Wearing the mentioned power for your distant vision is advised if you are myopic to that extent for a clear vision
Near vision, the accommodation will reduce with age and you will start getting a positive add for near , so you would face a difficulty to read , and its not because of your corrective lenses, but you will be able to read without your glasses becoz you'll be making yourself towards positive
This is just presbyopia after 40 years of age
Next Steps
consult and get bifocals or progressive glasses