Unfortunately, the SAAF and SANDF are not proactive in interacting with potential recruits via this website and social media ... a great opportunity lost.
I cannot speak on behalf of the SAAF, but they do state that you must have 6/6 vision, in other words, not have need of spectacles, contact lenses or laser 12 correction. I would imagine that Ortho-K will fit into this category and is not allowed.
Joining the SAAF and being a military pilot in South Africa must be a passion, something you want to do above all else. You certainly will not be doing it for the money and hours will be built up slowly compared to those doing commercial flying. However, those hours you do fly will be the best, exhilarating, strenuous, exhausting and stimulating hours you'll ever fly! Hours for hour, the military hour will be provide far more experience than that obtained flying commercially for any young pilot.
You want to be financial secure? Find another profession.