Control the pointer using Dwell
If you enable the Accessibility Keyboard, you can use Dwell, which lets you perform mouse actions using eye- or head-tracking technology. You can easily access dwell actions, such as Left Click, in the Accessibility Keyboard and custom panels or in the menu bar.
After you select a dwell action, you rest, or dwell, for a set amount of time (called the dwell time) on the item that you want to click, drag, or scroll, then the action is performed.
Turn on Dwell
Choose Apple menu > System Preferences, click Accessibility, then click Keyboard.
Click Accessibility Keyboard, then make sure Enable Accessibility Keyboard is selected.
For information about the Accessibility Keyboard options, click the Help button
in the lower right corner of the pane.Click Dwell Options, then select “Show dwell actions in panels,” “Show dwell actions in menu bar,” or both.
Depending on the checkboxes you selected, a row of dwell action buttons appears across the top of the Accessibility Keyboard and custom panels, or a Dwell status menu appears in the menu bar, or both.
Dwell actions
Depending on where you choose to show dwell actions, they’re available in the Accessibility Keyboard and custom panels or the Dwell status menu in the menu bar.
After you select an action, dwell on the spot where you want the action performed—for example, on a checkbox or an image. The dwell pointer 
appears over the item and the dwell time countdown begins (the pointer circle starts to turn white). When the countdown is over, the action is performed.
Note: If you don’t want to see the dwell time countdown on the screen, select “Hide dwell time indicators” in Dwell Options.
Left Click
: Performs a left click when you dwell on an item.Double Click
: Performs a double click when you dwell on an item.Right Click
: Performs a right click when you dwell on an item.Drag & Drop
: Drags and drops the item you dwell on.When the countdown is over, the pointer indicates the item can be dragged. As you dwell where you want to drop the item, the item moves there, the countdown begins, and when it’s over, the item is dropped.
Scroll Menu
: Scrolls the item you dwell on.Make sure you dwell on content that can be scrolled—for example, a webpage or a document. When the countdown is over, scroll indicators appear at the top, bottom, and sides of the content (depending on how it can be scrolled). Dwell on a scroll indicator to scroll in that direction.
Options Menu
: Shows the Options menu when you dwell on an item.When you choose an action from the Options menu, it’s used one time only—the action is not repeated. For more information, see Use the Options menu.
No Action
: Pause and take no action as you move around the screen or dwell on items. This action is useful when you want to take a break from actions—for example, to read a webpage or watch a movie.When you’re ready to resume and perform dwell actions again, dwell on any dwell action in the Accessibility Keyboard. If the Accessibility Keyboard is hidden, dwell on the hot corner assigned to show it (as set in Accessibility Keyboard preferences).
The color of the scroll indicators in the Scroll Menu is determined by the highlight color set in General system preferences. To change the highlight color, choose Apple menu > System Preferences, then click General.
Use the Dwell status menu
If you chose to show dwell actions in the menu bar, you can easily access dwell actions using the Dwell status menu. The icon shown in the menu bar changes as you use different dwell actions.
The Dwell status menu is useful for changing dwell actions when the Accessibility Keyboard or another panel is hidden. A left click to select an action is always performed in the status menu, regardless of the current dwell action.
Open the menu: Dwell on the status menu in the menu bar. The pointer
appears over the status menu and the dwell time countdown begins (the pointer circle starts to turn white). When the countdown is over, the menu opens.Note: If you don’t want to see the dwell time countdown on the screen, select “Hide dwell time indicators” in Dwell Options.
Choose an action from the menu: Dwell on an action. When the countdown is over, the action is selected.
Use the Options menu
You can use the Options menu to quickly switch between various dwell actions. When you select an action from the Options menu, it’s used one time only—the action is not repeated.
Tip: The crosshair in the middle of the Options menu indicates the target location where the action will be performed.
Select an action: In the menu, dwell on the action you want to select—for example, the double-click action. The pointer
appears over the button, and the dwell time countdown begins (the pointer circle starts to turn white). When the countdown is over, the button is selected and the action is performed at the target location.The Options menu disappears from the screen when the action is performed, but reappears as soon as you dwell on another item, so that you can choose another action.
Note: If you don’t want to see the dwell time countdown on the screen, select “Hide dwell time indicators” in Dwell Options.
Close the menu: Dwell on the close button at the bottom of the menu. When the countdown is over, the Options menu closes.
If you’re in a custom panel and want to return to the Accessibility Keyboard or the home panel, click the Home icon 
in the upper right corner of the panel.
You can use the Panel Editor to create custom panels to streamline common tasks and actions for apps. For more information, see Use the Panel Editor.
Tip: You can set an option to have the Accessibility Keyboard or home panel shown when you dwell on a corner of the screen. To set hot corners, choose Apple menu > System Preferences, click Accessibility, click Keyboard, click Accessibility Keyboard, then click Hot Corners.