Can we reduce cursor height same as font-height if we specify line-height greater than font-size. Have a look at this fiddle in Chrome browser and you will get what I am talking
try this for line height space between line...
<div style="background-color: lime; line-height: 2cm;">
testing line height - line 1 <br>
testing line height - line 2 <br>
</div>
It sounds as if you want to change the Caret located inside the text area. Here's a post that covers this.
Styling text input caret
I have tried this code in Chrome and it was successful. Now you implement and check your code.
<TEXTAREA style="font-family: Arial, Helvetica, sans-serif; font-size:13px; line-height: 10px; height: 150px;"></TEXTAREA>