Visual impairment or loss of sight is the partial or total impairment of vision. Many people develop some type of visual problem at some point in their lives. Some can no longer see distant objects, others have trouble reading small letters, but these conditions are easily treated. Visual impairment occurs when one or more parts of the eye or the brain that are needed to process images are damaged. In these cases, vision cannot be fully restored with conventional medical treatments, such as glasses, corrective lenses, or even surgery.

Causes of Visual Impairment?

Visual impairment rarely affects vision during adolescence. When it does, it is usually due to eye damage or failures in the brain that cannot receive the visual signals sent by the eyes. Underlying diseases can also cause visual impairment. The most common cause is diabetic retinopathy, age-related macular degeneration, cataract formation, and high eye pressure leading to glaucoma. Some babies have congenital blindness, which means they have visual impairment from birth. Congenital blindness can be caused by several factors – it can be inherited, for example, or caused by an infection (such as measles) that is passed from the mother to the developing baby during pregnancy. Conditions that can cause vision loss include:

Amblyopia

This is reduced vision in one eye caused by lack of use of that eye in early childhood. Some conditions cause a child’s eyes to send different messages to the brain (for example, one eye may focus better than the other). The brain may then shut off or suppress images from the weaker eye and the vision in that eye then stops developing normally. This is also known as “lazy eye.” Strabismus (misaligned or crossed eyes) is a common cause of amblyopia, as the brain begins to ignore messages sent by the misaligned eye.

Cataract

This refers to partial or total clouding of the lens. The lens is a natural part of the eye located behind the pupil. It helps focus light rays to form an image on the retina, so any alteration in its structure affects clear vision. Cataracts prevent light from passing through the lens easily and this causes vision loss. They usually develop slowly and generally affect people in their 60s and 70s, but sometimes babies are born with congenital cataracts.

Diabetic Retinopathy

Occurs when the small blood vessels in the retina are damaged due to diabetes. People with retinopathy may not have vision problems at first. But if the condition worsens, they can become blind. Teenagers with diabetes should make sure to have regular eye exams because there are no early warning signs for this condition.

Glaucoma

This is an increase in the pressure inside the eye. Increased pressure damages vision by damaging the optic nerve. Glaucoma is seen mainly in older adults, although babies can be born with the condition and children and teenagers may sometimes develop it as well.

Macular Degeneration

This is a progressive deterioration of the macula, the most sensitive area of the retina. The condition leads to gradual loss of central vision (the ability to see fine details directly in front). Macular degeneration is often age-related (it occurs in older people, especially those over 60), but sometimes can occur in younger people as well. Excessive exposure to sunlight and smoking can increase the risk of age-related macular degeneration. Symptoms may include increasing difficulty reading or watching television, or distorted vision in which straight lines appear wavy or objects seem larger or smaller than normal.

Trachoma

This occurs when a highly contagious microorganism called Chlamydia trachomatis causes inflammation in the eye. It is often found in rural environments or places with limited access to water and sanitation.

How Is Visual Impairment Diagnosed?

Detection of visual impairment is done by the ophthalmologist, who will examine the structure of the eyes. Other simple tests that may be performed to diagnose visual impairment include:

  • Visual acuity test – Reading lines of letters that decrease in size and are displayed at a standardized distance from the person being tested.
  • Visual field test – Accurately assesses failures in the patient’s central and peripheral visual field, detecting areas without vision that may be caused by various diseases.
  • Tonometer test – This test determines the pressure of the fluid inside the eye to evaluate for glaucoma.

Treatment

If the doctor determines that there is a condition in the eye that may lead to the development of visual impairment, some treatments are available. Options may include glasses, contact lenses, eye drops or other medications. In some cases, surgery may be necessary. Cataracts, for example, are often treated with removal of the cloudy lens and its replacement with an intraocular lens (made of artificial plastic that requires no special care and thus restores vision). Other methods can compensate for vision loss. Guide dogs can help people move from place to place independently. Braille allows people with visual impairment to read and write. Special equipment such as computers, microscopic and telescopic glasses, and voice recognition software make school and homework easier.

Visual Impairment at School

Visual impairment interferes with the functioning of a regular school program, or, for preschool children, with learning tasks. Federal Law No. 7,853/99 officially defines the condition as follows: “a vision impairment which, even with correction, negatively affects the child’s educational performance.” Although the causes vary, there are several common signs that may indicate a child has a visual impairment. These include:

  • Irregular eye movements (for example, eyes that do not move together or appear unfocused)
  • Unusual habits (such as covering one eye or frequently rubbing the eyes)
  • Sitting very close to the television or holding a book very close to the face
  • Not copying activities from the board, or copying them illegibly

Educational Challenges

A child with visual impairment benefits from Decree 6,571, of September 17, 2008, which states that “the State has the duty to provide technical and financial support so that specialized services are present throughout the public education network.” But it is up to the school administration and the Departments of Education to manage and request resources for this purpose. Intelligence does not depend on sight; therefore, overcoming educational challenges is essential to enable a student with visual impairment to reach their full academic potential. These challenges may include:

  • Moving safely within the classroom
  • Reading in Braille (Braille literacy for children with total blindness or severe visual impairment occurs at the same time as normal literacy)
  • Using educational tools such as calculators and voice-enabled word processing software

Tips for Schools

A child with visual impairment requires school inclusion, but for them to succeed, it is important to provide adapted environments, tactile flooring, unobstructed corridors, Braille signage, and stairs with color contrasts on the steps. The school environment should also be accessible, with the installation of audible signals at traffic lights and in areas near the school’s vehicle exits. These are important measures that respect the condition of people with visual impairment. See Also: Braille – Words at Your Fingertips Photos: visualpun.ch