This can be a symptom of dyslexia. I have taught classes in special education in dyslexia in a pull-out program called R.I.P. I have also worked with students in regular classes with dyslexia on a consulting or tutoring basis. The overlays and rulers/cards are methods that work with many students. There are glasses that are made to help adults and children stop words from "swimming". Usually kids don't like them because they are noticeable, but a famous news broadcaster in Houston, Marvin Zindler, wore them and he couldn't say enough about how they changed his life. Other ideas are to change the color of the background on computers, tablets, Kindles, etc. I like black background/white letters, but I find students like yellow or grey backgrounds. They can also hold or tape their colored overlays onto their monitors. There are trained professionals that can help with overlays, such as colors, multiple colors or texture. Some students like 3x5 cards with a word size hole in the middle that helps isolate the word they are reading from all other words. We used to teach our students with dyslexia to write in cursive using all 4 learning modalities. They are lots of ideas out there that you can try. Hey--how about an expert tutor! Like me!