The global prevalence of DED ranges from approximately 5–50%; however, it varies with the definitions used and characteristics of the population being investigated [6]. Screen usage has become a significant part of our daily routines, and recent studies show that visual comfort problems associated with screens are real [7]. Therefore, IT students are more prone to developing DED due to continuous work in front of screens [7].
The current study found that the prevalence of DED was 47.7% among IT students in the district of Dera Ghazi khan. A web-based screening for DED disease among computer users also found the prevalence of DED disease to be 32.2% [14]. Our results show that the increased duration of usage of digital screens increases the prevalence of DED, yet their change was not statistically significant. In contrast, the study found that four or more hours of video display terminals are associated with 89.9% of DED cases [14]. In different population-based studies, the prevalence of DED among computer users has been estimated to vary from 25–75% [7]. A study in Pakistan evaluated dry eye syndrome and associated risk factors among computer users and found the prevalence of dry eye to be 28% [15]. A prevalence of 44.3% was also reported on symptomatic dry eye and its associated factors, and non-contact lens computer operators found that 68% of men and 73% of women reported dry eye symptoms [16].
In this study, there was no association between the age of subjects and DED syndrome. DED was, however, found to be significantly associated with the age group above 40 years in a study conducted in an adult population in South-West Nigeria [17]. Age distribution in the same study showed that all subjects fell within the age range of fewer than 30 years (327 subjects) [17]. This is imperative that the age of the subjects had no significant association with DED, as a larger percentage of the study population was less than 30 years.
The gender distribution of this study had a higher percentage of males and a lesser percentage of females. But there was no significant difference between the gender of subjects and DED syndrome. Another study reported no significant difference between gender and DED syndrome; most females with DED syndrome were post-menopausal [18]. Females included in this study were not among the post-menopausal group [18]. In this study, it was noticed that a longer time spent on the computer predisposed subjects to DED syndrome; again, this change was not statistically significant [18].
Long-term use of computers causes instability in the distribution of tears on the ocular surface, which could lead to evaporation of the tear and develop evaporative DED syndrome [19]. A study also reported that working on the computer for the long term affects tear film stability and quality of tears, leading to lower values of TBUT and eventually leading to DED syndrome [20]. Artificial tears, herbal eye drops, polysorbate 0.5% - optizen, and tetrahydrozoline 0.05% - Visine povidone 2% preservative-free eye drops have been prescribed to alleviate the symptoms related to DED [21]. In our study, the participants who used the eye drops had less DED frequency than those who never used them. And the use of eye drops was significantly associated with less frequency of DED. These eye drops rewet the ocular surface, contribute to tear volume, and thus, decrease symptoms of ocular tiredness, dryness, and difficulty in focus, thus improving dynamic visual acuity [22].
In this study, the most common ocular symptoms were a burning sensation, redness of eyes, watery eyes and foreign body sensation (eye grittiness and scratchiness). Burning sensation of the eye was also reported among 33% and 32% in a study conducted in Karachi [15] and India [11], respectively. Another study reported relatively less prevalence of burning sensation as experienced by participants [23]. A study reported redness, burning sensation, headache, and DED symptoms among computer users [14]. Another study reported that the most common visual problem was a burning sensation and dryness [4]. TFOS report also indicated headache, fatigue, tiredness, burning of the eyes, and dryness as the most common symptoms [24].
The current study has several limitations. One of the limitations is the smaller sample size and the subjective method of DED diagnosis. This study was limited to English-speaking subjects, with a vast sampling bias affecting the generalisation of study results. Additionally, the current study was geographically limited and hence underestimated the entire population of Pakistan. Risk factors such as contact lenses and screen time are more prevalent among the literate population, and therefore, this prevalence might be an overestimation of the targeted population.
The current study was the first cross-sectional study investigating the prevalence of DEDs to be 47.7% in Pakistan. The findings of this study may raise awareness about DED disease among users of digital screens. We recommend future studies on a population with a large sample size and the use of an OSDI questionnaire combined with objective measurement of DED tear film break-up time and Schirmer’s test.