It is a common misperception that eye strain, say from using a computer monitor or from "reading a book in the dark" can damage the eyes. Although it is the case that eye strain can cause some transitory fatigue symptoms, such as double or blurry vision, there is no scientific medical evidence that it leads to permanent eye damage. Regardless, it's a good idea to discuss this with your eye doctor
It is much more likely that your eyeglasses
prescription has changed over time as part of the normal natural history of your nearsightedness. It is very common for the eyes to continue to change in size and shape a bit from year to year, especially in the first several decades of life. In other words, it is totally normal to need to have your prescription increased a bit year after year. Eventually, this process does tend to slow, and it is not related to your computer use.
Again, it would be a good idea to discuss this issue with your eye doctor, and to keep your regularly scheduled eye appointments. The best way to treat computer related eye strain is to prevent it, and the best way to prevent it is to make sure that your eyeglass prescription is always up to date.