Zoom sharing portion of the screen as presenter - participants see slides as blurry

Hey @zoom83, there are several factors or reasons that can cause your shared screen to appear blurry on your participant's end. 

The most common reason is your internet connection. Please check on your internet connection when hosting your Zoom meetings. You can try to run a speed test as well to measure your internet's strength and stability. If you are connected through WiFi, I recommend that you use a wired connection instead. Check out support.zoom.us/hc/en-us/articles/201362463 for more WiFi configuration KBs to help you troubleshoot! 

Another reason is clicking on Optimize for Video Clip option when screen sharing. Please do not click on this when you are not sharing a video presentation. Enabling this feature when sharing a normal screen, pictures, etc. will cause the screen to appear blurry or distorted on your participant's end. This feature or option only works well with video clips. 

If the issue persists, I would consider uninstalling and reinstalling your Zoom app; here's How to uninstall Zoom.

Hope this helps!