Odds of Getting In
Basically, if you have the few prerequisites needed and are willing to go just about anywhere in the country, you have an excellent chance of getting a job as an orthoptist. What's more, over the next few years this field is expected to have average to above average growth rate across the U.S. at a yearly rate of 9.55% (source).
All this is to say that any passing curiosity you may have with poking at peoples' eyeballs to see what happens may have the potential to turn into a lucrative and interesting career. The basics for a healthy career are right there: eye defects are common in children and the elderly.
As the population ages, all healthcare related jobs will continue to grow, outpacing other jobs in terms of openings. You'll be just fine, future peeper prodder.