[paper]Digital eye strain:prevalence, measurement and amelioration
Digital Eye Stain (DES) have estimated prevalence of 50% or more among Computer Users. Symptoms fall in to 2 categories.
- due to accommodative or binocular vision stress
- due to dry eye
Symptoms are typical transient.
There are several available questionnaires to identify and measure DES. It also can be measured and identify by using objective evaluations of bellow parameters
- critical flicker-fusion frequency.
- blink rate and completeness.
- accommodative function and pupil characteristics
Sometimes the correlation between objective and subjective measures are not apparent.
Range of management approaches available for DES
- correction of refractive error and/or presbyopia
- management of dry eye
- incorporating regular screen breaks
- consideration of vergence and accommodative problems
DES and visual fatigue(VF) is used for Computer Vision Syndrom(CVS).
In 2016 UK adults typically spend 4hours 45mins per day staring at screens. USA it's about 5 or more hours
Most common symptoms associated with DES are,
- eyestrain (asthenopia)
- headache
- blurred vission
- dry eyes
- pain in the neck and shoulders
DES is very common problem 2016 Digital Eye Stain report with 10,000 US adults
- 65% total
- 69% of female
- 60% of male
- 73% who uses 2 or more devices simultaneously
- 53% single device
When computer use is 6 or more hours, contact wearers are more likely to affected(65% vs 50%)
Widely dissimilar diagnostic criteria for DED means the overall figures have a limited value. There are recent detailed recommendation for diagnostic methodology
- first symptom screening with ocular surface disease index or dry eye questionnaire(DEQ-5) instruments
- then objective clinical tests in in DED suspects
Measuring DES
subjective
- 10 item questionnaire created by Hayes
- six item visual fatigue scale
- Rasch based computer vision symptom scale
- validated questionnaire in english to evaluate DES in workspace
- self administered computer vision syndrome questionnaire
objective
- critical flicker fusion frequency
- the frequency which a flickering light is indistinguishable from a steady non-flickering light. reduced activity of the retina and/or optic nerve can cause this frequency number to decrease
- Blinking characteristics
- blinking helps to maintain normal ocular surface. before computer use mean - 18.4, during computer use - 3.6. incomplete blinks can also cause the dry eyes.
- Accommodative effects
- pre-prebyopes must be able to accommodate rapidly+smoothly and maintain a accurate response to perform near tasks comfortably. But when viewing computer displays this accomadation shows a lag.
- pupillary light relex and size
- increase of pupil size indicates visual fatigue.
Mangement of Dry Eye
use of lubricating eye drops reduce tiredness dryness and difficulty focusing. dietary supplementaion with omega-3 fatty acids blink training may help, (Increasing blink rate through use of an audible prompt signal every 4s during a computer task was not found to alter symptom score) blink efficiency exercise to address incomplete blinks may helpfull fix issures related to refractive error and fresbyopia - spectacles for screen use fix accommodation and vergence anomalies - frequent short breaks, blue light - exposure to blue light (400-500nm) can be harmful to the retina. melatonin involved in physiological ctrl of sleep. it's controlled by photosensitive retinal ganflion cells containing melanopsin, which has a peak sensitivity of approximately 482nm.
conclusion
usage is digital devices is norm today. this leads to DES. it's important eye care practitioners are well informed about this. DES symtoms are linked to 1. external - dry eye 2. internal - related to ameropia, accommodation or vergence problems. questionaires are valueble in evluating DES.