Should i be worried if my 50 plus year old father sees double vision after playing on his tablet pc?

Probably not: True double vision (seeing two of the exact same image) is usually only worrisome if it is present all the time. Extended visual tasks can cause eye strain, headache, extreme blurring, or even in some cases actual double vision, but in these cases, the symptoms are brief and temporary. Taking a break for a few minutes every hour can help prevent the or alleviate these symptoms.

Depends on : If double vision is with one eye or the two together. It would be a benefit to get him in for an eye exam.