By Anisha Narsam, Neurobiology, Physiology and Behavior ‘23
Author’s Note: I hope to raise awareness about treatments for eye strain from screen exposure because of the current pandemic and the increase in online interactions. This article is meant for students and individuals who work on devices with screens, such as computers or tablets, and want to treat their eye strain. I chose this topic because I have noticed an increase in my eye strain since the pandemic began and I wanted to research how to alleviate this condition for myself and for my peers. Through this article, I hope readers can understand the effectiveness of a range of treatments for eye strain from screen exposure with my analysis of seven peer-reviewed journal articles.
Excessive screen time, due to remote learning, is dramatically increasing the incidence of eye strain. Since this condition can elevate tiredness and reduce an individual’s ability to concentrate, promising treatments must be considered to avoid further ocular harm. Previous research on eye strain shows that when people spend a lot of time on their computer, they can benefit from taking frequent breaks away from their screens. However, with increased reliance on technology for everyday tasks, these techniques are not enough. As a result, treatments must be developed and implemented to counter the degenerative effects of long-term eye strain, which may eventually lead to headaches and farsightedness. This paper analyzes seven peer-reviewed journal articles centered around the effectiveness of each treatment on eye strain. Supplemental medications and ergonomic techniques show promising results for combatting dry eye and ocular pain, specific symptoms of eye strain. Studies evaluating the effectiveness of blue light glasses demonstrate conflicting results. Further research and implementation of these methods can decrease eye strain symptoms while improving concentration.
Eye strain is one of the most common ocular conditions faced by adults and students around the world . As of 2017, around 64 percent to 90 percent of computer users reported eye strain symptoms . Physiologically, these symptoms result from repetitive rapid eye movements between the keyboard, screen, and other documents . With more interactions taking place virtually because of the COVID-19 pandemic, addressing this condition is crucial for decreasing headaches and improving focus when completing tasks on screens. Many studies have only focused on treatment through minor modifications in a person’s behavioral tendencies, such as by following the 20/20/20 rule. This rule asks individuals to look 20 feet away from their screens for 20 seconds every 20 minutes . Since taking frequent screen breaks may not be helpful for severe eye strain, the purpose of this literature review is to evaluate the effectiveness of medications [1, 4, 5], blue light-blocking glasses [6,7], and ergonomic techniques [2, 3] in combating this condition. By evaluating these treatments, we can determine reliable methods for alleviating eye fatigue.
In terms of medication, omega-3 fatty acids (O3Fas) can reduce eye strain . Specifically, O3Fas treat patients with dry eye, which is a symptom of eye strain. When people stare at one location for extended periods of time, they often do not blink as much, which results in dry eye because of decreased eye lubrication . On a cellular level, O3Fas has been shown to increase the density of goblet cells, which lubricate the eye. The patients chosen for the study used a computer for more than three hours each day . While 120 patients received the O3Fas treatment, the remaining 236 patients received an olive oil placebo daily and their symptoms were evaluated. Each week, patients assigned a score between zero and three for symptoms such as blurry vision, dry eyes, and red eyes . At the baseline, 60 percent of patients had moderate dry eye symptoms in both the O3Fas and the placebo groups . By the end of the experiment, 70 percent of the O3Fas group and 15 percent of the placebo group were symptom free. In addition, Schirmer’s test was performed, which involves gently placing a filter paper onto the participants’ eyes and analyzing the cells found on this paper for tear production [1, 4]. A statistically significant improvement in dry eye symptoms was found in the O3Fas group compared to the placebo group, demonstrating the effectiveness of O3Fas in combatting dry eye resulting from computer vision syndrome . They can also improve epithelial cellular morphology in the eyes while decreasing tear evaporation rates, which ends up reducing eye strain symptoms. While this study analyzed the effects of O3Fas, it did not test for how the dosage of O3Fas affects an individual’s symptoms.
Besides O3Fas, researchers examined how the dosage of a particular botanical formula can decrease eye strain, while using a machine learning-based model to predict an accurate dosage for each patient . Botanical formulas are natural, plant-based ingredients and oils that are combined in order to treat or supplement a condition. This specific botanical formula is made of carotenoids, naturally derived pigments in plants that support eye health, as well as blackcurrant, chrysanthemum, zeaxanthin, and goji berry. These formulas are antioxidants and are known for their ability to absorb the blue light that typically radiates from visual display units. Researchers split the participants, who are each exposed to screens daily, into four groups. The three experimental groups ingested six, ten, or fourteen milligrams of the chewable tablet, while the fourth group received a placebo . Similar to the O3Fas study, this study also asked patients to take these tablets once daily for 90 days, while self-reporting how often they felt symptoms such as eye soreness and dry eye [1, 4]. In addition, both studies used Schirmer’s test to evaluate dry eye symptoms, which found that both the 10-milligram and 14-milligram groups had increased tear production [1, 4]. Researchers input the symptoms and dosages of 56 of the participants into their machine learning model, XGBoost. The study found that the optimal dosage is 14 milligrams for 39 individuals, 10 milligrams for 17 individuals, and zero milligrams for two participants . Researchers determined that the botanical formula significantly improves eye strain, while outlining the potential for machine learning to determine optimal dosages .
Bilberry extract (BE), another naturally-derived medication, has proven to be quite effective in reducing eye strain caused by acute video display terminal (VDT) loads, or devices with a display screen . BE is loaded with anthocyanins, which are known for their ability to decrease further visual disturbance and eye strain. The participants use VDTs daily and have eye strain symptoms. Over an eight-week period, the experimental group ingested 480 milligrams of BE per day, in contrast to the placebo group . The researchers evaluated their symptoms using the Critical Flicker Fusion device (CFF), which analyzes the frequency of a human eye identifying a blinking light as continuous [5, 6]. Lower CFF values correlate to less eye strain symptoms. This contrasts to the O3Fas and botanical formula studies that analyze the dryness of a patient’s eyes through Schirmer’s test [1, 4, 5]. Moreover, all three studies focused on patients with existing eye strain [1, 4, 5]. A self-reported questionnaire asked participants to rate the intensity of their symptoms on a scale from one to ten every week. Based on the CFF tests, researchers found a statistically significant lower CFF value, or less eye strain, for the BE group compared to the baseline .This CFF reduction was not observed in the placebo group. Participants in the BE group felt less ocular pain compared to the control group.6 The researchers argued that BE supplements can reduce eye strain caused by VDT loads, while further research can eventually analyze how BE works .
(a) Blackcurrant, (b) chrysanthemum, and (c) goji berry compose a botanical formula that can significantly improve eye strain .
Blue Light-Blocking Glasses
Medications are important treatments to consider, but there are many behavioral changes that may decrease eye strain symptoms too. One possible behavioral change is wearing blue light-blocking glasses in treating eye strain. Blue light is short-wavelength electromagnetic radiation, which ranges from around 400 to 500 nm in length, and carries one of the highest amounts of energy . There have been many hypotheses previously considered, which shows how blue light could potentially cause retinal damage, especially towards the aging eye. In fact, from studies in animals, increasing amounts of blue light exposure can increase the amount of cell apoptosis in the eyes . It is important to note that blue light is emitted by the sun onto Earth’s surface, but it is the excessive exposure to blue light from screens that can have negative effects . Based on these previous experiments, researchers aim to understand whether or not blocking blue light is effective in preventing eye strain and retinal damage by testing the effects of the blue light-blocking glasses.
Lin et al. assigned 36 participants into groups with the clear lens placebo, low-blocking glasses, and high-blocking glasses . Afterwards, participants performed a 2-hour task on identical computers in similar controlled environments. Researchers used the CFF device and a participant-reported survey to evaluate symptoms of eye strain and fatigue . The CFF depicted significantly less eye fatigue in the high-blocking group compared to the low-blocking and placebo groups. Participant surveys suggested that the high-blocking group reported feeling less pain and itchiness in their eyes after the computer task. However, there was no statistically significant correlation between blue light-blocking glasses and eye strain specifically, based on the participants’ self-reported scores for the intensity of their eye strain symptoms . Therefore, researchers determined that blocking large amounts of blue light may reduce eye strain from screen exposure, but more research needs to be done to determine if this effect is substantial. Awareness of these results can encourage the usage of blue light-blocking glasses to decrease eye pain and itchiness, while further studies can also evaluate its effects on eye strain and the specific amount of blue light blocked by different glasses .
Similar to Lin et al., Leung et al. also presented inconclusive results. Leung et al. compared the symptoms of patients wearing blue light-filtering glasses, brown tinted glasses, and a placebo, and found that while blue light filters decrease eye sensitivity, most participants could not detect these changes . A group of 80 computer users wore the lenses for two hours each day for around one month. The participants switched between the lenses during this time period. Researchers performed contrast sensitivity tests on the participants to see how accurately they can read a chart. Researchers use these tests to evaluate how accurately participants could read a chart in which the contrast of each black letter fades into the white background in small increments . This test found no significantly different contrast sensitivity results between the experimental and placebo groups. Based on weekly questionnaires, more than 45 percent of patients reported no changes in their eyesight or eye strain symptoms, while the majority reported no differences between the blue light-blocking glasses and the control lenses . Researchers concluded that analyzing the effects of blue light-blocking glasses is difficult. Spectral transmittance, which evaluates the amount of blue light blocked, showed that the glasses reflected around 10.3 percent to 23.6 percent of harmful blue light . Based on this discovery, researchers found that it is still important to wear these glasses to block the harmful radiation present between 400 and 500 nm in the blue light range, even when participants found no noticeable benefits. The differences between these two studies suggest how these various approaches could lead to similarly inconclusive results.
To compare the two studies, Lin et al.’s research included only 36 participants in a two-hour-long study in identical environments, while Leung et al.’s study had 80 participants and occurred over two months with no supervision [6, 7]. While Leung et al.’s study could analyze long-term effects of the glasses, Lin et al.’s experiment could only analyze the short-term benefits but in a controlled environment. Additionally, Lin et al.’s study only allowed each participant to try on one of the glasses, while Leung et al.’s experiment allowed participants to wear each one of the glasses [6, 7]. As a result, Leung et al.’s study eliminated differences in personal opinion between participants by only evaluating how one group responded to each of the variables. The outcomes of both studies showed how blue light-blocking glasses could relieve eye strain, although more research still needs to be done on this topic.
While there is conflicting evidence for wearing blue light glasses as a behavioral modification technique, the ergonomic approach shows more promise. To determine the benefits of ergonomics on computer vision syndrome (CVS), Mowatt et al. evaluated the prevalence of eye strain in students at The University of the West Indies (UWI) . Specifically, researchers analyzed how the angle of a computer screen affects eye strain. In this cross-sectional study, 409 students answered a questionnaire related to how often they use a computer, the severity of their eye strain symptoms, and the angle of their screens in relation to their eyes . The results depicted how severe eye strain occurred in 63 percent of the students who look down at their device compared to 21 percent of the participants who keep their device at eye-level . However, the data did not present a relationship between the prevalence of eye strain and the length of time spent on a computer. These results support the use of ergonomic practices, such as keeping a screen at eye-level, to reduce eye fatigue. Increased awareness of such behavioral modification techniques, especially by universities, can prevent eye strain in students . A similar study also uses a survey to analyze practices among individuals who work on computers daily.
Using surveys, researchers analyzed how ergonomics and symptoms of eye strain can be correlated. Office workers answered a questionnaire about eye strain symptoms and workplace conditions . Researchers found that a higher angle of gaze towards a monitor is associated with more CVS prevalence . In addition, looking upwards at a screen should be avoided as it results in muscular strain on the trapezius and neck muscles. This contrasts with the study at UWI, which determined that patients who looked down at their screens, at relatively large angles from eye level, tended to have more strained eyes [2,3]. Based on the results of both studies, placing the screen between eye level and at a small angle of 10 degrees downwards may be the best resolution. Moreover, using a monitor with a filter and adjusting the brightness of an individual’s screen to match that of the environment is correlated with less CVS . Although these results may seem to be solutions for CVS, they are based on surveys rather than controlled studies [2, 3]. Therefore, there is no definite causation between a certain ergonomic practice and eye strain.
When looking at all the possible treatments for eye strain from screen exposure, there are many different medications [1, 4, 5], types of blue light-blocking glasses [6, 7], and ergonomic techniques [2, 3] that can reduce symptoms. O3Fas and the presented botanical formula both show reduction in eye strain symptoms when evaluated with Schirmer’s test for dry eye [1, 4]. The BE study also showed promising results in reducing symptoms of eye fatigue through the CFF test, which focuses more on the temporal processing ability of the eyes . Though blue light-blocking glasses show positive results on the CFF tests and through measured spectral transmittance data, there are mixed results as to whether or not participants detect any changes in eye strain when wearing these glasses [6, 7]. Further testing can be done to evaluate the effects of blue light glasses, such as by examining a larger population or through a longitudinal study. Ergonomic techniques are correlated with less eye strain, according to recent surveys [2, 3]. Clinical trials in controlled environments can show more direct implications of ergonomic practices on eye strain from screen exposure. These treatments combined have the potential to reduce eye strain symptoms, leading to fewer headaches and improved concentration.
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