Dangers of Excessive Near Work: Dangers of iphone, ipad, computers
March 31, 2017
Dangers of Excessive Near Work: Dangers of iPhone, iPad, Computers, Excessive Reading
More and more research is showing that excessive near work, even reading, increases the length of the eyeball which leads to myopia. Myopia, meaning nearsightedness, or a “-” in front of the Rx, in turn leads to stretching of the inner layers of the eye such as the, retina, vitreous, and choroid. This in turn can lead to vitreous changes, such as floaters, posterior vitreous detachment, retinal holes, tears, and retinal detachment. Myopia also increases the risk of glaucoma (nerve damage which can cause blindness) and cataract.
Excessive near work also increase the risk of Computer Vision Syndrome, chronic dry eye from the loss of meibomian glands. When we stare at the computer or iphone or our books and do not take breaks and look away and blink, a cycle of inflammation is set off that leads to devastating consequences in certain patients.
Each blink forces the eyelids to push molecules of meibomian gland oil out of the meibomian gland. When we do not blink or blink partially, the oil is not drawn out as often. This can lead to a backup of oil which can make the gland malfunction and in some patients disappear completely. This in turn can lead to chronic dry eye and chronic eye pain.
Thus there are 2 key issues going on with excessive near work:
A. The constant focusing of the eye causes the eye ball to grow leading to:
1) Myopia which can then lead to
2) PVD: Posterior Vitreous Detachment
3) Retinal Holes
4) Retinal Tears
5) Retinal Detachment
B. Constant focusing usually means you blink less; blinking less or partial blinking decreases the pressure placed on the Meibomian Gland to “milk-out” of its oil. This leads to:
1) Clogged meibomian glands
3) Chalazion (chronic styes)
4) Meibomian Gland Dysfunction: where the oil gets too thick and does not come out as it should
5) Loss of Meibomian Glands which can lead to:
6) Chronic Foreign Body Sensation
7) Chronic Redness, irritation, reflex tearing of the eye
8) Loss of quality of vision
9) Loss of vision from scar tissue on the cornea from chronic inflammation.
PLoS One. 2016 May 3;11(5):e0154671. doi: 10.1371/journal.pone.0154671. eCollection 2016.
Near Work Related Behaviors Associated with Myopic Shifts among Primary School Students in the Jiading District of Shanghai: A School-Based One-Year Cohort Study.
To investigate the characteristics of various near work related behaviors among primary students and their associations with changes in myopia related ocular biometric parameters during one-year of follow up.
A school-based sample of 4,814 primary 1st to 4th grade students aged 6-10 years old were selected by cluster randomization based on probability proportion to size in 2013. At baseline, students together with their parents filled in a self-administered questionnaire on 9 aspects of near work related behaviors and some important covariants of myopia. A comprehensive set of eye examinations including axial length (AL) and cycloplegic refraction was conducted both at baseline and one year later.
With the grade level increase, students did increasingly better at finding various ways to have an eye break, but they were increasingly likely to continuously do long-time near work without an eye break. Keeping a reasonable eye distance and correct hand posture for reading, writing, or watching TV became worse for the first time before grade 2, but then became better at grade 3. In contrast, selecting appropriate lighting environments or situations and keeping a balanced diet became better for the first time before grade 2, but then became worse at grade 3. At one-year follow up, the mean AL increased by 0.32 ± 0.35 mm, the ratio of AL divided by the mean corneal radius of curvature (AL/CR ratio) increased by 0.032 ± 0.054, the myopic spherical equivalent (SE) increased by -0.51 ± 0.51 diopters and the incidence of myopia was 16.0% (237/1,477). After controlling for the confounding effects of parental myopia, student’s age, gender, height, daily near work time, daily outdoor activity time and all of the other near work related behaviors, keeping a reasonable distance when reading, writing and watching TV was associated with elongation of the AL [standard coefficient beta = -0.062, P = 0.004], a change in SE [beta = -0.072, P = 0.020] and incident myopia [adjusted odds ratio (aOR) = 0.90, 95% confidence interval (CI): 0.84-0.96]. Selecting an environment with adequate light for visual comfort to read and write was related to elongation of the AL [beta = -0.039, P = 0.034] and increase of AL/CR ratio [beta = -0.030, P = 0.048]. Also, not continuing to do near work for more than 30-40 minutes without an eye break was related to increase of the AL/CR ratio [beta = -0.028, P = 0.044] and a change in SE [beta = -0.064, P = 0.023].
Various near work related behaviors changed according to grade level in primary school students. Independent of hereditary factors, daily near work load and outdoor activity, near work related behaviors such as keeping an inappropriate eye distance for near work, selecting inadequate lighting environments, and continuing to do near work without an eye break were risk factors for myopic shifts.