Ⅰ. Introduction
Dry eye disease (DED) was defined in the 2017 TFOS DEWS II(Tear Film and Ocular Surface Society, Dry Eye Workshop II) as a multifactorial disease characterized by the loss of tear film homeostasis, tear instability, increased tear osmolarity, ocular surface inflammation, and neurosensory abnormalities.1,2)
Approximately 125 million people worldwide wear contact lenses.3) Contact lenses are widely used to correct refractive errors while minimizing changes in appearance. However, contact lens wear can cause complications such as infections, allergic conjunctivitis, corneal diseases, and, notably, dry eye syndrome.3) Dry eye is a common symptom experienced by 30%-50% of contact lens wearers, and severe cases can lead to discomfort and intolerance, making it a significant clinical issue.4,5)
The diagnosis of dry eye involves both subjective symptoms, such as foreign body sensation and visual disturbances, and objective assessments, including tear breakup time(TBUT), corneal staining, and tear secretion tests.2,6) Recently, a more rapid and non-invasive assessment tool called Occutube(OccuTech Co., Seongnam, Korea) has been developed. This method measures tear volume in a shorter time (~5 seconds) compared to the conventional Schirmer test,7,8) offering a more objective and efficient evaluation tool.
This study aimed to analyze the effects of alcohol consumption and electronic device use on dry eye symptoms based on contact lens wear. We examined tear volume using Occutube, non-invasive tear breakup time(NIBUT), and blink rate to explore the correlation between contact lens wear and dry eye disease.
Ⅱ. Methods
1. Participants
This study was approved by the Institutional Review Board of Eulji University(IRB No.: EU24 -05).
The study included male and female university students in their 20s. Participants with ocular or systemic diseases affecting vision and those who had undergone corneal refractive surgery were excluded. A total of 32 students(64 eyes) participated( Mean±SD age: 20.25±2.010 years). Before participation, all subjects received detailed verbal and written explanations of the study's purpose and examination procedures and provided informed consent.
The contact lens-wearing group consisted of individuals who wore lenses for at least 8 hours per day, at least 3 days per week. The nonwearing group consisted of individuals who had not worn contact lenses for at least one week before the study.
The contact lens-wearing group consisted of individuals who wore contact lenses for an average of at least 8 hours per day and at least 3 days per week, while the non-wearing group included individuals who had not worn contact lenses for one week prior to the examination. Each group consisted of 16 participants.
2. Examination Methods
1) Dry Eye Diagnosis
Dry eye was assessed using three methods: blink rate, NIBUT, and Occutube test. Dry eye was diagnosed if at least two of the following criteria were met: a blink rate of 15 or more per minute, NIBUT of 12 seconds or less, or an Occutube measurement of 5 mm or less.8-10)
Both contact lens wearers and non-wearers underwent the same three-phase testing procedure. After the first test, participants watched a 20-minute documentary on a 6.1-inch smartphone screen. The second test was conducted immediately afterward. To avoid overlapping stimuli, a 30-minute break without electronic device use followed. Participants then consumed alcohol, and after confirming a blood alcohol concentration of 0.03%, the third test was performed.
2) Tear Volume Evaluation
Tear volume was measured using Occutube, a modified Strip Meniscometry(SMTube). Occutube is an 85 mm-long, 7.2 mm-wide, 0.5 mm-thick plastic tube with a 0.8 mm absorbent tip that does not touch the ocular surface but absorbs tears from the lower tear meniscus. Measurements were taken after placing Occutube tip in the lower tear meniscus for 5 seconds, with values below 5 mm indicating dry eye(Fig. 1).9,10)
3) Non-Invasive Tear Breakup Time (NIBUT)
NIBUT was measured using the Keratograph 5M(K5M, Oculus, Germany), Wavefront Analyzer (KR-1W, Topcon, Japan), and Autorefractive Keratometry(ARK, KR-8800, Topcon, Japan).
4) Blink Rate Assessment
A normal blink rate was set at 15 blinks per minute.9) If the proportion of incomplete blinks exceeded 30%, it was considered abnormal.
3. Statistical Analysis
Statistical analysis was performed using SPSS version 21.0(SPSS Inc., Chicago, IL, USA). All analyses were conducted with a 95% confidence interval, and a p-value of <0.05 was considered statistically significant.
Ⅲ. Results
In the contact lens-wearing group, blink rate was consistently higher than in the non-wearing group after baseline testing, electronic device use, and alcohol consumption, but these differences were not statistically significant(p=.288, p=0.321, p=0.613, Table 1).
In the non-wearing group, NIBUT values decreased in all conditions, with statistically significant reductions after baseline and electronic device use(p=0.010, p=0.001). The results after alcohol consumption were at the borderline of significance(p=0.057).
In the non-wearing group, Occutube test values were higher in all conditions but were significantly different only after alcohol consumption(p=0.016, Table 1). After electronic device use, significant changes were observed in blink rate and Occutube test values(p=0.001, p=0.000), whereas NIBUT remained unchanged(p=0.331). In contrast, after alcohol consumption, all parameters showed significant differences(p=0.039, p=0.000, p=0.000, Table 2).
In the wearing group, only blink rate changed significantly after electronic device use (p=0.034, Table 3), while only the Occutube test showed a significant difference after alcohol consumption (p=0.008). Dry eye prevalence increased after electronic device use in the non-wearing group and after alcohol consumption in the wearing group, with significant differences (p=0.028, p=0.022, Table 4).
Ⅳ. Discussion
The prevalence of dry eye disease is increasing among young adults due to the increased use of smartphones and computers, prolonged nearwork activities, a rise in contact lens wearers, and exposure to environmental pollutants.10,12) Regardless of the lens material, contact lens wear reduces both tear quantity and stability. In terms of tear film changes, rigid gas permeable (RGP) lenses promote reflex tear secretion but simultaneously decrease the tear volume in the lower conjunctival sac and reduce tear film stability. In contrast, soft contact lenses do not initially cause significant tear film changes, but prolonged use has been reported to result in reduced reflex tear secretion and lower tear volume in the lower conjunctival sac.13)
This study measured and analyzed the effects of alcohol consumption and electronic device use on dry eye symptoms using Occutube test, NIBUT, and blink rate. There are two main methods to measure tear breakup time(TBUT). One uses corneal topography to divide the cornea into multiple regions and determine an average TBUT, while the other employs fluorescein staining to observe the first tear film breakup. The latter tends to underestimate TBUT values compared to non-invasive methods.14)
A previous study by Kim et al.15) measured NIBUT after one hour of smartphone use under low-light conditions and found no statistically significant difference between pre- and post-use NIBUT values. In our study, NIBUT values were significantly different between contact lens wearers and non-wearers across all conditions. However, in the non-wearing group, the change in NIBUT after electronic device use was not statistically significant.
A study by Moon et al.16) investigated the effects of watching smartphone videos on dry eye symptoms in university students using blink rate and the Schirmer test. Their study found a statistically significant decrease in blink rate after watching videos. In contrast, our study found that blink rate was consistently higher in the contact lens-wearing group than in the non-wearing group across all conditions, although these differences were not statistically significant. This discrepancy may be due to the shorter video viewing time in our study(20 minutes) and the influence of contact lenses on blink behavior. However, both studies commonly indicated changes in tear secretion following electronic device use, as reflected by Schirmer and NIBUT measurements. In particular, in our study, the contact lens-wearing group exhibited greater dryness than the non-wearing group when comparing NIBUT values.
An earlier academic symposium study17) found that Occutube test results showed a significant decrease in tear volume in both groups after smartphone video viewing, with a particularly greater reduction in the contact lens-wearing group. However, in our study, only the nonwearing group exhibited a significant decrease in tear volume. This difference may be explained by several physiological mechanisms. First, soft contact lenses have inherent water content, which can help retain localized moisture. In addition, the physical presence of the lens may act as a barrier, reducing tear evaporation and preserving tear volume. Continuous mild stimulation from the lens may also promote reflex tearing. In contrast, the ocular surface of non-wearers is more directly exposed to environmental stressors, such as screen use and systemic dehydration from alcohol intake, which may cause a more pronounced reduction in tear production and stability.
In our study, subjective dryness severity also differed depending on contact lens wear status. This difference may be attributed to multiple physiological mechanisms. Contact lens wearers often experience chronic tear film instability and evaporative loss, which may heighten their sensitivity to external stressors. Neurosensory alterations in the cornea caused by long-term lens wear may also modulate symptom perception, making dryness feel more severe even with similar objective measurements. On the other hand, non-wearers may react more acutely to transient stressors due to the lack of ocular surface adaptation, leading to symptom exacerbation under specific conditions.
These findings are similar to previous research on patients with primary Sjögren’s syndrome, which reported that environmental factors such as temperature, humidity, and fine dust levels significantly influenced ocular discomfort and tear osmolarity.2) Like patients with Sjögren’s syndrome, contact lens wearers and non-wearers may exhibit differing susceptibility to environmental and behavioral factors, and further studies are warranted to explore these effects in depth.
A previous study also examined the effect of loose mask-wearing on TBUT using a cross-sectional and experimental design.14) That study included 60 eyes tested under three conditions—no mask, loosely fitted mask, and tightly fitted mask—each maintained for 10 minutes. A significant decrease in NIBUT was observed only in the loosely fitted mask condition(p=0.013), suggesting that maskinduced airflow may reduce tear film stability and exacerbate dry eye symptoms. Based on our findings, alcohol consumption and electronic device use should also be considered environmental or behavioral factors that can trigger or aggravate dry eye symptoms regardless of contact lens wear. Moreover, when combined with factors such as mask-wearing, the risk and severity of dry eye symptoms may be further elevated.
One limitation of this study is the relatively small sample size. Additionally, the duration of electronic device use was shorter than in some previous studies. Future research should aim to expand the sample size and investigate changes in dry eye symptoms based on various device types, usage durations, and environmental factors.
Ⅴ. Conclusion
This study analyzed the effects of alcohol consumption and electronic device use on dry eye symptoms in university students, depending on contact lens wear. Results showed that nonwearers experienced more significant irritation after electronic device use and alcohol consumption than wearers. Additionally, NIBUT values indicated that wearers generally experienced greater dryness regardless of stimulus type. Non-wearers showed increased dry eye symptoms after electronic device use, while wearers exhibited increased symptoms after alcohol consumption. In conclusion, alcohol consumption and electronic device use negatively affect dry eye symptoms, irrespective of contact lens wear. Future research should increase the sample size and investigate the impact of different types and durations of electronic device use on dry eye symptoms.
