By what age is binocularity typically achieved in infants?

• A. By 1 month
• B. By 3 to 4 months
• C. By 6 to 8 months
• D. By 12 months

Answer: (B)

Binocular vision arises as the eyes learn to align and the brain learns to fuse input from both eyes. This typically develops by about three to four months, when the extraocular muscles coordinate and neural pathways mature enough for two-eyed fusion. At this age, you’d expect the infant to fix on and track objects with both eyes working together, rather than one eye drifting or working in isolation. If binocularity isn’t evident by this time, it may indicate a vision problem such as strabismus and should be evaluated promptly. By six to eight months, binocular function is usually established, with depth perception beginning to emerge.