Babies are cute with their small bodies and big eyes. When we’re born, our eyes are about two-thirds smaller than they’ll be when we reach adulthood.

Our eyes grow over our lifetime, especially during the first two years of our life and during puberty when we’re teenagers. For the rest of our lives, our eyes continue to undergo different changes.

Babies are born with eyes about 16.5 millimeters in length. People’s eyes stop growing in length by the age of 20 or 21, when they reach about 24 millimeters.

The weight of the eyes’ lenses continues to increase over time. Scientists say that eyes grow rapidly after birth. Then, within a few months, the growth becomes linear and the lenses grow at a weight of 1.38 milligrams per year over the course of a lifetime.

Eyes stop growing in length when a person reaches around 20 to 21 years of age. However, the weight continues to increase throughout a person’s lifetime.

Turns out, our eyes aren’t only smaller when we’re born, they’re also less useful. We develop our ability to move, focus, and use our eyes over time.

When a human embryo begins to form, it doesn’t have eyes. The major development of the eyes occurs between weeks 3 and 10. By a fetus’ third week, the brain starts developing the eyes’ inner workings of being able to see and process images.

It’s common for babies’ eyes to develop unevenly and is rarely a cause for concern. Vision is the last sense a fetus develops and its eyelids remain closed until 28 weeks. After 28 weeks, a fetus can sense sunlight.

After birth, a baby experiences the world through their eyes mostly as a blur of visual stimuli. Some babies’ eye color starts to change in their first months of life, as many are born with gray or blue eyes that change color.

Babies are nearsighted and focus primarily on objects between 8 and 10 inches from their face. That’s about the distance of a baby’s face to a person who may be holding them.

During the first few months of life, their eyes begin to start working together as hand-eye coordination develops. By 8 weeks, babies can more easily focus on the faces of those around them. By 3 months, babies should begin to start following moving objects and people with their eyes.

By 5 months, a baby has developed color vision and some depth perception. Between 1 and 2 years of age, a child’s hand-eye coordination and depth perception are more developed. Colors and images appear bright and vivid. Most people have a blind spot in their eyes and that’s completely normal.

The eyes continue to grow and undergo an extra growth spurt during puberty. A person’s eyes will reach their adult size by the time they reach age 19. By then, most people display signs of any eye abnormality, and genetic diseases and disorders of the eyes. Some common conditions include:

Our eyes continue to change as we age, especially after age 40. Around this time, our eyes start to lose their ability to focus. This condition is referred to as presbyopia, and some people experience a greater loss of focus than others.

As we age, eyes also tend to dry out and tear excessively. Many age-related eye conditions can be corrected with use of glasses and contact lenses.

Over time, the risk for developing eye and vision problems continues to increase. This is especially true if you have chronic health issues or medical conditions, a family history of eye disease, or an occupation that’s visually demanding or can damage your eyes. You may be experiencing vision issues if:

  • your vision changes or is inconsistent
  • you experience an increased number of floaters or flashes in the eyes
  • you have a loss of vision or notice your sight forms distorted images

After age 60, many experience deteriorating eye health and vision issues, such as:

Taking good care of your eyes and maintaining a healthy diet and exercise regimen can help ensure your eyes work well for as long as possible, and may even improve your eyesight.

While babies’ eyes are developed at birth, it takes up to 2 years for eyesight to fully develop. Eyes grow rapidly after birth and again during puberty until age 20 or 21, when they stop growing in size.

Eyes continue to increase in weight and undergo age-related changes. Staying healthy and taking care of the eyes can help minimize age-related conditions affecting eyesight.