Developmental Milestones
32 weeks gestation: Retinal vasculature completed. Children born prior to 32 weeks often have Retinopathy of Prematurity.
Birth: Peripheral retina synapse well-formed, accommodation set at 8 to 16 inches, average refractive error +2.00D. Functionally, the child responds to peripheral stimuli (mango-cellular pathway dominant) and fixates parafoveally. The child is interested in circular objects.
1 month: Fovea not developed, visual pathway not myelinized. Functionally, the child’s approximate visual acuity is 20/570 (VER). Acuity, contrast sensitivity, color discrimination, stereopsis become further refined with time as the retina physically matures.
2 months: Dichromat color vision develops, pursuit eye movements developing, head control improved. Functionally, the child develops more interest in black and white targets. Increased tracking of people.
3 months: Bifoveal fixation, myelinization reaches visual cortex (the optic pathways able to transfer information from the optic nerve to the visual cortex) able to make a series of small saccades (tracking eye movement), trichromat color vision, and development of pursuit eye movement skills. Functionally, visual acuity is approximately 20/400-20/200 (VER), color vision develops.
6 months: Cone myelinization/synapse developed, foveal reflex observable, pursuit eye movements developed, binocular vision cells myelinized, improved stereopsis, iris pigmentation develops, and fine motor skills develop. Functionally, visual acuity is approximately 20/20 (VER), right occipital lobe sees objects on the left side and left occipital lobe sees objects on the right side, eye color may change, increased reaching, grasping, and placing objects in mouth.
1 year: Accommodative focusing system more accurate, lacrimal system developed, optic nerve cupping develops, optic nerve head has a pinker appearance, sclera should appear white. Functionally, child sees 20/100 on the Teller Acuity card.
1-1/2-years: Visual spatial skills developing. Functionally, child can throw objects and able to stack 3 blocks.
2 years: Myelinization to the visual cortex complete, cortical function developing (parvo-cellular visual pathway dominant). Functionally, child can see 20/20 on the Teller Acuity card, able to concentrate on central detail, responsive to colors and stationary objects, stereopsis developed, 200 words in vocabulary, runs w/o falling, able to turn pages of book.
2-1/2-years to 3 years: Visual discrimination skills developing.
4-5 years: Visual directionality developing. Functionally, child can begin to distinguish right, left, up, and down.
6 years: Saccades are adult like. Functionally, a child has the saccadic visual skills for pre-reading.
