Read and learn what you need to. The fact is that what most people need to improve is reading efficiency - that is, reading with a purpose, practicing skimming, looking for main ideas so that you can read them more carefully, and taking notes. For guidance on how to do this, come to the Office of Academic Support. Reading speed and efficiency is affected by the reading environment. Compare your reading environment to the one described on the back of this page.
Some students read rapidly and comprehend well, others read slowly and comprehend badly.
Whether you have good comprehension depends on whether you can extract and retain the important ideas from your reading, not on how fast you read. If you can do this, you can also increase your speed. Your concern should be not with how fast you can get through a chapter, but with how quickly you can locate the facts and ideas that you need. It is probably your brain, not your eyes, that slows you down in reading. Your eyes are capable of taking in more words that your brain is used to processing.