Table 3.

Single visit studies with objective measures.

Study	Sample	Design	Preventive measure	TBUT	OSS	Blink rate	LLT	Symptom score	Outcome
Yee et al. 2007 (US)	40 computer users (50% DED)	Prospective, crossover design	MEGS + AT during computer use	↑	↑*			↑1	MEGS + AT improved DED patients' comfort and prevented TBUT decrease with VDT use. No significant improvement was noted in the asymptomatic control group
Ang et al. 2014 (MY)	26 visually healthy subjects	Prospective, controlled, crossover	Wink glasses during VDT use	—		↑		↑1	Use of wink glasses reduced ocular surface symptoms significantly compared to controls using plastic sheaths
Guillon et al. 2004 (UK)	20 CL users	Controlled pilot study	2% povidone preservative‐free lubricating AT		—			↑	AT improved visual acuity significantly. Dry eye symptoms decreased in all three installation modalities of eyedrops compared to no eyedrops
Bilkhu et al. 2020 (GB)	40 healthy to mild dry eyes	Controlled experimental study	Heat chamber goggles and liposomal spray after VDT use	—		—	↑	↑2	LLT and TMH were unchanged during VDT use but improved with treatment. TBUT and blink rate and symptoms worsened during VDT use, but only symptoms improved with treatment
Miura et al. 2013 (BR)	15 with symptoms, 15 healthy subjects	Prospective, controlled trial	Light‐emitting power device during VDT use	—	—	↑			In symptomatic subjects, light‐emitting power device increased blink rates during VDT use both with and without air‐conditioning. In controls, improvement was only seen with exposure to both VDT and air‐conditioning. TBUT and OSS did not improve in either group
Wang et al. 2017 (NZ)	44 computer workers	Prospective, controlled, crossover	USB‐desktop humidifier during VDT use	↑			—	↑3	Those using the humidifier had improved TBUT and subjective ocular comfort than the control group. The control group had a significant decrease in TBUT after VDT use. No change in TMH or lipid‐layer grade
Rempel et al. 2007 (US)	24 healthy, young adults	Prospective, controlled, crossover	Screen viewing distance between 52 and 73 cm					↑	A viewing distance of between 52 and 73 cm was associated with significantly less dry eye symptoms and improved convergence recovery when compared to distances up to 84 cm and down to 44 cm
Cardona et al. 2014 (ES)	11 visually healthy subjects	Controlled experimental	Three different blink animation programmes during VDT use			↑			One of the three blink animations improved blink rate significantly from baseline with no animation. It was also the second most intrusive animation according to the subjects
Ren et al. 2018 (CN)	22 VDT workers with DED	Prospective crossover design	WMCG for 15 min	↑			↑	↑4	Use of WMCG increased TBUT, TMH and LLT compared to the control group receiving SH 0.1% eyedrops. The intervention group's improved visual comfort persisted after 60 min compared to 30 min in the control group
Miyake‐Kashima et al. 2005 (JP)	7 visually healthy subjects	Prospective crossover design	VDT filter during screen use			—			Screen use without VDT filter resulted in a significantly worse asthenopic score, when compared to viewing with a VDT filter. Mean blink rate decreased significantly from baseline when not using a VDT filter. There was no such difference in blink rate when using with a VDT filter

¹ocular surface disease index (OSDI), ²symptom assessment in dry eye (SANDE), ³McMonnies dry eye questionnaire, ⁴visual analogue scale (VAS).

AT = artificial tears, CL = contact lens wear, DED = dry eye disease, LLT = lipid‐layer thickness, MEGS = microenvironment glasses, OSS = ocular surface staining, SH = sodium hyaluronate, TBUT = tear film break‐up time, TMH = tear meniscus height, VDT = video display terminal, WMCG = warming moist chamber goggles.

↑ Significant improvement at p < 0.05, — no significant difference.

^*Lissamine green staining showed significant results, not fluorescein staining.