Also, don't make your audience read the slides. Reduce the amount of text you use (6-8 lines per slide, no more than 30 words per slide). The bullet points should be headlines rather than full-length essays. Use essential terms in sentence fragments and maintain your font size at 24 or larger. These will allow readers to skim through the slides quickly.
Make sure the typeface is large enough. In most presenting contexts, I find that any font size less than 24 points is too tiny to be read comfortably. I'd like to see the majority of the text at 28 or 32 point size, with titles at 36 to 44 point size. Anything smaller and you risk losing people's attention.
According to a study by the University of Illinois, here are the average letter sizes used in various documents:
8-point text: 5 1/4 inches (132 mm) high
10-point text: 7 inches (178 mm) high
12-point text: 9 inches (229 mm) high
14-point text: 11 inches (279 mm) high
16-point text: 13 inches (330 mm) high
18-point text: 15 inches (380 mm) high
20-point text: 18 inches (455 mm) high
22-point text: 20 inches (539 mm) high
24-point text: 23 inches (590 mm) high
26-point text: 25 inches (640 mm) high
A minimum font size of 24 points should be used on all presentations. Fonts such as Palatino, Georgia, Verdana, Tahoma, Arial, and Helvetica should be used in the document. Avoid using script fonts for readability.
Font sizes less than 18 points are difficult to read because your audience will need to zoom in to understand what you're saying. Any information given in small print should be repeated orally before the slide show begins or printed in a larger type size so that everyone can see it.
PowerPoint allows you to change the default font size for new slides by going to Home > Style > Font and choosing one of the many available options. It's best to start with something large like Times New Roman or Calibri and then go down from there. Use styles when necessary to add color, emphasize words, etc.
The best way to choose a font size that's readable and not too small is to use a digital ruler and measure the height of text at different locations on the slide. If the text is too tall or too short, it's not legible. The ideal length of lines of typed text is between 14 and 16 characters.
Text boxes on slides allow you to insert hyperlinks, quotes, and other elements that contain more information than can fit in a single slide.
In general, your font should be at least 28 points in size (or at the very least, 24). Your words will be unreadable if they are any smaller. The text should be at least 28 pt in size (it is 20 on the above slide). Depending on the typeface, you may be able to get away with using 24 pt (some are just designed larger than others). Avoid using 12 point or smaller fonts for medical presentations.
The reason why we need such large fonts is because doctors have to read your slides at a distance. If you write everything too small, you won't be able to see it easily.
Font sizes vary between types of documents but this is about how big ours are. A textbook page tends to have bigger fonts than this presentation, for example. And these are only some examples - there are many other factors that influence font size. For example, some fonts are designed to look good at small sizes while others don't really go down in scale well. Experiment with different sizes to find out what looks best on screen.
As you can see, we need large fonts for our presentations. This is because doctors have to read them at a distance from the screen. If you write everything too small, they won't be able to read it easily.