An important element of the portrait is the accent of the eyes. There are times when basic photo adjustments can make a huge difference. Photoshop allows you to make your eyes more expressive and vivid. If you don't want to use the Operation tool, you can also use the Sharpen or Dodge / Burn tool to make eye editing easier in any version of Photoshop.
Steps
Method 1 of 2: using the Sharpen tool

Step 1. Enlarge the image
Use the magnification tools to focus on one eye first. This will make it easier to complete the task and see your changes in detail.

Step 2. Select the eye with the magnetic lasso
The Magnetic Lasso is a selection tool to draw out the rough outline of a shape. This will allow you to select an area with the smoothest and most even edge possible. This procedure will be much easier than using a regular lasso, because you don't have to draw perfect lines to highlight the eye area. Click on the magnetic lasso on the side panel and then carefully outline the shape of the iris (only the colored part).

Step 3. Select "Pen"
This tool allows you to blend the edited and unedited areas of the image so that any changes made to small areas are not too harsh. You can find the feather in the layer tab, at the top of the menu bar. Change the value in the "Pen" field to "10" - you can experiment with the value to choose the position you like.

Step 4. Select "Blur the path"
In the top menu bar, select the Filter tab, scroll down to the Blur Path tool. This tool, although it sounds like the opposite, allows you to sharpen the aperture and work out the details as well as the color of the image. After clicking on the button, you will have the opportunity to change the circuit settings. Change the "radius" to 3.6 and "start" to 0. Experiment with the values to find what you like.
Remember that decreasing the value will increase the sharpness. Too high a sharpness can displace realism from the picture

Step 5. Adjust the contrast
The last thing you can do to finish the project is to adjust the contrast. Select the contrast tool from the photo editing tab on the top menu bar and move the slider (change the value) to change the contrast. Small changes to the values have a big impact, so be careful not to overdo it.

Step 6. Repeat with the other eye, try to use the same values as for the first eye
When you think the project is ready, scale down the image to make sure it looks better overall and doesn't look cartoonish.

Step 7. Done
Method 2 of 2: using the Burn and Burn tools

Step 1. Duplicate the background layer
This will help insure you against mistakes in the original background. Select the background layer, then click the "layer menu" button and click the "duplicate layer" button. Rename the layer in the dialog that appears, or just click OK and the duplicate layer will be marked as a copy of the background. To easily recognize the working layer, rename it something like "Eyes".

Step 2. Enlarge the eyes
Use the zoom tool to zoom in on one eye.

Step 3. Select the Burn tool from the toolbar on the right
This tool will help to select the eyes, but will brighten the selection a little.

Step 4. Set the parameters of the Burn tool
Before using this tool, you need to change the settings in the small dialog box that appears at the top. You will want to select a brush to paint over only the diaphragm (the colored part of the eye). Adjust the brush thickness to 10%, range to midtones, and exposure to 20%.

Step 5. Use the Burn tool on the eye
Slowly process the outline of the eye by clicking on parts of the iris with your cursor to use the Burn tool. Avoid gaps (black parts that expand or contract depending on the lighting). Note that this tool brightens the eyes.

Step 6. Select the Dodge tool
This tool allows you to subtly darken the edges of an object. Right click on the Burn tool in the toolbar. A window will open showing more than three options. This time, select Dodge. The icon symbol changes to a hand.

Step 7. Adjust the parameters of the Dodge tool
Change the size of the brush. Again, the size of the brush will depend on the size of the eye. Set the brush thickness to 10%, range for darkening and exposure to 15%.

Step 8. Use Dodge on the edge of the iris
Press on the perimeter of the pupil and iris until they darken slightly to enhance their appearance. The brush will make the adjustments you set automatically.

Step 9. Complete your project
Repeat the above steps on the other eye to make them the same. Take some time to reduce the size of the image and make sure that the changes you make are not conspicuous.