It is not true , of course myopic persons have unhealthy retina & more chance of peripheral retinal degeneration. Once you get retina checked up by retinal specialist for these types of changes, if present future complication can be prevented by doing laser to those areas,most of the myopic people  have  normal retina, very few having peripheral retinal degeneration.

Hello Myopic patients may face some problems but not all patients have them Only a few patients develop them I am sorry but there is no way to prevent them except regular follow-up

It depends on how much ur myopia is....more than 6d is high myopia....u may have lattice degeneration with retinal breaks needing barrage laser in future ....only frequent yearly retina check up by retina surgeon would diagnose this and will help.also yes macula degeration may happen in old age...esp if ur myopia is progressive. ...nothing to worry just yearly screening and keep a vigil on sudden floaters or loss of field of vision which r danger signs of retinal tear and detachment. ...contact for further details thanks