I have an eye problem, so I want to make the "today line" in my Gantt chart to be larger and bolder. Is there any way to do so?
Right click the mouse over a blank space on your gantt graph, choose "gridlines...", highlight "current date" and define the line color and type. I usually make it a red continuous line. Unfortunately, it is not possible to control line width.
In case you need to see how it works in Microsoft Project 2013, check this article : How to highlight the Current date line in Gantt chart in Microsoft Project 2013 ?
There is no need of changing it's format. You can just zoom it by simply right clicking the gantt chart space and select "Zoom." That way you can adjust the size of it and view it without any difficulty :)