Tear Film Status in Smartphone Users Vs Non-Users: (an observational study)

Purpose: To observe the effect of Smartphone use on the tear film of users versus non users in a Tertiary care hospital, assessed by Schemer’s test.

Study Design: Prospective observational study.

Material and Method: The study conducted at LRBT, Teaching and Tertiary Eye Hospital, from January 2019 to June 2019 and included hundred patients from age ranging from 18- 30 years. They were divided into two groups of fifty patients of both genders. Schirmer test 1 and 2 were used to assess the tear film.

Results: Schirmer test 1 and 2 revealed a decrease in tear film level in group A as compared to group B.

Conclusion: Smartphone and electronic display devices have an adverse effect on the ocular surface, as well as the tear film level.

Keywords: Tear film, Smartphone users, Schirmer test, Dry eye, ocular surface symptoms

Living in this age, use of electronic gadgets, especially Smart phones, has become an integral part of our daily activities. The omnipresent vocational and non vocational usage, be it at work, leisure, on the go, e?mail, internet access, social networking and entertainment has become almost universal activity in the society mostly because of the widespread availability in the general population.[1] Smartphone usage differs with respect to region (urban and rural) and age (younger and older). According to a study done in 2013, the average time spent using a smart phone nearly doubled than with ordinary mobile phones resulting in many health issues by altering with sleep patterns and mental health.[2, 3] Recent literatures reported a correlation between ocular health and smart phone use.

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Basic and reflex tear film level is decreased in

smart phone users for more than six hours a day

for at least three years.

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One of the studies reported cases of transient monocular vision loss associated with smart phone use[4] and another study reported acute acquired commitant esotropia in young adults.[5] An excessive usage of smart phones affects the tear film and the ocular surface as reported in office workers who spent more than 4 hours looking at the screens, hence, experiencing severe ocular symptoms.[2-7] Another study reported that the blue light emitted from the smart phone screen has an adverse effect on the corneal epithelial cells in humans[8] and an over exposure to blue light causes the tear film to deteriorate and increase inflammatory marker levels and reactive oxygen species (ROS) production on the ocular surface.[9] Since the viewing of screens is not restricted to the computer at workplace only, the portability of smart phones is an added benefit which allows the users to view at any location for any length of time and is, therefore, associated with a reduction in blinking, resulting in dry eye symptoms.[10-12] Considering the number of hours being used to look at smart phone screens, the magnitude of ocular and visual symptoms are of notable concern when compared to printed material. Smart phones are hand held and so, the pattern of use, screen size, luminance, position of viewing and distance differs, along with alteration in accommodation. There is a noticeable reduction in the fusion convergence and receded near point of convergence. Blink rate and tear film instability are also adversely affected.[13] Furthermore, smart phone use is not restricted to adults, teenagers and older children, Vanderloo reported that pre-schoolers spend up to 2.4 hours per day watching electronic screens, and the difference in screen sizes may entail a small text to be viewed at a closer distance warranting an increased visual demand contributing to a variety of symptoms known as computer vision syndrome (CVS).[14] CVS, as defined by the American Optometric Association, is an integration of ocular and visual problems related to the use of screens, resulting in the lack of visual capability to perform screen related tasks comfortably. Visual symptoms including eyestrain, headaches, ocular discomfort, dry eye, diplopia and blurred vision may be experienced in 90% of screen users.[15] Another investigation on the effect of symptom causing conditions of asthenopia, the authors classified two broad types of symptoms. The first group included external symptoms, like burning, irritation, ocular dryness, tearing and was related to dry eye. The second group described internal symptoms including eyestrain, headache, diplopia, blurring, caused by refractive, accommodative or vergence anomalies. Round the clock persistent use of smart phones is pushing manufacturers to produce brighter screens for the ease of reading, based on shorter wavelength blue light, increasing the probability of visual damage when used for a longer length of time, as well as causing dryness in the eyes due to decreased blinking and wider opening of the palpebral fissure as a result of horizontal gaze causing an increase in evaporation through exposed area.[16]

 

METHODOLOGY

 

This observational study was conducted at LRBT Tertiary Teaching Eye Hospital, Karachi, from January 2019 to June 2019 and included 100 patients divided in to two groups. Each group included 50 patients of both genders with age ranging from 18 to 30 years, mean age was 24±2.6 years. The study was approved by institutional ethical review committee. After explaining the study procedure, informed consent was obtained from all the patients. Group A included patients who were habitual of using smart mobile phone for at least six hours a day since last 3 years. Group B included 50 patients of the same age group, but they were not smart phone users. We took complete history and those people with history of working in a smoke polluted environment or any systemic disorder which can affect the tear film level; those patients were not included in this study. Following the history, all patients of both groups underwent complete ophthalmological examination with special emphasis on the tear film level. We used Schirmer test 1 (without anesthesia) and 2 (with anesthesia) in all patients of both groups and noted the results on a study proforma. Procedure of Schirmer test performed involved measuring the amount of wetting of a no. 41 Whatman filter paper (5 mm wide and 35 mm long) by folding 5mm of one end and placing it at the junction of the middle and outer third of the lower lid without touching the cornea and lashes. Patients were asked to close the lids and the amount of wetting from the fold was measured after 5 minutes and noted on the proforma. The rationale of this study is to highlight whether the use of excessive smart phone in our daily routine is hazardous for ocular health with respect to ocular surface discomfort.

 

RESULT

 

This study included 100 patients, divided in to two groups with an age range of 18 to 30 years. Tear film measured by Schirmer test was done in the patients of both groups. Results of group A shows 8 ± 0.6 mm wetting in Schirmer test 2 and 4.6±0.5 mm wetting in Schirmer test 1 (without anesthesia), whereas in group B shows 10.5 ± 0.7 mm in Schirmer test 2 (with anesthesia) and 6.7 ± 0.5mm wetting in Schirmer test 1. Group A, also complained of an increased incidence of grittiness and ocular surface discomfort owing to their persistent smart phone use. Group B patients complained of ocular discomfort and grittiness but not as much as Group A patients.

 

DISCUSSION

 

With the preponderate availability of Smart phones in the general population and its integral role in everyday life, various adverse affects on the ocular health have been reported. In this present observational study Smartphone usage was significantly shown to affect the tear film of users, as measured by the Schirmer’s test. Millions of people suffer from screen related ocular problems, the severity of which is increasing with prolonged use.[17-18] Smartphone users who spend more than 4 hours using a screen display experience more adverse symptoms.[19] Despite the duration of smart mobile device use reaching an alarming rate in the present generation, long-term visual effects of chronic use have not been extensively investigated.[18] Studies done previously showed that the duration of Smartphone use per day was associated with a higher prevalence of dry eyes and ocular symptoms.[6, 20] A continuous usage of a digital screen for more than 4 hours can significantly increase eye discomfort by decreasing the blink rate and increasing the accommodative effort.[21] Another study looked at the distances used for viewing a mobile device and reading books and found out that the distance preferred for mobile viewing was shorter (36.2 cm), hence requiring more accommodation and convergence, than for the books (40 cm).[22] Blinking helps with the tear secretion; by spreading it over the ocular surface, evaporating and draining which necessary for the maintenance of normal ocular surface.[23] Nakamori perceived a mean rate of 22 blinks/ min among office workers under normal conditions, reducing to 7 blinks/ min when working on electronic display. One more study distinguished two defined levels of cognitive demand, both on a new era tablet computer and hard copy printed versions.[24] Varying cognitive demand leads to a greater reverberation on blink rate than presentation format. Mean blink rates for the less demanding tasks were 8.34 and 9.06 blinks/ min for the tablet and paper presentations, respectively, reducing noticeably to 7.43 and 6.67 blinks/min, respectively, for higher demanding tasks.[20,25,27] Uchino observed that digital screen users had short tear break up time and increased corneal fluorescent staining, despite normal lacrimal function.[1] Increased blinking intervals while gazing is a causative factor in digital screen associated dry eye due to excessive evaporation of the tear film.[21,22] Decreased blinking, frequent incomplete eye closure and increased ocular surface exposure may interfere with the delicate homeostatic balance of the ocular surface system, causing subjective symptoms and tear instability.[26,28] A study conducted, showed significant tear film dryness after 1 hour and 4 hours of Smartphone use.[29] Another study found no significant association between Smartphone addiction and dry eye disease.[30] Whereas, a study done on Fifty- nine volunteers (age, 38.16 ± 10.23 years; male : female = 19 : 40), who were exposed to smart phone screen for 1 hour, showed significant visual discomfort after 1 hour in the form of tired eyes, sore/aching eyes, irritation, watering and burning sensation.[31] CVS is expected to be more severe after Smartphone use owing to the smaller screen, viewing at a closer distance and lower position. The blink rate in a healthy person is approximately 20 blinks per minute though it varies person to person. Smart phone use causes a reduction in the blink rate.[23,25] This study did not asses all the confounding factors due to the multifactorial changes on the ocular surface, owing to Smartphone use. Awareness of Smartphone related tear film and ocular changes is needed in clinical practice to enable a better understanding of the factors leading to ocular discomfort as well as their management of ocular issues due to excessive Smartphone use. Schirmer test results in this study were significantly worse in individuals using Smartphone. Additionally, the Smartphone group had ocular fatigue, burning, and dryness associated with the infrequent blink rate and frequent incomplete eye closure during Smartphone use.

 

CONCLUSION

 

In this study we found out that both basic and reflex tear film level is decreased in smart phone users using devices for more than six hours a day for at least three years. The basic change in pathophysiology of tear film reduction is not the domain of this study since it is only observational. Due to a dearth of specific literature assessing the impact of Smartphone use on tear film and ocular surface owing to the rapidly evolving and diversity of technology, larger scale trials are recommended to establish the data and highlight the change in pathophysiology

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