Hi! I wear glasses and would like some feedback/advice on whether the 21 inch and/or the 27 inch imac model would be better for reading text. I would be using the imac computer to also edit and store photos, do research and write documents, view videos, listen to music, check e-mail,etc. I am interested in the higher end 21 inch model and I3/I5 27 inch model. Thanks in advance for your help!