We're living in a world where 2.2 billion of us have our vision going on a blurry trek, according to the World Health Organization. Shocking, right? And here's the punchline - approximately half of these could have been equipped with preventative measurs to keep their HD vision intact or they just haven't had a decent chinwag with their good ol' eye doctor yet.

That's why we have eye-exams playing the white knight in this story. The American Academy of Ophthalmology (AAO) is all for you sitting down with an ophthalmologist for a comprehensive exam once in your twenties, twice when you hit the big three-oh, and once more when you're four decades old. This is the time when your body might start pulling tricks, and unexpected health issues or vision changes might sneak in. If you're sailing on the age boat of 65 or older, an annual or biannual visit to the ophthalmologist should be marked on your calendar. If your family's medical history looks like the plot of a Stephen King novel, or you've had troubles with eye diseases in the past, you might need to see your eye doctor more often.

Eye exams are a treasure trove for identifying progressive eye conditions like glaucoma, the ninja disease that shows up without a warning sign and a leading cause of blindness for anyone older than 60. Luckily, getting an early jump on glaucoma treatment can prevent a March-of-Dimes blindness outcome. Similarly, age-related macular degeneration (AMD), a notorious cause of vision loss, often tiptoes in without any symptoms but can be flagged down during a routine eye check-up.

So yes, eye exams are important. However, certain eye symptoms demand an immediate checkout-counter medical attention. They don't wait in line for your routine checkup. We've rounded up 10 symptoms for you to keep an eye out for (no pun intended), and how to decide if you need to call in the eye cavalry.