The Prevalence and Associations of Peripheral Retinopathy: Baseline Study of Guangzhou Office Computer Workers

Purpose To determine the prevalence of peripheral retinopathy and its associated risk factors among a sample of Guangzhou office computer workers. Methods A cross-sectional study of Guangzhou Chinese computer workstations and operators in different departments and units of the Guangzhou Power Supply Bureau, China, in 2016. Peripheral retinopathy was recorded and analyzed using a scanning laser ophthalmoscope (SLO; Optos, Daytona, United Kingdom) and slit-lamp microscopy combined with a three-mirror contact lens. Results The 1934 eyes of 967 subjects (513 females and 454 males) were included in this study. In total, 79.1% of the eyes were myopic in workers aged 20–29 years, 72.9% in workers aged 30–39 years, 62.2% in workers aged 40–49 years, and 43.4% in workers aged 50–59 years (p < 0.001). Most eyes had optic nerve crescents (81.3%). Various peripheral degenerations were found: 7 eyes (0.4%) had microcystoid degeneration, 40 (2.1%) had peripheral pigmentary degeneration, 87 (4.5%) had lattice degeneration, and 4 (0.2%) had snail-track degeneration. Nineteen (1.0%) eyes had paving-stone degeneration, 11 (0.6%) eyes had a retinal hole or tear, and 16 (0.8%) eyes had chorioretinal degeneration. Multivariate regression confirmed that greater axial length (OR: 1.18 (1.03, 1.35), p=0.012) and more serious spherical equivalent (OR: 0.82 (0.77, 0.88), p < 0.001) were significant risk factors for peripheral retinal changes. Conclusion Peripheral retinal degenerative changes were found in a larger proportion of younger computer workers than older ones. Myopia is occurring in younger and younger people, accompanied by peripheral retinal degeneration.


Introduction
e dramatic rise in computer use during the last few decades has raised concerns about the potentially deleterious health effects of increased "screen time" and associated shortwavelength (blue) light exposure. Increasing numbers of individuals are reportedly experiencing varieties of "computer vision syndrome" (CVS) [1,2], which includes irritated and dry eyes, eye strain/fatigue, red eyes, blurred/double vision, burning eyes, excessive tearing, light/glare sensitivity, headaches, slowness in changing focus, and changes in color perception [3,4]. However, the possibility that retinal changes occur in office computer workers remains to be confirmed. e blue component in computer screen illumination is relatively strong, but it is not nearly intense enough to produce acute retinal damage. Nevertheless, the potential exists for long-term, cumulative effects, including cellular damage arising primarily from increased oxidative stress [5,6]. e tremendous use of computers by staff members, technicians, and students at King Abdulaziz University (KAU), revealed by data from a previous study, has been accompanied by an increase in the number of visits to the University Medical Directorate (Services) for eye and vision complaints [7]. us, Chinese office computer workers are also likely to have a significant prevalence of CVS, with its associated loss of productivity and compromised quality of life. e aim of the present study is to describe the prevalence of peripheral retinopathy and its associated risk factors among a representative sample of Guangzhou office computer workers who operate the 976 computer workstations in the 32 different departments and units of the Guangzhou Power Supply Bureau, Guangdong Province, China. e study seeks to determine the prevalence and risk factors of computer use-related retinal changes in office workers, to provide useful information for the public on this ocular health issue, and to raise awareness about these issues among eyecare personnel.

Study Population.
is was a population-based crosssectional study conducted in Guangzhou, China, among the office workers who operate the 976 computer workstations in the 32 different departments and units of the Guangzhou Power Supply Bureau, Guangdong Province, China. All participants underwent a comprehensive ocular examination, which included best-corrected visual acuity, intraocular pressure (IOP) measurement by noncontact tonometer (TX-20; Canon Inc. Ltd., Tokyo, Japan), and slit-lamp anterior segment examination by noncycloplegic, A-scan ultrasound biometry (IOL Master; Carl Zeiss Meditec AG, Jena, Germany). e findings of fundus examinations, including posterior pole and peripheral retinal lesions, were recorded. e study was approved by the Institutional Review Board of Zhongshan Ophthalmic Center and adhered to the tenets of the Declaration of Helsinki. Written informed consent was obtained from all subjects.

Assessment of Refractive Error and Axial Length.
Each worker's refractive error was obtained with an autorefractor machine (AR-330A/310A; Nidek Co., Ltd., Beautshire, Japan). Subsequently, subjective refraction was determined by trained, certified study optometrists to achieve best-corrected visual acuity. e final subjective refraction result was used in the analysis. Spherical equivalent (SE) was defined as a sphere plus a half negative cylinder. Axial length (AL) was measured using noncontact partial coherence laser interferometry (IOL Master; Carl Zeiss Meditec AG, Jena, Germany).

Assessment of Peripheral
Retinopathy. All subjects were imaged with a scanning laser ophthalmoscope (SLO; Optos, Daytona, United Kingdom). If any suspicious peripheral retinopathy from the SLO was found, the observation from the dilated fundus examination with slit-lamp microscopy, combined with the three-mirror contact lens, served as the standard, and this was recorded on a predesigned form. e dilated pupil size was at least 6 mm, measured using a Haab's pupillometer. Standard digital fundus photography for the central fundus was performed for all subjects by the same observer.

Statistical Analysis.
e data were processed and analyzed statistically using STATA software (version 14.0; STATA Corp., College Station, TX). Data were expressed as the mean (SD). Demographic data and clinical measurements were tabulated for all participants and by gender. e significance of gender differences was determined using an independent sample t-test when the data were normally distributed, or with the Mann-Whitney U test when the data showed a nonparametric distribution. e significance of differences among different age groups was determined using analysis of variance (ANOVA) or the Kruskal-Wallis test. Univariate and multivariate logistic regressions were used to identify potential participant characteristics that were associated with retinal changes. e associated factors were evaluated using a generalized estimating equation model, taking into consideration the correlation structure between both eyes of each subject. For all the tests, p < 0.05 was considered statistically significant. e difference and bilateral test formulas were used to determine the minimum sample size.

Results
In this study, we included the 1934 eyes of 967 subjects (513 females and 454 males) with a mean age of 37.1 (8.3) years (range, 21 to 59 years). e mean uncorrected visual acuity of all subjects was 0.55 (0.44) (median, 0.40; range, 0.02 to 1.5), while the mean corrected visual acuity of all subjects was 1.16 (0.15) (median, 1.2; range, 0.1 to 1.5). e mean AL was 24.63 (1.40) mm, and the mean SE was −2.20 (2.55) D (median, −1.75; range, −15.0 to 4.5). Myopia was found in 68.9% of eyes. e mean computer use time was 8.0 (1.9) hours. No significant gender differences were noted for age, UCVA, BCVA, IOP, SE, C/D, computer use time, and working years. As expected, the AL was significantly shorter in females than in males (p < 0.001). Details of the demographic and clinical data of the study population are shown in Table 1.

Association between Retinal Changes and Potential Risk
Factors.
e analysis of potential risk factors included consideration of a possible relationship between retinal changes and age, gender, AL, SE, IOP, C/D, optic nerve crescent, and the mean computer use time per day. Logistic regression was conducted to assess whether these factors significantly predicted the existence of any peripheral retinal changes. e odds ratios are summarized in

Prevalence of High Myopia-Related Retinal Changes.
To the best of our knowledge, this study is the first to show explicitly the prevalence of retinal changes in office computer workers. We included the 1934 eyes of 967 subjects. e ALs were longer in male than in female workers, but no other statistically significant gender differences were noted for age, UCVA, BCVA, IOP, SE, C/D, computer use times, and working years (Table 1). ese results are in accordance with previously reported data in the literature [10], especially in populations from the United States [11,12], Germany [13], Australia [14], and Iceland [15].
Overall, 68.9% of the subjects in our study were myopic, and this prevalence was higher than previously reported in other studies. However, this may reflect the fact that the majority of the population in Guangzhou is ethnic Chinese and that the prevalence of myopia among this urban Chinese population is one of the highest in the world [16]. Interestingly, myopia is occurring at a younger age: 79.1% of  is higher prevalence of myopia prompted us to adopt the parameters used in previous studies that classified various changes as myopia-related retinal changes [17,18]. We found an optic nerve crescent (beta peripapillary atrophy) in 81.3% of the subjects' eyes. Many studies have been conducted to examine the prevalence of myopia-related retinal degeneration [19]. A high prevalence of optic nerve crescents was reported in myopic adolescents by Samarawickrama et al., who found an optic nerve crescent in 92% of eyes with myopia [20]. Again, this may be related to the sample size and the difference in subject populations, since the previous researchers recruited only a myopic population, whereas our study was only concerned with office computer workers [20]. Our results also demonstrated a lower prevalence of retinal changes when compared to previous studies that examined myopic populations. We found that more than 19.3% of our subjects had one or more peripheral retinal lesions, and that 0.8% of our subjects had a posterior pole chorioretinal lesion. However, these ratios are in accordance with previous studies. e peripheral retinal lesion noted most frequently was the WWOP type [21][22][23]. Peripheral retinal degenerative lesions, such as lattice degeneration and retinal holes or breaks, which are considered important risk factors for retinal detachment, were found in 4.6% and 0.6% of eyes, respectively, and the detectable rate of degenerative lesions in the peripheral retina was found more frequently in the temporal location than in the nasal location [17,24]. e highest number were located in the inferior temporal quadrant (46%), followed by the superior temporal quadrant (33.3%), and inferior nasal quadrant (16.1%), with the lowest number in the superior nasal quadrant (4.6%) ( Table 2).
Age did not appear to have a major influence, although it could be a factor affecting prevalence, as peripheral retinal changes were less frequently found in our subjects who were more than 50 years old (Table 3), as documented previously [25][26][27][28][29]. Our study also confirmed that the eyesight of the naked eye is better in older people than in younger people, which may be due to serious myopic problems in younger people. As yet, we do not know what accounts for this. However, the following two possibilities have occurred to us. First, this result could reflect an increase in the prevalence of myopia in younger and younger people, together with increased computer use, which has had the greatest impact on our lives in modern times [6,30,31]. Studies have shown an association between increased AL and the severity of myopia with peripheral retinal degeneration and an increased prevalence of peripheral retinal degeneration in myopia [17,[32][33][34][35].
e present study demonstrated that the incidence of myopia is higher in younger adults. A second possibility is that length of time using a computer declines as people age. Worldwide estimates indicate that 25% of computer users are already suffering from computer-related injuries. erefore, we find it likely that eye injuries are also possible, because (1) reading and visual work when using a computer leads to a change in the shape of the cornea, which may lead to the development of myopia [31]; (2) there is a significant positive association between playing video games for more than four hours per week and progression of myopia [31]. However, when comparing subjects aged 40-49 and 50-59, peripheral retinal degeneration was more prevalent in the older group. One of the most important reasons for the conflicting results in these studies may be the increased incidence of peripheral retinal atrophy in the elderly.
It is difficult to ascertain on the basis of previous studies how myopia alone affects the retina. erefore, we tried to   (Table 4). is may be related to the greater prevalence of myopia in young people than in the elderly.
Having reviewed the literature, Saw and colleagues suggested that chorioretinal abnormalities such as lattice degeneration are associated with refractive error and AL. is agrees with our findings, which showed that eyes with peripheral retinal degeneration had greater AL and more serious SE than did eyes without peripheral retinal degeneration. e aim of the present study was to determine the prevalence of peripheral retinal changes in ethnic Chinese office computer workers in Guangzhou. Our findings raise one important point: All participants were from the Guangzhou Power Supply Bureau, and most of them were senior intellectuals-a group with a known association with a high incidence of high myopia-and previous studies have reported peripheral retinal degenerative lesions in a considerable proportion of subjects with high myopia. As the myopic young adult population is at high risk of developing pathological myopia, we appeal for publications to pay more attention to the fundus health of young people, especially those with myopia. Health behaviour programs aimed at increasing outdoor time may also help to prevent incident myopia or to slow its progression.
Future research in this area should consider several issues, including adequate subject numbers and subjects from different departments. Our sample size was 967 subjects from 32 different departments, which was greater than our minimum calculated sample size (766).

Conclusion
Peripheral retinal degenerative changes and optic nerve crescents were found in a significant proportion of our subjects, who perform computer work in an office. Of these retinal changes, 0.6% were sight-threatening changes, and 19.3% were peripheral retinal changes. Myopia is occurring in younger and younger people, accompanied by peripheral retinal degeneration. With the modernization of society, we should pay more attention to the issue of myopia among young people.

Data Availability
All the data related to this article are in the manuscript and are available from the corresponding author on reasonable request.

Conflicts of Interest
e authors declare that there are no conflicts of interest regarding the publication of this paper.