Depth Perception: Retinal Disparity vs Stereopsis

July 31, 2023


Depth perception is essential to the way we view the world. It’s a complex process that relies on retinal disparity to achieve depth perception, also known as stereopsis.

Do you want to learn more about retinal disparity and stereopsis?

The experts at OOMC have put together this page to help patients understand what’s happening inside their eyes. If you suspect you may need an exam to measure your depth perception, contact OOMC to schedule an appointment!

What Is Retinal Disparity?

Eye on screen displayRetinal disparity, or binocular disparity, is the difference between what you see through each eye. Due to the fact that your eyes are in two different locations on your face, the viewing angle is slightly different for each eye.

You can experience retinal disparity for yourself. Close one eye and hold a finger at an arm’s length away. Open the other eye and close the first eye. Do you see how the finger seems to move? That’s retinal disparity!

This slight image difference between the two eyes (retinal disparity) helps generate depth (stereopsis) when viewing an object. The brain combines these two slightly different images from both eyes to create a 3D perception of the world.

What Is Stereopsis?

Stereopsis is our ability to sense depth and 3-dimensionality. It’s largely a result of the unification of the slightly different images we get from our two eyes. This helps us navigate and properly react to the world around us.

Common everyday things we do with the help of stereopsis include driving and playing sports.

Types of Stereopsis

There are two types of stereopsis: course and fine stereopsis.

Course stereopsis, sometimes called gross stereopsis, uses retinal disparity cues to understand large and easy-to-see amounts of depth. Course stereopsis helps you navigate the world and understand your position in a space.

Fine stereopsis helps determine the smaller amounts of depth between objects. This is often needed for performing fine-motor tasks, such as threading a needle. Fine stereopsis can be measured during eye exams.

Testing Stereopsis

Color Eye dot testThere are several methods for testing someone’s stereopsis, including:

  • Random dot tests
  • Contour tests

Random dot tests ask the patient to find a shape or pattern within a collection of scattered dots.

Contour tests require a patient to combine several images to find a shape or pattern within them.

Both tests often require some form of dissociation for the patient, such as wearing polarized lenses with red/green or red/blue lenses to distort color.

Schedule an Appointment To Test Your Depth Perception

If you suspect your eyes, or your child’s eyes, may be struggling with depth perception, an OOMC practice can help.

Our pediatric and adult ophthalmologists can test depth perception and create a treatment plan. We’ll work with your current eye doctor to ensure your care is personal and addresses your specific needs.

Contact your local OOMC practice to schedule an appointment today.

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