Digital devices in the workplace and home
While eyestrain associated with computer use has been addressed with various ergonomic suggestions, smartphones and tablets carry new recommendations that directly affect eye care providers. Our office workspaces are less likely to be cubicles with a desktop computer and a monitor on a desk. According to the Citrix Workplace of the Future report, by 2020, the average employee will access the company network from six different devices and one-third of employees will no longer work from a traditional office but rather at home, field sites or alternate locations.
Tablets are becoming more prevalent in the workplace, as well as at home. Tablets may be held at any angle for reading, but for typing, holding a tablet flat is bad for your neck. Holding a tablet completely perpendicular is bad for the wrists. A compromise is to hold the tablet at a 30-degree angle when typing or using the touchscreen. Ergonomists suggest accessory keyboards be used for laptops and tablets to allow for better positioning. This increases the working distance from the eye to the laptop screen and may elevate the height of the screen.
Smartphone ergonomists suggest holding the smartphone at eye level, with font size, screen resolution, brightness, and browser setting enlarged for eye comfort held at a distance of arm’s length. It has also been suggested that a smartphone is held while laying down, holding the phone over the face. Both of these positions strike me as being extremely uncomfortable to prevent you from working extensively on the device.
These recommendations may be more beneficial for posture, but they create significant problems with progressive lens wear. Traditional bifocals require the eyes to drop down into the bottom of the spectacle lens to view the printed reading material. Prolonged holding of the head upward to allow downward gaze into the progressive reading portion creates neck strain. Computer glasses with blue blocker coatings or “office lenses” directly address this shortcoming, but patients are frustrated with multiple pairs of glasses. Mentioning this option early, while discussing progressive lenses, may reduce their frustration and make them more amenable to purchasing multiple pairs.
Handhelds and ocular surface disease
In addition to causing postural problems, increased smartphone usage leads to increased surface disease. Reading reduces the overall blink rate, which is compounded by the eyes being open in primary rather than downward gaze. In addition to retinal damage reported with blue LED light exposure, LED exposure has been found to increase ocular surface disease in mice. LEDs of 630 nm, 525 nm, and 410 nm wavelengths were used to irradiate mice.
Tear Break up time of the blue wavelength group showed significant decreases compared with the control and red wavelength groups. Increased corneal fluorescein staining scores, corneal levels of IL-1β and IL-6, reactive oxygen species production in the DCF-DA assay, and inflammatory T cells in the flow cytometry was observed in the blue group, compared with the other groups. Authors concluded overexposure to blue light with short wavelengths can induce corneal oxidative damage and apoptosis, which may manifest as increased ocular surface inflammation and dry eye.
In another study, increased smartphone usage and short duration of outdoor activity were strongly associated with pediatric dry eye disease. Moon, et al, evaluated 916 children using slit lamp biomicroscopy and tear break up time as well as A questionnaire. The study was performed in Korea, which according to the authors, has the world’s highest smartphone use rates. The study considered video display terminal (VDT) use, outdoor activity, learning, and modified ocular surface disease index (OSDI) scores. DED was defined based on the International Dry Eye Workshop guidelines, and measured signs included punctate epithelial erosion, short tear break-up time, and a modified OSDI score. The rate of smartphone use was 65.1 % for 4th-6th graders, and 50.9 % for 1st-3rd graders. The dry eye group was more likely to wear spectacles, use a smartphone nearly 3 hours more than the control group, and spend less time outside.
Impressively, the dry eye was significantly improved when smartphone use was discontinued. Comparative analysis before and after discontinuation of smartphone use over 4 weeks was performed within the dry eye group. Punctate epithelial erosions improved from 93.3 to 0 % (P < 0.001). Mean tear break-up time improved from 10.00s to 11.33s (P < 0.001). OSDI score was decreased from 30.74 ± 13.36 points to 14.53 ± 2.23 points (P < 0.001). Overall, the rate of dry eye disease decreased from 100 to 0 % (P < 0.001).
Handhelds and Contact Lens Wear
In addition to causing problems with progressive lens wear and ocular surface disease, handheld devices may increase problems with contact lenses. Modern contact lens materials contain hydrogel and siloxane groups, allowing greater oxygen transmission. They are more hydrophobic, and stiffer than earlier contact lens materials for better handling by presbyopes. They also encourage lipid deposition and may suffer from poor wettability, reduced comfort levels, and mechanical complications.
The importance of digital devices and optical correction is reflected in current changes in the contact lens market. CooperVision recently introduced Biofinity Energys contact lenses for digital device users. This lens uses “digital zone optics”, multiple front surface aspheric curves over the entire optical zone, simulating more positive power in the center of the lens. It also boasts technology to increase oxygen transmission and lower the modulus to attract and bind water for increased comfort over the workday.viii
The demand for presbyopic correction is also increasing, as presbyopes have more trouble seeing their devices. The amount of commercially available presbyopic contact lens options has also increased to 15, with 7 daily options. A large number of daily options reflects the motivation of presbyopes to do as little as possible to see comfortably at intermediate and near tasks, and their willingness to pay for this correction.
Handhelds and Presbyopic IOLS
Modern technology has changed the goal for presbyopic correction. Rather than a 20/30 font at 40 inches, larger fonts, better resolution, and longer working distance have increased our flexibility for near correction. Although multifocal IOLs were originally intended and engineered for reading at 40cm, lower adds are now available. The ReStore lens (Alcon Laboratories, Fort Worth, TX) became available in lower add powers (+2.50D, +3.00D and +4.00D) and incorporated blue light filtering. The Technis multifocal family (Johnson and Johnson, Clearwater, FL) also became available in a range of lower add powers, including +2.75D, +3.25D, and +4.00D. The lens also uses a UV-blocking material. The Symfony (Johnson and Johnson, Clearwater, FL) target distance is more intermediate than 40 cm.
As our technology develops and near tasks change, our presbyopic treatment options must change. We need to educate our patients about these options early to promote acceptance and ensure when the correction is needed, they are well informed.
- http://ergo-plus.com/ergonomics-mobile-devices-workplace/. Accessed 9.17.2017
- http://lifehacker.com/5876996/youre-holding-it-wrong-heres-how-to-hold-your-touch-screen-gadgets-correctly. Accessed 9.17.2017
- http://www.ucop.edu/risk-services/loss-prevention-control/ergonomics/ergo-mobile.html. Accessed 9.17.2017.
- https://breakingmuscle.com/fitness/cell-phone-ergonomics-how-to-avoid-the-smart-phone-slump. Accessed 9.17.2017
Kuse Y, Ogawa K, Tsuruma K, Shimazawa M, Hara H. Damage of photoreceptor-derived cells in culture induced by lightemitting diode-derived blue light. Sci Rep. 2014 Jun 9;4:5223. doi: 10.1038/srep05223.
Lee HS, Cui L, Li Y, Choi JS, Choi JH, Li Z, Kim GE, Choi W, Yoon KC. Influence of Light Emitting Diode-Derived Blue Light Overexposure on Mouse Ocular Surface. PLoS One. 2016 Aug 12;11(8):e0161041. doi: 10.1371/journal.pone.0161041. eCollection 2016.
Jun Hyung Moon, Kyoung Woo Kim and Nam Ju Moon. Smartphone use is a risk factor for pediatric dry eye disease according to region and age: a case control study. BMC Ophthalmology. 201616:188 https://doi.org/10.1186/s12886-016-0364-4©.
Srinivasan, S. Today’s contact lens materials and Designs. Review of Optometry, 8/15/17. PP 36-45.