Parents often wonder how well their new baby sees. Visual acuity -- the ability to see clearly and sharply -- depends on the development of the macula, the structure in the retina that allows for clear, sharp vision. At birth, the macula is the least developed structure of the eye, according to pediatric ophthalmologist Dr. Kenneth Wright, and full maturation of the macula takes around four years.
The Purpose of the Macula
The macula is the focal point for vision on the retina, the inner layer of the eye. The macula contains photoreceptors, including rods and cones, which allow your baby to see clearly as well as in color and in darkness. Cones are responsible for clear vision, as well as for the ability to see color, while rods allow you to see in the dark and in low light. The central point of the macula, the fovea, contains mostly rods at birth; over a few months, the rods migrate outward and the fovea becomes packed with cones.
A newborn doesn't see well for many reasons; the lack of cones in the macula is just one. His pupil is also constricted, because his eye is highly sensitive to light, which allows less light into the retina. His pupil will begin to enlarge around age 2 weeks. He can't focus well, because his eyes don't yet work as a matched set. The ability to use both eyes together to focus an image on the macula develops around age 2 months, according to the Smith-Kettlewell Eye Research Institute.
At birth, your baby sees in shades of black and white, rather than in color, because the fovea contains few cones. By 2 to 3 months, your baby starts to see colors as cones accumulate in the fovea. The first color your baby can see is red, according to a December 2008 article published in "Newborn and Infant Nursing Reviews." By around 4 months of age, your baby can see a full spectrum of colors well, says the American Academy of Ophthalmology.
Changes in Visual Acuity
The cones in the macula are responsible for visual acuity. As cone density increases and rods migrate to the periphery of the macula over the first 4 years of life, so does sharp, clear vision. At birth, your baby has a visual acuity of 20/120; in other words, he sees from 20 feet away what most people can see from 120 feet. It's the equivalent of being able to see the big "E" on the eye chart. At 4 months, his vision improves to 20/60. By age 8 months, his vision has improved to nearly adult levels; his visual acuity is now 20/30. By age 8, all children with normal eye development should have 20/20 vision, family practice physician Dr. Peter Broderick explains in a 1998 "American Family Physician" article.