Visual development with age
||It has been suggested that this article be merged into Visual system. (Discuss) Proposed since September 2014.|
Newborn infants have limited color perception. One study found that 74% of newborns can distinguish red, 36% green, 25% yellow, and 14% blue. After one month performance "improved somewhat." Infant’s eyes don’t have the ability to accommodate. The pediatricians are able to perform non-verbal testing to assess visual acuity of a newborn, detect nearsightedness and astigmatism, and evaluate the eye teaming and alignment. Visual acuity improves from about 20/400 at birth to approximately 20/25 at 6 months of age. All this is happening because the nerve cells in their retina and brain that control vision are not fully developed.
Childhood and Adolescence
Depth perception, focus, tracking and other aspects of vision continue to develop throughout early and middle childhood. From recent studies in the United States and Australia there is some evidence that the amount of time school aged children spend outdoors, in natural light, may have some impact on whether they develop myopia. The condition tends to get somewhat worse through childhood and adolescence, but stabilizes in adulthood. More prominent myopia (nearsightedness) and astigmatism are thought to be inherited. Children with this condition may have to wear glasses.
Eyesight is often one of the first senses affected by aging.
Over time the lens become yellowed and may eventually become brown, a condition known as brunescence or brunescent cataract. Although many factors contribute to yellowing, lifetime exposure to ultraviolet and aging are two main causes.
This is clouding of the lens. Although it may be accompanied by yellowing, clouding and yellowing can occur separately.
The lens becomes inflexible (known as decrease in accommodation) tending to remain fixed at long-distance focus.
This is a kind of blindness that begins at the edge of the field of vision and progresses inward. It may result in tunnel vision. Glaucoma typically involves the outer layers of the optic nerve, sometimes as a result of buildup of fluid and excessive pressure in the eye.
While a healthy adult pupil typically has a size range of 2-8 mm, with age the range gets smaller, trending towards moderately small diameter.
On average tear production declines with age. However, there are a number of age-related conditions that can cause excessive tearing.
- Lane, Kenneth A. (2012). Visual Attention in Children: Theories and Activities. SLACK. p. 7. ISBN 978-1-55642-956-9. Retrieved 4 December 2014.
- Adams, Russell J.; Courage, Mary L.; Mercer, Michele E. (1994). "Systematic measurement of human neonatal color vision". Vision Research 34 (13): 1691–1701. doi:10.1016/0042-6989(94)90127-9. ISSN 0042-6989.
- Harvard Health Publications. The Aging Eye: Preventing and treating eye disease. Harvard Health Publications. p. 20. ISBN 978-1-935555-16-2. Retrieved 15 December 2014.
- Heiting, G.,(2011). Your infant’s vision Development. Retrieved February 27, 2012 from http://www.allaboutvision.com/parents/infants.htm
- The Aging Eye; See into Your future. (2009). Retrieved February 27, 2012 from http://www.realage.com/check-your-health/eye-health/aging-eye