Devices and Vision – Two Perspectives

Optometry Times posted the following article as part of the Back-to-School Vision Awareness blitz that occurs every August 23, 2022. Like the pervasive use of the tired ‘20-20-20 Rule‘ to alleviate visual strain, the VisionMechanic took umbrage to the piece for a variety of reasons, and they are laid out below. Vision, as critically important to child development as it is, deserves proper, clear, respectful representation in the media. Broad sweeping statements with no grounding can have lasting impact on readers, but also on the profession if the statements are notably inaccurate or misleading.

Optometry Times® editor Kassi Jackson speaks with Valerie Kattouf, OD, FAAO, chief of Lewenson Pediatric and Binocular Vision Service and associate professor at the Illinois College of Optometry, on the effects of digital media on the pediatric population.

Jackson: So let’s talk about children’s eye health. According to data provided by the World Health Organization, vision impairment and blindness affect 2.2 billion people worldwide, and 90 million of those affected are children. So why is children’s eye health so important?

VisionMechanic: WHO tracks blinding conditions, and to a lesser extent ‘low vision’ concerns. As a rule, WHO does not include visual functional deficits in its tallies, yet these are the issues that plague pediatric patients by far the most. These include refractive conditions (Hyperopia, Astigmatism, Anisometropia – myopia is not the most severe of these, it is in fact the least severely impacting on the pediatric population).

Kattouf: Well, I think one of the things to consider is that, you know, vision is a primary input. It’s an input method that influences a child’s learning, their development, their demeanor, their stamina; it has an effect on everything. 

And I think sometimes the misconception is that vision is just about clarity. Clarity is just one part of vision; we need the visual system to be functional, we need it to be flexible, and we need it to be efficient. And there’s so many parts that go into that.

VisionMechanic: Vision is a primary input but also a primary output. There is no arguing vision is central to human motor, cognitive, and emotive functioning. We’ll agree that vision is complex, multi-faceted, and that sight, or ‘clarity’, is just one element. 

Jackson:  Digital media can affect pediatric development. How do you define digital media?

VisionMechanic: A broad and leading question with nothing to back it up. 

Kattouf: So digital media is pervasive. And in today’s world, it’s everywhere. So digital media are your phones, it’s your tablets, its computers, its TVs, it’s the DVD player in the car. It’s all of those things. And I really think if—especially parents—were to look at it and add up the hours, it’s much more exposure for your child than you even think.

VisionMechanic: This is a heavily biased statement with nothing to back it up. The use of ‘exposure’ suggests a toxic risk which in reality does not exist. 

Jackson: What type of effect does digital media have on children’s visual system specifically, looking at focusing on accommodation?

Kattouf: When I talked about visual function, we have the focusing system which has to function readily, we have the eye teaming—or binocular vision system—that has to function. 

What parents have to realize is, it’s really the phones and the tablets and the computers and the hours spent here that we have these near demands, we are up close on things. And to be honest, our bodies weren’t meant to do that; our visual system wasn’t meant to do that. 

VisionMechanic: The concluding statement above has no basis in fact. Indeed, some people, nearsighted people, ARE ‘meant’ to do that. I’ll add the use of the teleological argument, that our bodies were intended to function in one way in particular, is unsupportable. In fact, the human ‘is designed’ or ‘meant’ to do a lot of things in a variety of ways in all sorts of conditions. Elsewhere, what our bodies were ‘meant’ to do is a matter of philosophy, not of Optometry. 

We all have a certain amount of focusing power—kids have a lot more than adults— it’s why when adults reach into their 40s, they need reading glasses, because we lose focusing power over time. So kids ideally have an immensely strong focusing system that should be flexible and efficient. But my goodness, we are just seeing a decrease in that today. 

So literally, the focusing system is a muscle and it gets worn down from too much near demand. If you were to walk around with a 10 pound weight in your arm all day long with your bicep curled, your bicep will be tired. It’s the same thing. Kids are on these devices excessively, and it wears down their focusing system.

VisionMechanic: “focusing power” is misleading. Adults and children maintain roughly the same muscle power, but the crystalline lens becomes less pliable in time. The fact is children have greater accommodative range but they still must exercise effort to use it. The notion that muscles get worn down is misleading, this simply does not happen. Muscles fatigue, perhaps this is what is meant. There is no evidence to show kids use of devices ‘wears the focusing system down’. Again, to a myope, this sort of activity will be perfectly comfortable for hours on end. Not so much for the hyperope or astigmat, and others. There is no evidence we are seeing a ‘decrease in (focusing power) today’. There is another grand generalization about kids being on these devices ‘excessively’. 

Jackson: And how is children’s biocular vision impacted by digital media?

Kattouf: Binocular vision is your eye teaming skills; it’s how well your eyes work together. So yet another system that has to be efficient and flexible, it gets worn down. 

VisionMechanic: What is it with all these eyes getting ‘worn down’? It is not even clear what is being discussed here. 

But I think one of the main things to realize is that binocular vision development, it starts in the brain. And there are a lot of neurological concerns that screen-based activities stimulates visual processing a lot more than it does sensory processing. 

So all of that development is affected number 1 by how young we started our kids with an extensive use of devices, and then the excessive use of those devices as well. 

Whether it’s focusing or it’s eye teaming, they both get worn down.

VisionMechanic: Will stop talking about vision getting worn down. If you’ve read this far, you understand. ‘Binocular vision (BV) development starts in the brain’ – this is a dubious point since retinal tissue is brain tissue, since the terms are not well defined. Indeed, BV cannot occur sans interaction with the environment. It’s unclear which neurological concerns are being considered here. There is a good point made about the fact that time spent on devices is time NOT spent on multi-modal multi-experiential motor-based activities, but vision-based activities are not going to be inherently toxic or disadvantageous. The points are made that media at an early age may pose a problem and that excessive use of media may be a problem. These points can be made elsewhere in pediatric psychology, ed-psych, but the VisionMechanic suspects the developmental concerns re: eTime is more related to what is not happening while children are using devices rather than any intrinsic danger to the devices themselves or their use. Consider for example the dopamine reward cycles that define most children’s games. 

Jackson: And what about ocular motor dysfunction?

Kattouf: Ocular motor dysfunction is tracking. So that’s an issue with tracking, you know, kids who have difficulty reading, focusing with attention, they can have ocular motor or tracking problems. 

VisionMechanic: Oculomotor dysfunction, OMD, is much broader that ‘tracking’ and includes vergence, accommodation (focusing), fixation, pursuits. 

A lot of screentime doesn’t always facilitate great fine motor development, and ocular motor skills or a fine motor skill.

VisionMechanic: This is a bit of a nonsense statement logically, and adds little clinically. 

Jackson: In your expert opinion, in what way does digital media attribute to the development of pediatric myopia?

VisionMechanic: It appears Jackson means ‘contribute’ rather than attribute. 

Kattouf: So myopia is nearsightedness.  …

Number 1, it’s visually burdensome; you can get holes, breaks, tears in the back of your eye or in your retina. So myopia is something we want to control; we don’t want to see that progression. 

VisionMechanic: The incidence of myopic retinal tears and degeneration are high compared to other refractive states, but remains very low in the general population. Myopia is not always a burden – for those working at near distances, low to moderate myopia can be a gift since it offers a relaxed visual state at near distance. 

When you have excess near demands, you are doing close work all the time—screens, tablets, computers—then you get excess accommodation or focusing, that actually increases the length of the eyeball, the axial length of the physical eye, and that increases myopia.

VisionMechanic: Near demand depends on refractive state. Myopes, it turns out, have the least strain at near distance. Working at near distance does not make a farsighted child nearsighted. There is no evidence to suggest near work causes elongation of the eyeball under normal circumstances. Accommodative strain has no impact on axial length.  

There are truly modifiable behaviors that affect the development of myopia. The more indoor time, the more time on screens. 

It’s very often an environmental factor that makes myopia progress over time. It’s proven statistically—through studies—that the more time kids spend outdoors—the less near demands they have, often with that, the less myopia develops.

VisionMechanic: It is true some environmental factors can have a role in myopic progression, but this is in extreme conditions or experimental conditions only ( Screens do not cause myopia. By far, myopia is determined by genetic factors. Environmental factors will have a small effect overall in normal conditions. 

Jackson: Moving beyond eye functions, what role does digital media play on children’s overall development and their self esteem?

VisionMechanic: This is where the VisionMechanic gets off the bus. While he does have a background in child psych, it’s inappropriate to engage in this discussion in a serious way in the context of Optometry Times. 

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