As obesity rates soar in the US and other countries, childhood obesity rates soar right alongside them. Numbers have largely leveled out in North America, but that doesn’t make them any less grim, as more than one-third of 6 to 11 year-olds were considered overweight or obese in 2012.
This is far from a quiet problem. Organizations have sprung up to raise awareness of what many people have termed an epidemic, while physicians and researchers alike have made it extremely clear that excess weight is unhealthy, regardless of age.
One area that doesn’t always receive as much attention though, is vision. Childhood years are formative ones for healthy eyes, and overweight or obese children are at greater risk of developing potentially permanent visual disorders. We’ll cover just a few of the reasons why aiming at healthier weights also means aiming at healthier eyes.
Nearsightedness, strangely, enough, has risen right alongside obesity. An increasing number of children and teens in the US are nearsighted and, unlike obesity, those rates show few signs of slowing. Unhealthy weight and myopia, while they don’t share an absolute connection, do have several factors in common and also have practical effects that can affect one another.
Myopia often first rears its head during childhood. Eyesight continues to develop for years after birth and, in some cases, it may give rise to nearsightedness. Myopia is generally caused by anomalous eye shape. Ideally, eyes have a spherical shape, allowing them to focus light from all angles directly onto the retina, a membrane at the back of the eye responsible for perceiving light. However, myopic eyes have a “rugby ball”, elongated shape. Consequently, light entering a myopic eye focuses on a point just slightly before the retina, causing poor vision at range.
Recent studies have found that one of the main contributing causes of myopia may lie in childhood exposure to natural light. Several different teams have confirmed the connection, and while they’re not entirely certain of the mechanisms behind it, the importance of receiving around 14 hours of natural light per week seems undeniable.
And, as you might expect, overweight children are less likely to receive those crucial hours. Unhealthy weight is often linked to increase screen time, or sedentary engagement with computers, tablets, phones, or video games. Whether you believe that those devices cause weight gain, or whether overweight children are more likely to turn to digital devices, the result is the same – children spending more time inside and potentially putting themselves at risk for developing myopia.
Among the most common outcomes of obesity is hypertension, or high blood tension. While once thought more as an age-related problem, pediatric hypertension is an extremely serious and increasingly common problem. Two to four percent of children are now estimated to be hypertensive.
Hypertension puts an enormous load on the entire cardiovascular system. When discussing vision, this becomes particularly problematic for small, delicate blood vessels in the retina. Over time, and with consistent, untreated hypertension, these can rupture and damage vision. Even worse, the optic nerve, responsible for communicating information from the eyes to the brain, can swell, also negatively impacting vision.
Juvenile diabetes has long been a synonym for Type I diabetes, also called juvenile-onset. Those terms may have be changed now, as Type II, long considered an adult-onset form of the disease, has skyrocketed as proportional cause of diabetes in children. To quote one article on the subject: “Until 10 years ago, Type II diabetes accounted for less than three percent of all cases of new-onset diabetes in adolescents. At present 45 percent of cases are attributed to it.”
The root cause behind Type II diabetes is complex and combines factors including genetics, race, and environment. However, a poor diet and obesity do increase risk of contracting the disease. Making the problem worse is that children have been shown to become resistant to insulin at a faster rate than adults, speeding their progression to a case of Type II.
For those with the disease, eye damage is a serious risk. Diabetic retinopathy occurs when small blood vessels in the retina (the same ones affected by hypertension) are stressed by spikes in blood sugar. Overtime, they can rupture, leak blood into the eye, and even begin to grow abnormally, permanently damaging affected retinas and impairing vision.
Asthenopia and Dry Eye
As mentioned above, there’s a close connection between being overweight and obese and time spent sedentary. Children with unhealthily high body weights are much more likely than their peers to spend time inside and engaging with digital devices, including computers, TVs, and mobile media.
That screen time can have severe effects on children’s eyes. Asthenopia, or eye strain, occurs when eyes are kept at a single, close focus point for too long, fatiguing small muscles responsible for accommodation. Uncomfortable, tired eyes result, as can headaches and even nausea. Dry eye is also a common factor, thanks to reduced blink rates in children watching TV or playing video games. Unpleasant at best, dangerous at worst, dry eye can bump the risks of encountering more serious problems, such as infection, or even keratoconus, a condition resulting from constant rubbing that actually deforms sensitive surfaces on the eye.
While childhood obesity can cause severe eye problems in and of itself, some of the worst damage it does is to the foundation of a healthy adulthood. Obese children are five times more likely to be obese as adults. Adult obesity contributes to many of the same disorders that childhood obesity does and brings a few new ones into play, including cataract, glaucoma, and age-related macular degeneration.