The present study was based on a self-administrative survey including the OSDI questionnaire and conducted among young adults. The correlation of eye dryness with VDD use and contact lens wearing habits among young adults was assessed. It was found that the mean OSDI score of the participants who had been wearing contact lenses was increased to 34.36 from the value of 32.24 in non-wearer young adults. In addition to that, there was a statistically significant difference of OSDI scores was found between genders.
Higher OSDI scores in females compared with males were found in this cohort, and additionally, that dry eye disease was more common in females. There were several different studies in English literature about the difference in the OSDI scores between males and females [3, 14]. Some of these studies indicated that males had a higher OSDI score[14, 15], whilst others supported our finding with the outcome that showed females having higher OSDI scores. [16, 17]
Our study showed that the distance to the computer screen had a statistically significant enhancing effect on OSDI score. Participants using a computer at a distance less than 50 cm showed higher OSDI scores and there were several studies supporting our findings.[18] The optimum distance was indicated by several authors as approximately 60-100 cm away from the computer screen to minimize the risk of developing DED.[19, 20]
The use of a tablet or smartphone did not cause any significant change in OSDI scores of participants in terms of any parameter such as screen brightness, distance to the screen, angle of gaze, etc. This result might be related to using handheld devices in various gaze angles including small, most commonly, and high. It was shown that using a computer in higher gaze angles results in increased tear evaporation and therefore increased ocular discomfort symptoms.[21] Using devices in smaller gaze angles might be safer than using in high gaze angles. Yet, more investigation is required to be able to make comparisons. The studies conducted by Golebiowski et al. and Madudoc et al. also found no change in tear volume with the usage of tablets or smartphones, respectively. Although reduced tear volume is reported with computer use by many studies.[22, 23]
The majority of the studies in the literature indicated that contact lens use is a furthermost reason for DED. [5, 24–26] We found significantly higher OSDI scores among the females wearing contact lenses longer than three years compared with the non-wearers in our study. Present study had shown that CLWs using a computer for more than three years have significantly higher OSDI scores than those using a computer for less than three years. There were similar studies supporting our study with similar results [27] as well as some opposing studies stating no correlation between using a computer and DED.[24] We believe that using a computer over a long term resulted in infrequent blinking that resulted in insufficient wetting of the ocular surface. [19]
It was found that the indoor environmental factors such as the brightness of the workplace had an effect on OSDI scores of CLWs. Using a computer in a dark environment increased the OSDI score significantly so CLWs using a computer in a bright environment had a decreased risk of DED. However, there were very limited studies that were concerned about the brightness of the environment, one study pointed out that there was no association between the brightness of the environment and the OSDI scores. [28] On the other hand, another study stated that the weak lighting condition could affect the presence of complaints related to the CVS. [29]
Line of sight was stated as another risk factor that had a possible impact on the OSDI scores of CLWs. The current study showed that using a computer above the line of sight increased the OSDI score. Additionally, some studies lined up with a statistically significant relationship between OSDI scores and angle of gaze[19, 30, 31], although some limited studies asserted that there was no association between the line of sight and DED.[3] We believe that using the computer in a proper position is important to avoid DED. Due to the upper part of the ocular surface was protected under the effect of the upper eyelid in case of using a computer below the line of sight. [32]
This study was one of the most comprehensive studies in terms of the number of variables tested. In contrast to the extensive literature on computer usage habits, there is limited literature on handheld electronic devices assessed in the context of CVS. This study contributed to the literature by a detailed investigation of ocular disturbances related to both computer and handheld electronic devices among the young adults. However, one limitation of our study was that there was a disparity in numbers between the number of male and female participants due to nonhomogeneous gender distribution in this institute.