From the Guidelines
Stereoscopic vision is crucial for accurately judging distances, navigating environments, and performing precise tasks, and its development during early childhood is essential for normal depth perception later in life. This process occurs because our eyes are positioned approximately 6-7 cm apart, causing each eye to capture a slightly different perspective of the same scene. The brain then combines these two slightly different images through a process called binocular fusion, creating a single three-dimensional perception. Stereoscopic vision relies on several visual cues, including binocular disparity (the difference between the two retinal images), convergence (how much the eyes turn inward when focusing on close objects), and accommodation (the focusing of the lens) 1.
Importance of Stereoscopic Vision
Animals with forward-facing eyes, like humans and predators, typically have good stereoscopic vision, which helps with hunting or precise movement. Those with eyes on the sides of their heads, like many prey animals, sacrifice some depth perception for a wider field of view to detect predators. According to a study published in Ophthalmology, timely treatment of amblyopia, which can affect stereoscopic vision, usually improves visual acuity, may improve binocularity, and decreases the likelihood of a visual handicap if there is loss of vision in the fellow eye later in life 1.
Development and Assessment
Stereoscopic vision develops during early childhood, and proper visual development in both eyes during this critical period is essential for normal depth perception later in life. The American Academy of Pediatrics recommends vision screening at all well-child visits for children starting in the newborn period to 3 years, including ocular history, vision assessment, external inspection of the eyes and lids, ocular motility assessment, pupil examination, and red reflex examination 1. For children aged 3 to 5 years, the AAP recommends the aforementioned screening in addition to age-appropriate visual acuity measurement and ophthalmoscopy.
Treatment and Outcomes
Early detection and treatment of amblyopia and amblyogenic risk factors can improve visual acuity, and treatments include surgery for strabismus and cataracts, use of glasses, contact lenses, or refractive surgery treatments to correct refractive error, and visual training, patching, or atropine therapy of the nonamblyopic eye to treat amblyopia 1. A study published in Ophthalmology found that maintenance of good vision in each eye with appropriate amblyopia treatment is an important part of successful management of strabismus, and all children with amblyopia should be offered treatment regardless of age 1. Treatment of strabismus can also promote binocular vision and improve visual function in each eye, and may be useful in sports such as baseball and activities such as needlepoint and watching 3D movies 1.
From the Research
Stereoscopic Vision Overview
- Stereoscopic vision is the ability to perceive three-dimensional (3D) images from two-dimensional (2D) images formed on the retinas [(2,3,4)].
- This is made possible by the horizontal separation of the two eyes, which gives rise to small positional differences, called binocular disparities, between corresponding features in the two retinal images 4.
Key Factors in Stereoscopic Vision
- Depth cue interactions in stereo 3D media play a crucial role in creating a faithful impression of the 3D structure of the scene being portrayed 2.
- Focusing and fixating on stereo images are also important factors to consider in the creation and presentation of stereo 3D imagery 2.
- Temporal presentation protocols can affect flicker, motion artifacts, and depth distortion in stereoscopic vision 2.
Neurophysiology of Stereopsis
- The brain extracts and processes binocular disparities to create a rich 3D representation of our visual surroundings 4.
- Neurons selective for binocular disparity have been found in several visual areas, but the brain circuits that give rise to stereoscopic vision are not very well understood 4.
Applications of Stereoscopic Vision
- Stereoscopic displays have become important for many applications, including operation of remote devices, medical imaging, surgery, scientific visualization, and computer-assisted design 2.
- The incorporation of stereo technology into entertainment, such as cinema, television, and video games, has also become significant 2.