It is unusual to see myopia worsening at your sister's age, but reasons could include diabetes with uncontrolled glucose, onset of nuclear cataracts, and degenerative myopia with progressive axial growth of the eye and retinal degeneration. Your sister should see an ophthalmologist for a complete exam, including dilation. She may also need to see a retinal specialist.
Thank you for your advice. She went to ophthalmologist and retinal specialist. He said her retina is very thin and dystrophyc. The only recommendation for the moment it was the retina nutrition with vitamin tablets such blueberry and avoiding the weight and hot shower. The advancing of the myopia shall be seen only on the next visit after several months or one year. Does exist any other option for feeding the dystrophyc retina? thank you to a comment.