Depending on where you live, the coffee culture can be a big part of life. Whether you source and grind your own beans or delight in a Starbucks grande apple crisp oatmilk macchiato, once you’re hooked, that caffeinated zing is hard to pass over. In addition to helping humans wake up in the mornings for centuries, caffeine has been used for:
- Treating migraines and headaches
- Improving memory and mental alertness
- Help with weight loss and obesity
- Treating acute pain
- Treating bronchopulmonary dysplasia in newborns
- Lowering risk of type 2 diabetes
Researchers are now looking at how another use of caffeine can be added to the list – managing myopia.
What is Myopia?
Myopia is a type of refractive error of the eye, also often called near- or short-sightedness. People with myopia find that their far distance vision is unclear, while objects up close are easier to see. The higher your degree of myopia, the more quickly things become blurry as they move further away.
Myopia results when there is a mismatch between the length of your eyeball and its refractive power. This means that as light enters the eye, it is bent, or refracted, to a degree that is too strong. This results in the focal point of incoming light falling on a place in front of the retina. In order to see clearly, we want light to come to a sharp focus right on the retina. Eye doctors often put this another way – the length of the eye is too long for its power.
We treat myopia with minus-powered lenses, whether spectacles or contacts. People with myopia may also be suitable for surgical vision correction, such as LASIK or PRK. However, in relatively recent years, eyecare professionals and researchers have been asking another question – could we prevent or slow the development of myopia in the first place?
The Concept of Myopia Management
Having myopia isn’t just an inconvenience. It’s not just about not being able to see the board at school or the ball off in the distance. It is also a factor that increases your risk of several other eye diseases, some of which can have devastating consequences for your vision. These can include:
- Myopic macular degeneration
- Retinal tears and detachments
The impact of myopia as a risk factor for these conditions increases as the degree of myopia increases. For example, having short-sightedness between -1 and -3D increases your risk three-fold compared to someone who has perfect vision and no prescription (known as emmetropia). However, someone with a myopic prescription between -6 to -9D is at a 21-times greater risk than someone with emmetropia. That, in case you weren’t sure, is a lot.
So, in light of this, eyecare practitioners (predominantly optometrists), set out on the ever-evolving adventure that is myopia control, or myopia management. The aim of myopia management is to slow the development of short-sightedness in children so that when their prescription naturally stops changing with age, they will end at a lower degree compared to if they hadn’t been offered myopia management. Several myopia control strategies have been clinically demonstrated to reduce the rate of myopia progression in children, though the efficacy varies. These include:
- Atropine eye drops
- Multifocal spectacle lenses
- Specifically-designed myopia control contact lenses
- Specifically-designed myopia control spectacle lenses
All these treatments work by reducing the progressive elongation of the eyeball, which, as we discussed earlier, is what induces myopia. Research into how best to use these strategies is still ongoing. However, we know enough at this point for many optometrists around the world to have thrown themselves into myopia management with gusto.
But Wait, I Thought Children Aren’t Meant to Have Caffeine?
If you don’t want your kids bouncing off the walls til 3am (or later), then no, we don’t want to be serving up cups of Americano to our under-agers. However, in a study published last year, researchers found that topical eye drops of caffeine were able to protect against myopic eyeball elongation in the eyes of monkeys that had been given treatments to deliberately induce myopia. Some monkeys were also given treatment to deliberately induce long-sightedness (hyperopia). However, when the caffeine eye drops were administered to this group, it was found to have no effect, meaning the caffeine had a selective action on eyeball elongation (this is a good thing).
The study also noted that blood levels of caffeine in these monkeys was no greater than that after one cup of coffee in a human adult. Researchers were also careful to report that the monkeys treated with the caffeine showed no change to their behaviors (that is, there were no monkeys bouncing off the walls).
At the moment, a whole lot more research is needed before we can start dripping coffee into our children’s eyes. We don’t yet know the most effective dose for human children, the ideal dosing schedule, or the full risk profile of side effects.
What to Do in the Meantime
While we wait to find out whether single origin beans or Folgers instant coffee works better, keep an eye on your children’s eye health. If your child already has short-sightedness, be sure to keep up with regular visits to your eyecare professional to ensure his or her script is up to date and there are no other eye disorders developing. If your child is emmetropic and still has perfect vision, there is some evidence that spending increased time outdoors can be protective against developing myopia. For more tailored guidance on how to look after your child’s eyes and reduce their risk of short-sightedness and all the related complications, talk to your eyecare professional.