symptomatology rather than objective tear film changes. The different underlying proposed mechanisms for VDT associated DED include tear instability, lacrimal hypofunction, meibomian gland dysfunction, and reduced mucin levels. Blink rate, blink amplitude, and tear film stability are compromised significantly during the dynamic VDT task, suggesting the evaporative DED to be the main driving force. However, few studies have postulated lacrimal hypofunction as a mechanism behind VDT-associated DED. In order to understand VDT-DED pathogenesis and possible steps for prevention/treatment, we need to understand and build a consensus on pathophysiological changes that occur at the ocular surface of VDT users. There are many unanswered questions, like why only some users develop symptoms despite similar exposure hours, whether VDT-associated DED is an aqueous, lipid or mucin deficient DED, if inflammation is a contributor to DED symptoms like in other forms of DED, and whether multiple mechanisms contribute to a cascade of changes driven by divergent pathologies. Also, understanding the impact of different treatments like neurostimulation, blink improving apps, eyelid hygiene and ocular lubricants on tear film of VDT users would help in formulating management options for these patients. In order to explore the above questions, the current review focused on the tear film changes reported in VDT users and selectively analysed studies that performed invasive or non-invasive tear film examinations in VDT users as well as explored the impact of interventions on tear film of VDT users.

Methods

Articles were searched from Google Scholar and PubMed using key terms “Tear film AND visual display terminal”, “Tear film AND computer vision syndrome’, “Dry eye and visual display terminal”, “Tear film and screen time”, “Tear film AND digital devices” and “Ocular surface AND digital devices”. All searches were limited to the English language, and abstracts of articles were reviewed for the mention of tear film examination. The flow chart in Figure 1 summarizes the details of excluded articles. Full text of 39 articles were reviewed, and key findings are summarized in Figure 2, and Tables 1 & 2.

Figure 1. Flow chart showing the search strategy for included articles.

Figure 1

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Figure 2. Schematic showing the reported effects of VDT use on different component of tear film.

Figure 2

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Table 1. Summary of articles describing the tear film parameters in VDT users along with duration of VDT use.

Article Number of Subjects Avg. Hours of VDT use/ day TBUT NIBUT Blink rate per min Schirmer test/TMH/ goblet cell density Corneal stain grade Other Comments
Patel et al.8 10 (VDT users and Non-VDT users) NA 17.5 ± 7.1 vs 17.2 ± 5.9 NA NA TMH: 0.25 ± 0.05 vs 0.16 ± 0.07 NA Similar tear film stability and tear volume in VDT users & non-users.
Nakamura et al.32 1025 VDT users 5.1 ± 2.7 NA 5.7 ± 2.7 NA 19.7 ± 10.2 NA
Cardona et al.24 25 healthy VDT users (Baseline, playing computer games with high and low rates of visual information) NA 26.8 vs 19.3 vs 22.8 (p < .001) 16.2 vs 11.5 vs 13.1 (p < .001) 20 vs. 8 vs. 12 (p < .001) TMH: 0.33 vs 0.27 vs 0.28 (p < .001) NA
Kojima et al.37 1 day disposable CL users:18, Two week frequent-replacement CL users:18, One month CL users:15 and RGP CL users:14; Non-CL wearers (102) 8.5 ± 3.5 vs 5.6 ± 2.2 vs 7.3 ± 1.7 vs 7.5 ± 1.0 vs 6.0 ± 1.2 (p = .03) NA 4.7 ± 2.0 vs 5.1 ± 2.4 vs 3.6 ± 1.7 vs 4.7 ± 1.8 (CL 4.1 ± 1.9 vs Non-CL 5 ± 2.9) (p = .55) NA 13.7 ± 11.8 vs 16.9 ± 11.3 vs 15 ± 10.4 vs 14.3 ± 11.9 (12.3 ± 9.5 vs 14.7 ± 10.9) (p = .66) TMH: 0.53 ± 0.19 vs 0.71 ± 0.33 vs 0.59 ± 0.26 vs 0.57 ± 0.22 (0.58 ± 0.31 vs 0.69 ± 0.34) (p = .36) 1.8 ± 1.9 vs 1.8 ± 2.6 vs 2.2 ± 1.6 vs 1.6 ± 1.7 (p = .68) No difference in tear film parameters between CL and non-CL VDT users.
Moon et al.9 28 symptomatic VDT users 260 healthy VDT users 2.4 ± 0.96 vs 1.8 ± 0.8 (p = .001) NA 7.4 ± 1.3 vs 9.2 ± 1.4 (p < .001) NA NA NA Smartphone use is a major risk factor for DED
Wu et al.31 Symptomatic VDT users-Long-time (53) Short-time1 8.3 ± 2.3 vs 3.2 ± 0.9 (p < .0001) NA 4.9 ± 2.4 vs 6.7 ± 2.7 (p < .001) Meiboscore 2.3 ± 1.1 vs 1.4 ± 0.8 (p < .0001) NA 11.5 ± 8.3 vs 12.9 ± 9.7 (p > .05) 3.7 ± 2.98 vs 1.5 ± 1.7 (p = .55)
Bhargava et al.35 344 VDT users
371 non-VDT users		 3–10 h NA 11.26 ± 1.68 vs 15.68 ± 2.62 (p < .001) NA 24.6 ± 8.6 vs 32.8 ± 7.7 (p < .001) NA
Uchino et al.39 96 symptomatic VDT users NA 3.8 + 2.4 NA NA Goblet cell density: 976 vs. 1576 (p < .001) 19.4 ± 12.4 Tear MUC5AC= 3.5 ± 3.2 ng/mg in DED vs. 8.2 + 10.4 ng/mg non-DED 0.7 ± 1.9 Human tear film stability and low MUC5AC concentrations in VDT users.
Moon et al.41 60 symptomatic VDT users 856 asymptomatic VDT users Smartphone use 3.18 vs 0.62 (p < .001), Computer use 1.10 vs 0.76 (p < .001) NA 9.2 ± 1.9 vs 10 ± 3.25 (p < .001) NA NA NA
Uchino et al.3 858 office workers Gp.1–680 (IBI>TBUT) Gp.2-178 (IBI<TBUT) NA; 56% >8 hours use NA 3.7 ± 2.6 vs 5.7 ± 2.7s (p < .001) 7.6 ± 7.0 vs 22.7 ± 9.8 (p < .001) 17.5 ± 11.6 vs 21.1 ± 11.5 (p < .001) No difference
Cortes et al.10 120 asymptomatic VDT workers NA 6.8 ± 3.5 NA NA 13.4 ± 1.3 NA
Rossi et al. 2018 DED confirmed-32 DED Suspect-92 DED Absent-70 7.3 ± 1.9 vs 5 ± 2.9 vs 4.6 ± 2.7 (p < .001) NA 6.8 ± 2 vs 7.7 ± 1.5 vs 11.7 ± 1.8 (p < .001) NA NA 30% vs 2% vs 0% with positive staining Long-time VDT use associated with decreased TBUT (p < .001), but not with changes in CFS (p = .81)
Prabhasawat et al.11 30 healthy VDT users (e-book vs. printed book reading for 20 min) NA 10.2-> 8.5 (p < .001) vs 10.8-> 9.2(p = .006) 6.9-> 4.4 (p < .001) vs 5.7-> 5.6 (p = .04) NA 21.8 ± 9.7 TMH: [0.22-> 0.21 (p =.1) vs 0.23-> 0.23 (p = .94)] 0-> 0 (p = 1) vs 0-> 0 (p = 1.0)
Tichenor et al.12 Symptomatic VDT users Group 1 (8–10 years of age) = 83
Group 2(11–13 years) = 81
Group 3 (14–17 years) = 61		 NA NA 9.2 ± 7.2 vs 9 ± 6.4 vs 9.9 ± 7.4 (p = .74) NA TMH: 0.19 ± 0.07 vs 0.22 ± 0.08 vs 0.25 ± 0.09 0.18 ± 0.6 vs 0.16 ± 0.5 vs 0.21 ± 0.5
Yamanishi et al.33 Symptomatic VDT users: 329 Asymptomatic VDT users: 232 8.1 ± 2.3 vs 7.6 ± 2.1 (p = .1) 2.9 ± 1.0 vs 5.6 ± 3.0 (p < .001) NA NA 19 ± 11.5 vs 18.2 ± 12 (p = .39) NA
Valerio et al.13 Asymptomatic VDT users: 22 Symptomatic VDT users: 86 5.96 ± 2.5 h/d 6.8 ± 2.1 vs 5.7 ± 1.9 (p < .03) NA NA 17.7 ± 9.7 vs 12.97 ± 7.6 (p = .03) 1.2 ± 1.2 vs 1.2 ± 1.5 (p = .83)
Natalia et al.15 238 VDT users (at least more than 2 hours/day) >6 hours NA RE:9.9 ± 4.4 LE:13.02 ± 7.9 (p = .17) NA RE:13.02 ± 7.9 LE:12.97 ± 8.1 (p = .19) BE:Grade 0 (p = .47)
Duan et al.16 Symptomatic VDT users: 53 Asymptomatic VDT users: 26 8.08 vs 8.18 (p  = .52) NA 3.00 vs 12.00 (p < .001) NA TMH- 0.20 vs 0.24 (p = .11) NA MUC 1, MUC 16 and MUC 20 mRNA levels in VDT users were less than normal
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VDT= Visual display terminal; TMH= Tear meniscus height; NIBUT= Non-invasive break-up time; TBUT= Tear break up time; DED= Dry eye disease; CL= Contact lens.

Table 2. Summary of articles describing the changes in tear film parameters following VDT task or treatment for VDT-associated dry eye disease.

Article Type of study Number of Subjects (intervention/VDT task) Avg. Hours of VDT use/ day Change in TBUT (in sec) Change in NIBUT (in sec) Change in blink rate per min Change in Schirmer test/TMH/goblet cell density Corneal staining grade Comments
Author/year Study design Enrolled subjects Avg. Hours of VDT use/ day TBUT NIBUT Blink rate per min Schirmer test/TMH/ goblet cell density Corneal stain grade Other Comments
Hirota et al.4 Prospective (VDT task) 32 healthy VDT users (After 15 mins, 30 mins, 45 mins, and 60 mins of VDT use) NA NA 5.8 ± 3.4-> 4.3 ± 2.6-> 7.4 ± 3.3-> 5.1 ± 3.2 Complete: 6.7 ± 0.8-> 5 ± 0.7-> 7.5 ± 0.9-> 4.7 ± 1 Incomplete: 4.4 ± 1.1-> 4.9 ± 0.8-> 2.8 ± 0.9-> 5.5 ± 1 NA NA Total blink rate decreases with VDT use. An increase in incomplete blink rate contributes to tear film instability.
Yazici et al.18 Prospective (VDT task) Computer users: 51 Controls: 26 (before and after full day office work) 6.9 ± 2.7 vs 0.4 ± 0.5 0.7(p = .02) vs 0.8(p = .20) NA NA 2.1(p = .03) vs 0.0 (p = .66) Tear osmolarity 5 (p = .03) vs. 1.9 mosm/ L(p = .4) NA Occupational computer use significantly increased osmolarity and decreased TBUT and Schirmer scores.
Kim et al.19 Prospective (VDT task) 59 Healthy volunteers- one hour of tablet use 2 NA 0.5 (p = .003) NA NA NA Visual fatigue and discomfort were significantly induced by smart mobile device use.
Choi et al.20 Prospective (VDT task) 80 volunteers
50- smartphone 30- computer use for 1 hour and 4 hours		 NA 0.3->0.7 ↓ (<0.05) vs 0.6->0.3 ↑ (p <.05) 0.4->1.4 (p < .05) vs 1.9-> 1.8 ↓ (p <.05) NA   0.6->0.4 (p > .05) vs 0.7->1.4 TMH: 0.02->0.02 vs 0.03-<0.03 ↑ NA Smartphone use makes tear film unstable and increases oxidative stress at ocular surface.
Golebiowski et al.22 Prospective (VDT task) 12 healthy VDT users (Task: 60 min reading from smartphone) NA NA 0.4 (p = .73) 6 blinks per 1 min and 15 blinks per 60 mins TMH: 0.25(0.2–0.8) LLT: 3.5(1.5–5.5) NA No changes in NIKBUT, lipid layer and tear meniscus height.
Wang et al.17 Prospective (VDT task) 60 healthy smartphone users (Task: reading from smartphone) 8.2 ± 2.3 NA 32.5% vs.59.2% (% less than 5s) (p ≤ .0001) NA No change in Schirmer & MG expressibility NA High-intensity use of smartphones reduces tear film stability.
Srivastav et al.21 Prospective (VDT task) Group 1: 35 (Symptomatic) Group 2: 35 (Asymtomatic) One hour of laptop use 11.4 ± 3.2 vs. 2.3 ± 2.3 NA 4 ± 0.6 (p = .007) vs 1.05 ± 0.67 (p = .14) 2.4 ± 0.4 (p = .006) vs −1 ± 0.5 (p = .07) 1.4 (p = .14) vs 0.9 (p = 0) TMH: 0.001 vs −0.005 (p = .41) Tear osm- 1.5 vs. 0.9 (p = 0) NA
Hirayama et al.27 Prospective, controlled 20 (With and Without moist environment exposure for 4 hours/day for 5 days) NA 0.9 (p = .0032) vs 0.2 (p = .31) NA 3.4 (p = .44) vs 6.7(p = .05) NA 0.5 (p = .083) vs 0.4 (p = .30) A new moist air device increased blink rate and tear stability.
Kiok Ang et al.5 Prospective, controlled 26 (CLEAR: VDT task with a transparent plastic sheet vs. wink glass use for 20 min) 5.4 ± 2.1 vs 6.3 ± 2.8 NA 1.2 (p = .01) vs 0.3 (p = .50) 9 vs 15 (p = .001; during task) NA NA Wink glasses increases blink rate during short-term VDU use in healthy adults.
Bhargava et al.35 Prospective, randomized double-blind 256 symptomatic VDT users (omega 3 group and placebo group) for 45 days NA 0.2 vs. 0.2 (p = .84) NA NA 0.3 vs. 0.1 (p = .88) NA
Ren et al.25 Prospective self-control 22 symptomatic VDT users (Warming goggles use vs. 0.1% SH eye drop) 5 min, 30 mins, and 60 mins compared to baseline] 4 NA 9.4 vs. 1.9 (p < .001); 3.9 vs. 2.1 (p = .23); 3.2 vs.0.3 (p = .01) NA TMH 0.02 vs. 0.03 (p = .64); 0.03 vs.0.01 (p = .34); 0.02 vs. 0.0 (p = .52) NA Warming goggles use for one hour improved tear film better than lubricant use.
Vaz et al.34 Prospective, controlled Group A: 34 < 2 hours of VDT use
Group B: 43 > 2 hours of VDT use, 0.1% SH eye drops Task: videogaming 3 days)		 NA NA 7% vs. 5.8% low NIBUT (Group A; p = .06) 42% vs. 0% (Group B, p < .0001) NA No change in group A (p = .08) vs. Improved Schirmer in group B (p = .005) NA
Kawashima et al.6 Prospective, randomized double-blind H2 producing milk group: 27 Placebo group:27 for 3 weeks NA NA 4.28 vs 4.26 (p = .93) NA 9.41vs 11.52 (p = .73) NA
Sun et al.26 Prospective, controlled 22 symptomatic VDT users (Eyelid warming mask for 2 weeks) Control: 23 VDT users (plain mask for 2 weeks) NA 1.1 (p = .02); 0.8 (p = .003) Meibum expressibility improved by mean 0.7 (p = .05) NA NA NA NA Eyelid warming device improved tear stability and meibum expressibility
Estarelles et al.40 Prospective, controlled 31 healthy (15 mins reading on computer, tablet, e-reader and smartphone) (without and with artificial tear) NA NA 11,50->13.28 vs 14.02-> 12.57 vs 12.60-> 13.94 vs 12.62-> 12.04
(p = .01)		 0.75-> 0.69 vs 0.7->0.65 vs 0.7-> 0.7 vs 0.6-> 0.65
(p = .02)		 27.9-> 34.5 vs 36.7-> 40.08 vs 36.9-> 38.6 vs 39.6-> 33.2
(p = .03) TMH: 0.26-> 0.35 vs 0.30-< 0.33 vs 0.31-> 0.33 vs 0.30-> 0.33 (p<.0001)		 NA No statistical improvement in tear film parameters observed with artificial tears
Rajendraprasad et al.36 Prospective, randomized, open-label trial Group A (CMC 0.5%; N = 90) Group B (HPMC 0.3%; N  = 90) (Day 30, Day:90) NA 4.6 vs. 4.4 (p = .393 at day 30) -> 5.6 vs 5.7 ↑ (p = .4 at day 90) NA NA 9.9 vs. 8.7 (p = .04) at 90 days NA Carboxymethyl cellulose and hydroxypropyl methylcellulose equally effective
Ashwini et al.7 Prospective, randomized controlled, single-blinded 46 VDT users (blink software use for 15 days] (Intervention group:23 and controls: 23) ≥4h 1.0 vs. 0.0 (p = .07) NA (observed)-9 vs 9 (p = .66) -> 10 vs 10 (p = .79) (recorded)-6 vs 7.0 ((p = .47) -> 9 vs 9 (p = .83) NA NA “Blink-blink” software with 8 reminders/minute improved blink rate
Zeng et al.29 Prospective, self-controlled 17 healthy VDT users, TENS thrice/week (3rd TENS-> 6 th TENS) for 2 weeks NA 2.7 (p = .30)-> 4.2 (p = .02) NA NA TMH 0.6 (p = .03) -> 0.05 (p = .03) NA Periorbital TENS effectively improves tear film stability by eliciting strong blinks in healthy VDT users.
Estarelles et al.30 Prospective, longitudinal, controlled 29 Symptomatic VDT users (Computer task with and without two weeks of 20-20-20 rule) 12 ± 3 NA 0.15 vs. 0.19 ↓ (p = .99) 0 ± 44–16 -> 9 ± 53–19 TMH 0.0 vs. 0.01 (p = .54) LLT:0 vs. 0 (p = .18) 0 vs. 0 (p = .92) The 20-20-20 rule is an effective strategy for reducing dry eye symptoms
Cristian et al.39 Prospective 34 healthy VDT users (Computer, computer + CL, computer + CL + AT, smartphone, smartphone + CL and smartphone +CL + AT) NA 2.7 vs 1.2 vs 0.6 vs 1.4 vs 0.3 vs 1.5 (p = .01) NA NA TMH: 0.06 vs 0.01 vs 0.04 vs 0.03 vs 0.02 vs 0.04 (p = .004) NA Instillation of artificial tears are effective for reducing the effects of CL wearers using the display.
Fernando et al.34 Prospective, controlled 30 Study group (0.15% SH eye drops) 26 controls (Task: play videogame >6 hours for 3 days) 24.6 ± 14.7 h/week vs. 25.5 ± 20.6 h/ week (p = .84) 1.1 (p = .07, SH group); 0.3 (p = .10, control) NA NA 1.1 (p = .53); 1.5 (p = .45) 0.0 (p = .8) 0.1 (p = .26)
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VDT = Visual display terminal; TMH = Tear meniscus height; NIBUT = Non-invasive break-up time; TBUT = Tear break up time; DED = Dry eye disease; TENS = Transcutaneous electric nerve stimulation; SH = Sodium hyaluronate; LLT = Lipid layer thickness.

Results

Tear Film Break-Up Time

The tear film has been found to be unstable in VDT users with DED. Tear film stability has been measured invasively with sodium fluorescein dye and non-invasively with tear interferometry across VDT studies. Both invasive and non-invasive tear break-up time (TBUT) values have been noted to be reduced in VDT users. Across studies, mean invasive TBUT values range from 2.7 to 11.3s, and mean NIBUT values ranged from 2.9 to 10.7s in VDT at baseline, that is, prior to being given a VDT task.3,8,9,11–13,15,16,24,30,32,34 Only a few studies compared baseline invasive TBUT values between VDT users and non-users and found minor differences (0.8, 0.3s) between the groups, with VDT users having slightly more rapid break up times.8,18 Differences between groups were more robust when examining NIBUT values (mean difference 1.8 and 4.4s), with lower values in VDT versus non-VDT users.9,34 However not all studies have been uniform in this regard. One study found similar invasive TBUT values in users and non-users, though the sample size was small (N = 10).8 Differences in TBUT values have been noted between symptomatic and asymptomatic VDT users. Symptomatic VDT uses, on average, had lower TBUT values (range 3 to 9s lower) than asymptomatic users.9,13,16,21,32 Time of VDT use, however, did not seem to drive the noted TBUT reductions, as there were mostly similar between symptomatic and asymptomatic users, mean 5.9 h in one study13 and 8 hours in another.16

Baseline TBUT values have been found to decrease after computer or smartphone tasks in VDT users.4,21,22,24 Interestingly, the noted reduction was only significant in symptomatic, but not asymptomatic, VDT users. TBUT has been found, on average, to decrease 0.5 to 4s in symptomatic users, but only from 0.4 to one second in asymptomatic VDT users.18,20–22 VDT tasks given in studies varied, with some examples being one to four hours of laptop use, video game play, smartphone use, or a full day of office work. Interestingly, device type did not seem to impact change in TBUT values.17–20 However, the visual speed of the task variably affected tear stability.26 Specifically, computer games with high rates of visual information reduced stability to a greater degree than computer games with low rates of visual information. Hours of VDT use did impact tear stability and severity of dry eye symptoms across studies (Table 1), with increasing hours of use associated with more robust TBUT reductions. A large-scale population-based Japanese study of 102,582 middle-aged participants (aged 40 to 74 years) revealed the prevalence of dry eye to be higher in >5 hours (22.3%) daily VDT use than in < 1 hour (16.1%) daily VDT use3 irrespective of sex. Similar results were noted when examining the data in a binary fashion, as intensive (>6 hours/day) use of digital devices significantly increased the odds of poor tear stability.15 Finally, accumulated exposure time inversely correlated with TBUT,13,14,30 with long- term symptomatic VDT users having lower TBUT than short-term users (mean TBUT, 4.9s vs. 6.7s).30

The proposed pathomechanisms behind tear instability in VDT users are reduced blink rate and increased tear evaporation. The degree of change in blink rate with VDT use has been variable across the literature, with two studies noting significant reductions in the blink rate after 60 min of computer work in symptomatic VDT users.21,22 The reduction in blink rate was insignificant in asymptomatic users after 60 min of VDT use.21 Although it cannot be easily measured, another hypothesis is that tear evaporation increases with VDT use. This can be driven by reduced blinking, but also by other mechanisms such as changes in lipid layer thickness, lacrimal gland activity, and/or meibomian gland loss. In support of decreased blink rate as a contributor to both symptoms and signs of VDT DED, studies have found that intentional eye-opening leads to ocular symptoms and TBUT reductions. In a study of 25 asymptomatic VDT users, sustained eye opening (as long as possible) worsened ocular symptoms,23 reduced TBUT, and lowered mechanical corneal thresholds (increased sensitivity), measured using Belmonte esthesiometer. The worsening of ocular symptoms correlated with decreased tear stability and corneal thresholds, thereby implicating the role of corneal nerve function and blinking in VDT-associated DED.

Different treatment options have been explored for improving tear stability in VDT users (Table 2). The treatments targeted improving blink rate with neurostimulation and blink promoting applications, reducing tear evaporation with protective eyewear and a warm environment, or tear film substitution with ocular lubricants. Most studies were designed as prospective open label trials without randomization and blinding. Some compared the intervention with a control group, however the effects of interventions were studied for a short duration, ranging from intervention given for 15 min to maximum of 90 days. Moreover, the enrolled study subjects were mostly healthy VDT users (without dry eye symptoms) in majority of studies.

Several strategies have been explored for their effect on tear parameters and blink rate, including nerve stimulation and computer software. Periorbital transcutaneous electric nerve stimulation (TENS) thrice a week for two weeks increased tear film stability and tear secretion in asymptomatic VDT users after the third and sixth sessions.30 It also increased the blink rate by six per minute, though this increase was not statistically significant. In this study, the beneficial effect of TENS was measured immediately after the sessions, hence after-effects or long-term effects of TENS are unknown. Other approaches have also been investigated. One study examined the impact of software that prompts users to blink at regular intervals while using a VDT device. While blink rates marginally improved while using the blink-blink software, this did not translate into a significant improvement in TBUT values after 15 days of use. Another commonly employed strategy is the 20-20-20 rule, i.e., looking 20 feet away for the 20s every 20 minutes. While employing this strategy for 2 weeks did improve dry eye symptoms, no change was noted in TBUT values.31 Some potential limitations to blink apps and the 20-20-20 rule are patient compliance and the potential for brain conditioning after using these applications.

The impact of eyelid warming devices, goggles or moist air devices have been studied as methods to reduce tear evaporation and improve tear parameters. Warm, moist chamber goggles use for 15 minutes improved dry eye symptomatology and NIBUT significantly (measured at 60 min from use), comparable to a single drop instillation of 0.1% sodium hyaluronate (SH).25 However, it is unclear how important the warming aspect of masks are as another study showed similar increases in TBUT with warming or non-warming eye masks use for two weeks.26 Besides a significant improvement in TBUT, no differences in Schirmer values, Meibomian glands expressibility, or ocular surface staining scores were noted with eye mask use. However, it is not clear that eyelid warming is the optimal strategy to target tear stability as using a moist, cool air device in the office for 4 hours a day for five days also significantly improved dry eye symptomatology and TBUT values.27 Hence, warming masks/warm compress and moist cool air at the workplace have both been investigated as treatment options for VDT users with encouraging results. However, additional validation is required in larger cohorts. Topical therapies have also been studied in VDT associated DED. Use of ocular lubricants containing hydroxypropylmethyl cellulose or carboxymethyl cellulose for three months in an open-label trial improved TBUT values equally but a marginally higher OSDI improvement was noted with hydroxypropylmethyl cellulose.35

Based on summarized studies, tear stability is often reduced in symptomatic and asymptomatic VDT users, though VDT tasks impact stability more so in symptomatic VDT users. The effect seems to be independent of VDT type but stability is negatively related to duration of VDT use. Periorbital nerve stimulation, eyelid warming devices, cool moist air, and lubricants can improve tear stability in VDT users. Future studies are needed to further explore risk factors and treatments for tear instability in VDT users.

Lacrimal Gland

The relationship between VDT use and lacrimal gland activity is not clear, with mixed findings across studies. Most studies have used the Schirmer test to examine lacrimal gland activity and have reported mostly normal Schirmer values (non-anesthetized values greater than 10 mm) in VDT users (mean 16.2 mm).3,8,10,11,13,15,30–32,34,36,39 However, one study did find a significantly lower Schirmer value (decrease of 8.2 mm) in VDT users versus non-users.34 Similar to that noted for tear stability, differences in gland activity have been observed between symptomatic and asymptomatic VDT users, with symptomatic users having more abnormal Schirmer results (mean difference of 4.8, 9.1 mm).13,21 However, this finding has not been uniform, with no difference (0.8 mm) found in another study.32

Studies have found disparate results regarding that impact of VDT work on Schirmer values. Of five studies that looked at change with VDT use, one reported a significant reduction of 2.1 mm,18 and four reported no change after one to 4 hours of computer work.17,20,21,29 It is possible, however, that these studies did not observe VDT users for long enough as Schirmer values were significantly lower in long-term VDT users that reported using devices for greater than 8 hours a day compared to short-term (<3 hours/day) users (13.2 vs. 32.3 mm).21 However, other studies did not reproduce these findings, with no differences in Schirmer values noted in long-term VDT users who report > 4 versus <4 hours of device use a day (19 vs. 18.2 mm).30 Overall, some studies have found that long term VDT use, in general, has an impact on Schirmer values. One study reported that long-term VDT users (>12 years of use) had lower Schirmer values compared to those with <12 years of VDT use, although Schirmer scores in both groups were normal (mean 17.2 mm vs 20.3 mm).31 Interestingly, reduced Schirmer values did not correlate with dry eye symptomatology or other tear film parameters. TBUT, corneal staining, meibum scores were no different in eyes with less than 10 mm versus normal Schirmer values.30 Other studies have supported these findings as subjective symptomatology scores of 561 VDT users were not associated with Schirmer values (19 vs. 18.2 mm p = .0.39) in one study.32

Lacrimal gland activity has also been examined with respect to VDT use in animal models. In one study, rats were placed on a swing in front of a fan. This model was attempted to reproduce VDT use as rats needed to stay alert on the swing (with reduced blinking) and the fan was used to increase tear evaporation. Schirmer scores were found to decrease over time, with significant differences noted after 10 days as compared to baseline. Furthermore, ten days of resting were required for Schirmer values to return to baseline. Histologically, the lacrimal gland showed retention of large cytoplasmic secretory vesicles within acini and reduced cell number in the rat lacrimal glands.

With respect to treatment, several therapies have been studied in relationship to lacrimal gland activity in VDT users. Three periorbital transcutaneous electric nerve stimulation sessions improved TMH in asymptomatic VDT users. However, use of warming goggles, the 20-20-20 rule, lubricating eye drop (e.g., 0.15%, 1% sodium hyaluronate), and omega fatty acid supplements did not alter Schirmer values (Table 2; 36, 37, 27) in VDT users. Three months of therapy with 0.5% carboxymethylcellulose and 0.3% hydroxypropyl methylcellulose improved Schirmer values significantly in symptomatic VDT users.5 Again, results need to be interpreted with caution as majority of studies were open-label and evaluated the effects following short-term application.

In summary, the impact of VDT use on lacrimal gland activity is unclear, with some studies noting differences by years of VDT use, but with mostly normal Schirmer values in both groups.34 Also, the reason behind reduced lacrimal gland activity and the histologic changes in the glands of an animal VDT model is unclear. Future studies are needed to further explore these relationships.

Tear Meniscus Height (TMH)

VDT use has not been found to impact TMH. TMH represents the tear lake volume distributed along the eyelid margins that can be measured using OCT or other dry eye diagnostic devices. The reported mean TMH values vary from 0.19 to 0.33 mm in VDT users.8,16,20,21,38,40 Unlike tear stability and tear production, no differences in TMH have been noted in relationship to ocular symptoms.16 TMH values also do not seem to change with VDT use. Following VDT use for one to 4 hours, TMH values remained unchanged.20–22 However, the amount of visual information presented on a VDT does seem to impact TMH. In one study, playing games with a high speed of visual information led to decreased TMH values more so than playing games with low rates of visual information.24 It is postulated that increased evaporation and reduced lacrimal gland activity may reduce tear volume, but reduced tear outflow through the lacrimal drainage system (due to a lower blink rate) might be responsible for the normal TMH values noted across studies.

Regarding treatments, three periorbital TENS sessions improved TMH in asymptomatic VDT users, however, the study did not evaluate symptomatic VDT users.28 The use of warming goggles, the 20-20-20 rule, lubricating eye drops (e.g., 0.15%, 0.1% sodium hyaluronate), and omega fatty acid supplements did not alter TMH values significantly in VDT users.27,35,36 In summary, it appears that the tear film reservoir is essentially normal, as denoted by normal TMH values, in VDT users.

Tear Osmolarity

Elevated tear osmolarity in DED can occur secondary to reduced tear volume, increased evaporation, or tear instability. Two studies have looked at tear osmolarity values with respect to VDT use.18,21 Both studies found that mean osmolarity values in VDT users were below 308 mOsm/L (one commonly used cut-off for labelling DED). As with stability, symptomatic VDT users had higher tear osmolarity than asymptomatic users (305 mOsm/L versus 285 mOsm/L; p < .00001).21 Variable findings have been noted with respect to the impact of a VDT task on tear osmolarity. In one study, a VDT task (office work) led to a mean increase of 5 mOsm/L (p = .03) after a day at the office in 51 symptomatic VDT users which was greater than the increase of 1.9 mOsm/L noted in 26 non-VDT users who were engaged in non-VDT (janitorial) work at the hospital.18 In another study, a short-term task of one hour of VDT use non-significantly increased osmolarity by 2 mOsm/L (p > .05) in symptomatic VDT users, whereas no change was observed in asymptomatic VDT users.21 In summary, while tear instability and decreased blink have been noted in VDT users, these changes have not clearly been demonstrated to impact tear osmolarity. More data are needed to establish the impact of VDT use on tear osmolarity.

Meibography & Lipid Layer

Some Meibomian glands abnormalities (loss and altered meibum expressibility) have been noted in symptomatic VDT users. Three studies have examined Meibomian gland health in VDT users using meibography and meibum expressibility scores.21,26,30 Overall, median gland expressibility scores were higher (more abnormal) in symptomatic VDT users compared to asymptomatic VDT users (2 vs 0, scale 0–3).21 Short-term use of VDT, however, was not found to change meibum expressibility. In two studies, expressibility was unchanged after an hour of the VDT task.17,21 Regarding treatments, 2 weeks of eyelid-warming device improved meibum expressibility scores by 0.7 from an average of 1.5 at baseline.26 Meibum quality has been overall noted as normal in VDT users with one study reporting clear meibum that did not change in consistency with one hour of VDT task.21

Gland drop-out, assessed with meibography, has also been studied with respect to VDT use. One study reported that VDT use was not related upper or lower Meibomian gland (MG) dropout.26 Similar to tear stability, some studies found a greater degree of MG dropout in symptomatic versus asymptomatic VDT users.21 In symptomatic VDT users, gland dropout (74.3% vs. 11.4%) and partial glands (68.6% vs. 48.6%) were more frequent compared to asymptomatic VDT users.21 Long hours of VDT use was found to impact Meibomian gland loss. In one study, a higher number of individuals who were long-term VDT users (>4 hours/day) had a Meiboscore of ≥ 3 (i.e., >67% of gland area loss) compared to short-time VDT users i.e, <4 hours/day (40.4% versus 3.8%).30 No studies have evaluated the effects of different treatment modalities on gland dropout areas.

Lipid layer thickness (LLT) has also been examined in relationship to VDT use in two studies. The thickness of the lipid layer in the tear film is impacted by many factors, including the status of Meibomian glands. Two studies looked at LLT in VDT users- one in asymptomatic VDT users (n = 12)22 and another in symptomatic VDT users (n = 29).29 The Guillon scale range1–5 was used to measure LLT with a median grade of 3 in both studies.22,29 One hour of smartphone use did not alter the LLT values in asymptomatic VDT users.22 Similarly, two weeks of the 20-20-20 rule did not alter LLT values in symptomatic individuals (Table 2).29

VDT has been found to impact MG status in some ways. The strongest signals were with respect to MG expressibility and dropout, which were found reduced in symptomatic VDT users compared to asymptomatic ones. The available limited data shows no significant impact of VDT on meibum quality or LLT. Reduced blink rate may contribute to the noted abnormalities in meibum expressibility and quality scores.

Goblet Cells

VDT may impact goblet cell health. Goblet cell density can be quantified with impression cytology, and goblet cell health can be examined via surrogate measures such as tear MUC5AC levels, or mRNA expression of mucin. In one study, impression cytology taken from the inferior bulbar conjunctiva revealed goblet cell density reduction in 344 VDT users compared to 371 non-VDT users (1576 vs. 976 cells/mm2; p < .001).34 Reduced goblet cell density correlated with dry eye symptomatology (r = 0.57). Expression of different mucins in the tears/conjunctiva has also shown differences in VDT users. Mucin MUC5AC concentration in tears (measured using ELISA) was lower in symptomatic VDT users and VDT users who worked for more than 7 hours a day compared to asymptomatic users and those that worked less than 7 hours a day.39 Another study found reduced mRNA expression of MUC1, MUC16, and MUC20 in the conjunctival impression cytology specimens of VDT users with DED symptoms and signs (OSDI >13 AND TBUT < 10 s or > 5 corneal or > 9 conjunctival staining spots) compared to VDT users not meeting the DED criteria.16 However, not all mucins were differentially expressed in VDT users with and without DED. Specifically, mRNA expression of MUC5AC and MUC4 were similar in VDT users with and without DED.16 Individuals with reduced mucin concentration also had low TBUT values, suggesting a relationship between these two metrics.39 No studies have examined the effect of VDT task on goblet cell activity or the impact of treatments on goblet cell health. Future research is needed to examine mucin layer alterations in VDT users and the impact of mucin deficiency on tear film stability.

Corneal Staining

Disparate findings have been noted in relationship to VDT use and corneal staining. Corneal staining reflects the health of corneal epithelium and can be measured using different grading systems. The grading systems divide the cornea into 3 or 4 quadrants and quantify the density of spots as 0,1,2,3. The final score is given as a summation of all quadrants. Of 36 studies, 10 assessed the ocular surface staining in VDT users and most reported minimal or no corneal staining in VDT users.15,22,28,31 The mean corneal stain grading in VDT users varied from 0 to 3.7.3,28,31,32,35 No significant differences in corneal staining score have been noted VDT time (long versus short-term use) or symptoms (symptomatic versus asymptomatic)13,32 One study, however, did find that symptomatic VDT users had more abnormal tear metrics, including staining, than asymptomatic users. Specifically, in 26 symptomatic and 53 asymptomatic users (mean 8 hours of VDT use in both groups), TBUT values were lower (mean 3 vs. 12 seconds), corneal staining was higher (mean 1 vs. 0; p = .002), and conjunctival MUC16 and MUC1 levels were lower in symptomatic individuals.16 However, no correlation was found between MUC1, MUC16 levels and dry eye symptoms or tear film parameters.

Other studies, however, did not replicate these findings, with similar levels of corneal staining (mean 1.2) in 86 symptomatic and 22 asymptomatic VDT users, despite lower Schirmer values in symptomatic users.13 With respect to VDT time, mean staining was not significantly different in those using devices for a mean of 8.3 h/day versus 3.2 h/day (3.7 vs 1.5, p = .5).30 Interestingly, VDT task also did not worsen corneal staining scores, as no changes were noted after reading an e-book for 20 minutes or playing videogames for three days.11,33 Interventions, such as a cool, moist environment, the 20-20-20 rule, and the use of lubricant drop (0.15% SH) also did not impact corneal staining grades (Table 2).27,29,35 In summary, VDT DED does not seem to be driven by corneal staining, as most studies have found minimal or no corneal staining in symptomatic and asymptomatic VDT users.

Ocular Congestion

Many VDT users subjectively complain of conjunctival congestion (81.3% in one study).39 Bulbar redness (BR) can also be objectively measured, for example with the Oculus keratograph 5 M for nasal and temporal quadrants. Three studies have examined mean BR values (nasal and temporal) in VDT users with reported mean values of 0.7 to 1.1,17,21 No differences have been noted in BR values between symptomatic vs. asymptomatic VDT users (0.8 vs.1; p = .35).21 VDT use has been found to worsen conjunctival congestion. One study found that BR values increased in symptomatic VDT users after one hour of computer use compared to asymptomatic users (mean change of 0.16 (p = .01) vs. 0.06 (p = .15).21 Another study reported worsening BR levels with two hours of smartphone use in asymptomatic smartphone users with the proportion of individuals with > 1 redness score on Keratograph increasing from 15.8% to 38.3% with use.17 With respect to treatment, BR scores did not change with ocular lubricant use during a 15-minute reading task.1 The molecular basis for the noted increase in bulbar conjunctional congestion with VDT use is worth further exploring.

Discussion

Advancements in technology and the advent of concepts like the metaverse and artificial intelligence have significantly contributed to the increased screen time associated with VDTs in recent years.41 In order to ascertain the limits of safe VDT usage, we need to understand the extent of tear film changes in context to duration of VDT use, type of VDT use, its impact on ocular surface and the parameters that predict the development of tear film changes. Then, management options can be devised appropriately for the prevention or treatment of DED in appropriate individuals. As such, this review systemically examined the impact of VDT use on tear film parameters. Prior studies have highlighted that VDT use reduces blink rate and thus, we did not focus on this aspect of ocular health. We found that with respect to DE signs, the strongest noted signal was reduced tear stability. Weaker signals were noted with respect to lacrimal gland and goblet cell health, presenting as reduced Schirmer and mucin levels.

Reduced tear stability may be a consequence of decreased blink rate, increased tear evaporation (which has not been directly measured in prior studies), reduced tear production, altered lipid composition, and reduced mucin levels. It is unclear if one of these changes predominates or whether complex interactions between all of them are responsible for reduced tear stability seen in VDT users.

First, tear stability can be affected by blinking. Though TMH is normal in VDT users (indicating an adequate tear film reservoir), blink is necessary to spread the tears over the corneal surface. The blink reflex is also necessary for initiating the reflex secretion from the lacrimal gland. Ideally, the blink interval should be shorter than the TBUT. In one study, VDT users were divided into two categories, those whose blink interval was longer than their TBUT and those whose blink interval was shorter than their TBUT. VDT users with a longer blink interval had significantly lower Schirmer values, TBUT, and blink rates than their counterparts (Table 1).3 As noted above, tear instability is unlikely to be driven by an abnormal tear reservoir as TMH has been reported normal across studies.8,16,20,21,38 Similarly, tear instability is also likely not driven by lacrimal gland hypofunction as Schirmer scores have been normal (>10 mm) in the majority studies. Nevertheless, there is some remaining controversy in this regards as Schirmer values were related with duration of VDT use; that is, baseline Schirmer values were less in long-term VDT users compared to short-term VDT users,21 and animal models highlighted a decrease in tear production with decreased blink and evaporative stress.

While some MG changes were noted in VDT users (changes in expressibility, dropout, and shortening), other measures such as meibum quality and LLT were not impacted by VDT use.21,22,26,29,30 Though long-term VDT use was associated with gland dropout and shortening in the studies, more longitudinal studies are needed to establish an association between VDT use and MG’s structural alterations.21,26,30 Reduced goblet cell activity and tear mucin levels have been noted in VDT users with short TBUT, but only a limited number of studies have looked at these parameters.

Regardless of cause, tear stability has been found to vary with the VDT task. The majority of studies agree that TBUT values, whether invasively or non-invasively measured, decrease with VDT task.18,20–22,38 This may be partially driven by the known impact of VDT on blink rate reduction. Other tear parameters, however, have not be found to change with VDT use in majority of studies.17,20–22 Specifically, short-term VDT use (i.e., 15 min or one hour) did not affect MG expressibility and quality, TMH or Schirmer values. Data are insufficient to conclude the effects of VDT use on tear film parameters such as tear osmolarity, goblet cells, and tear mucin levels as small number of studies have looked at them. A further limitation is that short-term use of VDT devices likely does not adequately capture the effects of a full day of office work. Hence, study of diurnal variations in dry eye symptomatology and tear film parameters after long hours of VDT use are needed to ascertain the real-world effects of VDTs. Symptom status has also been found to impact tear film parameters in VDT users, with symptomatic VDT users having, on average, worse DE signs (most notably, TBUT) than asymptomatic users. However, most of these studies did not include non-VDT controls (with and without DED symptoms) and as such, the contribution of VDT on symptoms and signs cannot be fully elucidated. Furthermore, it is not clear why some individuals become symptomatic and others stay asymptomatic despite similar VDT use.

Different interventions that target eyelid blinking, tear evaporation or supplementing tear volume have been explored in VDT users. Interventions include use of electrical stimulation, blink improving apps, eyelid warming devices, moist goggles, lubricants, and omega fatty acids supplementation. Electric stimulation of the periorbital area (aimed to improve blink reflex), improved the TMH and TBUT, but interestingly, did not have a significant effect on blink rates.30 Blink-blink app and the use of the 20-20-20 rule for short duration of two weeks did not impact tear film parameters either, but improved symptoms from baseline.7,31 Brain conditioning to these approaches may be one reason for the lack of change in tear parameters as individuals may learn to ignore the app over time. Eyelid warming has conflicting effects on VDT users as two weeks use of both warming and non-warming masks showed subjective improvement and a significant change in NIBUT. However, warm moist goggles did better at improving NIBUT better than ocular lubricants in another study.25 Even without warming, moist room environment alone showed subjective improvement and increased TBUT values.27 However, the effects were studied after 5 hours of use. Omega fatty acids supplementation has been explored in one study alone, and subjects did feel better but no change in tear film parameters was noted. The use of lubricants have also shown conflicting effects in two studies, where CMC and HPMC improved tear film parameters (TBUT, Schirmer) significantly, but 0.15% SH eye drops did not improve TBUT or Schirmer compared to VDT users who did not use any eye drops.35 The heterogeneity across studies in terms of inclusion of asymptomatic VDT users, lack of comparison groups of non-users, short term intervention for less than an hour, and open-label design are major limitations of intervention studies.

Future Research Possibilities

The tear film behaves differently in long-term versus short-term VDT users.3,21,31,39 There are few exceptions to this rule where differences were found despite similar working hours.16 Studies are needed to clarify these differences. Also, the impact of lifestyle on DED symptomatology of VDT users is worth exploring. The role of psychogenic factors like anxiety, sleep disturbances or work related stress may also contribute to discrepancies between symptomatic and asymptomatic VDT users and need further study as does the impact of VDT use on corneal nerve function. Treatment options need to be explored in VDT users, with more of a focus on their impact in symptomatic users, and with more robust study designs (e.g., long-term treatments, randomized, masked). Lifestyle modifications can also impact VDT-associated DED management and randomized controlled trials are needed to assess these interventions. These directions are worthwhile because upcoming lifestyle epidemic of VDT associated DED will impact the quality of life and work of VDT users who mainly comprise of young to adult population who are active contributors to the economy. Hence, understanding the pathomechanisms and preventive/treatment strategies for VDT associated DED is crucial for addressing this health issue.

Funding

The author (S.S) is an early career India Alliance-Wellcome Trust fellow and funded by the agency for the research (IA/CPHE/21/1/505970).

Footnotes

Disclosure statement

No potential conflict of interest was reported by the author(s).

References

  • 1.Talens-Estarelles C, Sanchis-Jurado V, Esteve-Taboada JJ, Pons ÁM, García-Lázaro S. How do different digital displays affect the ocular surface? Optometry And Vision Sci. 2020;97(12):1070–9. doi: 10.1097/OPX.0000000000001616. [DOI] [PubMed] [Google Scholar]
  • 2.Fjaervoll H, Fjaervoll K, Magno M, et al. The association between visual display terminal use and dry eye: a review. Acta Ophthalmol. 2022;100(4):357–375. doi: 10.1111/aos.15049. [DOI] [PubMed] [Google Scholar]
  • 3.Uchino M, Kawashima M, Uchino Y, Tsubota K, Yokoi N. Association between tear film break up time and blink interval in visual display terminal users. Int J Ophthalmol. 2018;11:1691. doi: 10.18240/ijo.2018.10.18. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Hirota M, Uozato H, Kawamorita T, Shibata Y, Yamamoto S. Effect of incomplete blinking on tear film stability. Optometry And Vision Sci. 2013;90(7):650–7. doi: 10.1097/OPX.0b013e31829962ec. [DOI] [PubMed] [Google Scholar]
  • 5.Ang CK, Mohidin N, Chung KM. Effects of wink glass on blink rate, nibut and ocular surface symptoms during visual display unit use. Curr Eye Res. 2014;39(9):879–84. doi: 10.3109/02713683.2013.859273. [DOI] [PubMed] [Google Scholar]
  • 6.Kawashima M, Tsuno S, Matsumoto M, Tsubota K. Hydrogen-producing milk to prevent reduction in tear stability in persons using visual display terminals. Ocul Surf. 2019;17(4):714–21. doi: 10.1016/j.jtos.2019.07.008. [DOI] [PubMed] [Google Scholar]
  • 7.Ashwini DL, Ramesh SV, Nosch D, Wilmot N. Efficacy of blink software in improving the blink rate and dry eye symptoms in visual display terminal users–A single-blinded randomized control trial. Indian J Ophthalmol. 2021;69(10):2643. doi: 10.4103/ijo.IJO_3405_20. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Patel S, Port MJ. Tear characteristics of the VDU operator. Optom Vis Sci. 1991;68(10):798–800. doi: 10.1097/00006324-199110000-00008. [DOI] [PubMed] [Google Scholar]
  • 9.Moon JH, Lee MY, Moon NJ. Association between video display terminal use and dry eye disease in school children. J Pediatric Ophthalmol Strabismus. 2014;51(2):87–92. doi: 10.3928/01913913-20140128-01. [DOI] [PubMed] [Google Scholar]
  • 10.Cortes M, Esposito G, Sacco R, Gillet VB, Ianni A, Micera A. NGF and iNOS changes in tears from video display terminal workers. Curr Eye Res. 2018;43(9):1119–25. doi: 10.1080/02713683.2018.1475014. [DOI] [PubMed] [Google Scholar]
  • 11.Prabhasawat P, Pinitpuwadol W, Angsriprasert D, Chonpimai P, Saiman M. Tear film change and ocular symptoms after reading printed book and electronic book: a crossover study. Jpn J Ophthalmol. 2019;63(2):137–144. doi: 10.1007/s10384-018-00648-1. [DOI] [PubMed] [Google Scholar]
  • 12.Tichenor AA, Ziemanski JF, Ngo W, Nichols JJ, Nichols KK. Tear film and meibomian gland characteristics in adolescents. Cornea. 2019;38(12):1475–82. doi: 10.1097/ICO.0000000000002154. [DOI] [PubMed] [Google Scholar]
  • 13.Sánchez-Valerio MD, Mohamed-Noriega K, Zamora-Ginez I, Baez Duarte BG, Vallejo-Ruiz V. Dry eye disease association with computer exposure time among subjects with computer vision syndrome. Clin Ophthalmol. 2020;14:4311–4317. doi: 10.2147/OPTH.S252889. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Yokoi N, Uchino M, Uchino Y, et al. Importance of tear film instability in dry eye disease in office workers using visual display terminals: the osaka study. Am J Ophthalmol. 2015;159(4):748–54. doi: 10.1016/j.ajo.2014.12.019. [DOI] [PubMed] [Google Scholar]
  • 15.Cantó-Sancho N, Porru S, Casati S, Ronda E, Seguí-Crespo M, Carta A. Prevalence and risk factors of computer vision syndrome—assessed in office workers by a validated questionnaire. PeerJ. 2023;11:e14937. doi: 10.7717/peerj.14937. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Duan H, Yang T, Zhou Y, et al. Comparison of mucin levels at the ocular surface of visual display terminal users with and without dry eye disease. BMC Ophthalmol. 2023;23(1):1–8. doi: 10.1186/s12886-023-02931-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Wang C, Yuan K, Mou Y, et al. High-intensity use of smartphone can significantly increase the diagnostic rate and severity of dry eye. Front Med (Lausanne) 2022;9:829271. doi: 10.3389/fmed.2022.829271. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 18.Yazici A, Sari ES, Sahin G, et al. Change in tear film characteristics in visual display terminal users. Eur J Ophthalmol. 2015;25(2):85–9. doi: 10.5301/ejo.5000525. [DOI] [PubMed] [Google Scholar]
  • 19.Kim DJ, Lim CY, Gu N, Park CY. Visual fatigue induced by viewing a tablet computer with a high-resolution display. Korean J Ophthalmol. 2017;31(5):388–93. doi: 10.3341/kjo.2016.0095. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Choi JH, Li Y, Kim SH, et al. The influences of smartphone use on the status of the tear film and ocular surface. Plos One. 2018;13(10):e0206541. doi: 10.1371/journal.pone.0206541. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Srivastav S, Basu S, Singh S. Tear film changes in symptomatic versus asymptomatic video display terminal users following computer challenge test. Ocul Surf. 2023;30:53–6. doi: 10.1016/j.jtos.2023.08.003. [DOI] [PubMed] [Google Scholar]
  • 22.Golebiowski B, Long J, Harrison K, Lee A, Chidi-Egboka N, Asper L. Smartphone use and effects on tear film, blinking and binocular vision. Curr Eye Res. 2020;45(4):428–34. doi: 10.1080/02713683.2019.1663542. [DOI] [PubMed] [Google Scholar]
  • 23.Awisi-Gyau D, Begley CG, Situ P, Simpson TL. Changes in corneal detection thresholds after repeated tear film instability. Invest Ophthalmol Vis Sci. 2019;60(13):4234–40. doi: 10.1167/iovs.19-27802. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Cardona G, García C, Serés C, Vilaseca M, Gispets J. Blink rate, blink amplitude, and tear film integrity during dynamic visual display terminal tasks. Curr Eye Res. 2011;36(3):190–7. doi: 10.3109/02713683.2010.544442. [DOI] [PubMed] [Google Scholar]
  • 25.Ren Y, Chen J, Zheng Q, Chen W. Short-term effect of a developed warming moist chamber goggle for video display terminal-associated dry eye. BMC Ophthalmol. 2018;18(1):1–8. doi: 10.1186/s12886-018-0700-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Sun CC, Lee CY, Hwang YS, Michihito I, Tagami K, Hsiao CH. Effect of warming eyelids on tear film stability and quality of life in visual display terminal users: a randomized controlled trial. Sci Rep. 2020;10(1):16919. doi: 10.1038/s41598-020-73779-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Hirayama M, Murat D, Liu Y, Kojima T, Kawakita T, Tsubota K. Efficacy of a novel moist cool air device in office workers with dry eye disease. Acta Ophthalmol. 2013;91(8):756–62. doi: 10.1111/j.1755-3768.2012.02485.x. [DOI] [PubMed] [Google Scholar]
  • 28.Zeng W, Lou H, Huang Q, Li K, Liu X, Wu K. Eliciting blinks by transcutaneous electric nerve stimulation improves tear fluid in healthy video display terminal users: a self-controlled study. Medicine. 2022;101(44):e31352. doi: 10.1097/MD.0000000000031352. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Talens-Estarelles C, Cerviño A, García-Lázaro S, Fogelton A, Sheppard A, Wolffsohn JS. The effects of breaks on digital eye strain, dry eye and binocular vision: testing the 20-20-20 rule. Contact Lens Anterior Eye. 2023;46(2):101744. doi: 10.1016/j.clae.2022.101744. [DOI] [PubMed] [Google Scholar]
  • 30.Wu H, Wang Y, Dong N, et al. Meibomian gland dysfunction determines the severity of the dry eye conditions in visual display terminal workers. Plos One. 2014;9(8):e105575. doi: 10.1371/journal.pone.0105575. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Nakamura S, Kinoshita S, Yokoi N, et al. Lacrimal hypofunction as a new mechanism of dry eye in visual display terminal users. Plos One. 2010;5(6):e11119. doi: 10.1371/journal.pone.0011119. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.Yamanishi R, Uchino M, Uchino Y, Kawashima M, Dogru M, Yokoi N, Tsubota K. Changes in distribution of dry eye diagnostic status among visual display terminal workers according to the revised criteria of the asia dry eye society. Cornea. 2020;39(5):578–83. doi: 10.1097/ICO.0000000000002218. [DOI] [PubMed] [Google Scholar]
  • 33.Trancoso Vaz F, Fernández-López E, Roig-Revert MJ, Martín A, Peris-Martínez C. Improving Visual Comfort during Computer Gaming with Preservative-Free Hyaluronic Acid Artificial Tears Added to Ergophthalmological Measures. Vision. 2023;7(1):5. doi: 10.3390/vision7010005. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Bhargava R, Kumar P, Arora Y. Short-term omega 3 fatty acids treatment for dry eye in young and middle-aged visual display terminal users. Eye & Contact Lens: Science & Clinical Practice. 2016;42(4):231–6. doi: 10.1097/ICL.0000000000000179. [DOI] [PubMed] [Google Scholar]
  • 35.Rajendraprasad RM, Kwatra G, Batra N. Carboxymethyl cellulose versus hydroxypropyl methylcellulose tear substitutes for dry eye due to computer vision syndrome: comparison of efficacy and safety. Int J Appl Basic Med Res. 2021;11(1):4. doi: 10.4103/ijabmr.IJABMR_399_20. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Kojima T, Ibrahim OM, Wakamatsu T, et al. The impact of contact lens wear and visual display terminal work on ocular surface and tear functions in office workers. Am J Ophthalmol. 2011;152(6):933–940. doi: 10.1016/j.ajo.2011.05.025. [DOI] [PubMed] [Google Scholar]
  • 37.Jaiswal S, Asper L, Long J, Lee A, Harrison K, Golebiowski B. Ocular and visual discomfort associated with smartphones, tablets and computers: what we do and do not know. Clin Exp Optometry. 2019;102(5):463–77. doi: 10.1111/cxo.12851. [DOI] [PubMed] [Google Scholar]
  • 38.Talens-Estarelles C, García-Marqués JV, Cerviño A, García-Lázaro S. Digital display use and contact lens wear: effects on dry eye signs and symptoms. Ophthalmic Physiol Opt. 2022;42(4):797–806. doi: 10.1111/opo.12987. [DOI] [PubMed] [Google Scholar]
  • 39.Uchino Y, Uchino M, Yokoi N, et al. Alteration of tear mucin 5AC in office workers using visual display terminals: the osaka study. JAMA Ophthalmol. 2014;132(8):985–92. doi: 10.1001/jamaophthalmol.2014.1008. [DOI] [PubMed] [Google Scholar]
  • 40.Moon JH, Kim KW, Moon NJ. Smartphone use is a risk factor for pediatric dry eye disease according to region and age: a case control study. BMC Ophthalmol. 2016;16(1):188. doi: 10.1186/s12886-016-0364-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 41.Craig JP, Alves M, Wolffsohn JS, Downie LE, Efron N, Galor A, Gomes JAP, Jones L, Markoulli M, Stapleton F, Starr CE, et al. TFOS Lifestyle Report Executive Summary: A Lifestyle Epidemic - Ocular Surface Disease. Ocul Surf. 2023;30:240–253. doi: 10.1016/j.jtos.2023.08.009. [DOI] [PubMed] [Google Scholar]

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