One face that has been considered "perfect" is that of the Mona Lisa, or La Jaconde as it is named in the Louvre in France, though, perhaps rather than symmetry, it is the soft play of light and shade upon this half-turned face that fascinates the millions who look upon it.
While no student can recreate this enigmatic face which a master such as Leonardo da Vinci painted, still efforts can be made for symmetry. Drawing an oval for the face (which is considered the "perfect" shape), the student then draws a ever so slightly curved line (very lightly) across this face where the eyes will be. A vertical line comes down from the top of the head to bottom where the nose will be. Measure from this vertical for the placement of the right and left eyes. (You may wish to draw one eye, and then trace this eye on the other side so that the two eyes will be exactly the same and, thus be symmetrical, and almost "perfect.")
(There are a number of diagrams available on the internet by just searching for how to draw a face)
Although the "perfect face" with "perfect eyes" do not exist, there are ways to draw and make realistic. The human face can typically be drawn as an upside egg shape or an oval. Although there are many other shapes of faces that can be found, the oval seems to be the easiest and most common to draw. Draw the face with the top of the head being a bit wider than the bottom, like an upside down egg. To draw the "perfect eyes", you must place them a little below the horizontal middle of the face. No sets of eyes are identical, but the general idea would be that eyes are also shaped like ovals. Only these ovals are on their side. Once your ovals are drawn, you can draw the iris, or the colored part. Then fill in the pupil to make it look black. The outside of the iris needs to be much darker than the inside. After that, take your pencil and draw varying sizes of dark lines coming from the iris to the pupil. Once you have your lines drawn, you can fill in the iris, making sure that your filling is a little bit lighter than the lines you've drawn. To make it more realistic, keep a couple of tiny circles left white to portray reflections of light that can be seen in an eye. Now, draw in the tear ducts at the "pointed" parts of the eye by making curved lines like a stretched out letter "C" on the left sides of the eyes and a backwards "C" on the right sides of the eyes. Fill those in lightly. Go to the top of your eyes and draw and lightly darken in eye lids by drawing a parallel line right above each eye. Then, draw your eyelashes by putting your pencil at the bittom of the eyelid and fan them out with a little bit of curve. You should now have a "perfect" face and set of eyes.