Cataracts- progressive clouding of the lens of one or both eyes. It is a prenatal disorder
Glaucoma- caused by a gradual destruction of the optic nerve because of a build up of pressure caused by poor circulation of the fluids in the eye. It is a prenatal disorder
Retinopathy/ prematurity of retrolental fibroplasia- occurs at birth due to formation of a scar tissue on the retina of one or both eyes. Mainly found in extremely low birth-weight infants. Treatment is available if it is identified early.
Retinal blastoma- type of cancer in the eye. Infants may have eye removed to prevent the spread of cancer throughout the body. Prosthetic eye can be fitted
Physical problems within the brain- infection before, during, or after birth can damage optic nerve or visual cortex (portion of brain responsible for processing messages from the eyes), eyes appear normal
Cortical/Cerebral Visual Impairment - vision loss due to damage of parts of brain responsible for receiving and interpreting visual information from the eyes. Often accompanied with other developmental disabilities (Allen, Paasch, Langford & Nolan, 2011).
Visual Acuity
Astigmatism- defect in the lens caused by uneven refraction in different planes causing blurred vision
Hyperopia (farsightedness)- objects that are close up appear less clear
Myopia (nearsightedness)- far away objects appear less clear (Allen et al., 2011).
Muscular Imbalances
Amblyopia (lazy eye)- causes double vision and for children brain may repress the image from the eye and eventually destroy the eyes ability to function altogether. Often there are no signs and alignment of the eye appears normal.
Strabismus- two eyes are unable to focus together. Several forms including cross eyed, wandering eye, wall-eyed (one eye that turns in or outward). Brain generally shuts off the non-dominant eye to avoid seeing double which causes further implications because the eye will not develop if it is not in use leading to permanent loss of vision in that eye if not corrected
Nystagmus- characterized by quick, involuntary, jerky eye movements which interfere with ability to see. Usually are caused by neurological abnormalities and not by problems with eye muscles. This condition can improve with age (Allen et al., 2011)