Generated by SassMeister.com.

SassMeister-input-HTML.html

<div class="eye"></div>

SassMeister-input.scss

// ----
// Sass (v3.3.7)
// Compass (v1.0.0.alpha.18)
// ----

@import "compass";
.eye{
  position: relative;
  width: 400px;
  height: 200px;
  margin: 0 auto;
  &:before{
    @include border-radius(40px);
    border: 1px solid #636363;
    width: 40px;
    height: 40px;
    position: absolute;
    content: '';
    top: 50%;
    left: 50%;
  }
}

SassMeister-output.css

.eye {
  position: relative;
  width: 400px;
  height: 200px;
  margin: 0 auto;
  background: #000;
}
.eye:before {
  -moz-border-radius: 40px;
  -webkit-border-radius: 40px;
  border-radius: 40px;
  border: 1px solid #636363;
  width: 40px;
  height: 40px;
  position: absolute;
  content: '';
  top: 50%;
  left: 50%;
}

SassMeister-rendered.html

<div class="eye"></div>