Visual impairments in children can be caused by a variety of conditions. While some conditions are untreatable, others may be remedied surgically or with the use of corrective lenses. Since much of learning involves vision, it is important to determine what is causing a child's visual impairment and adapt his environment to his abilities in order to give him the best start possible.
Refractive errors occur when an eye has trouble properly bending light to create clear images. Myopia (also known as "nearsightedness") occurs when a child is able to clearly see nearby objects but has trouble seeing objects that are distant. Hyperopia ("farsightedness") is the opposite of myopia. A child with hyperopia has trouble focusing on nearby objects, but distant objects are clearly visible. Finally, a child with astigmatism has trouble clearly seeing both near and far objects. A child with myopia, hyperopia and/or astigmatism can be helped by the use of corrective lenses.
Visual Field Problems
A child that can clearly see objects in front of him may still have problems with his visual field. The visual field is the area within direct range of sight (without the need to turn the head or eyes in order to see something). A child with hemianopsia has problems on one side of his visual field. A child with scotomas may have spots of reduced vision within his field of vision. Some eye conditions may cause a child to have problems with all peripheral (beyond the direct line of sight) vision, creating what is known as tunnel vision. He may also experience the loss of the centre of his field of vision.
Ocular Motor Impairment
Ocular motor impairment occurs when a child has problems with the muscles controlling the eyes. The muscles work with the eyes to allow for fixating on images, following objects, scanning words or seeing in three dimensions. Surgery may help a child with ocular motor problems.
Retinopathy of Prematurity
According to Bright Tots online, retinopathy of prematurity mainly affects premature infants that weigh less than two and three-quarter pounds at birth or infants that have been born prior to 31 weeks of gestation. It occurs when abnormal scar tissue and vessels grow over the retina, typically in both eyes. It can cause lifelong vision problems and blindness.
Cortical Visual Impairment
Cortical visual impairment is not directly related to any conditions of the eye. Actually, it has to do with the brain's visual cortex. A brain with a cortical visual impairment has trouble picking up and understanding visual information being sent to it. The condition is often found in children with cerebral palsy, developmental delays and seizure disorder.
A coloboma is a hole (often a "keyhole" shape) present in one of the eye's structures. It can be found in the lens, iris, retina choroids, eyelid or optic disc. It can be caused when a normal gap ("the choroid fissure") between two eye structures in a foetus does not close entirely before the baby is born. A coloboma can have a number of visual effects that range from mild to severe depending on how large the gap is and where it is found.