What is a visual impairment:
A visual impairment is when a person’s vison cannot be corrected to a “normal” level through intervention such as glasses, contact lenses, medication, vision surgery or visual perception optometrist exercises. It is where one or more function of the eye, or visual system is impaired or limited.
A visual impairment can range from a mild vision impairment to total blindness.
Types of visual impairment
- Central vision loss
- The central part of an individual’s vision is impaired. They may be able to see in their peripheral vision; however, they are unable to see directly in front of them where their eyes are fixed, making reading, writing, and face recognition very difficult.
- Peripheral vision loss
- Impaired peripheral vision is also known as “tunnel vision,” where an individual’s visual field narrows. They can see right in front of them where their eyes are fixed, but they are limited in navigating their environment and may need to turn their head to gain visual input. An individual with peripheral vision loss may have difficulties following a moving object with their eyes.
- Blurry vision
- Blurry vision can be described as looking through frosted glass. Someone with blurry vison can have difficulty identifying objects, will only perceive vague shapes, and find depth of perception and changes in surfaces challenging. Their vison can become further limited in bright environments.
- Visual disorders following brain injuries:
- Visual impairment caused by trauma or brain injury is varied, usually it is not the visual function that is impaired, but the ability of the brain to analyse visual information. In other cases, visual impairments as a result of brain injuries can be due to damage to the visual cortex (occipital lobe).
Most common causes of visual impairments
- Neurological conditions that affect the parts of the brain that control vison.
- Retinopathy of Prematurity (ROP)
- Optic Nerve Hypoplasia (ONH)
- Damage or injury to the eye or neuropathways such as Optic Nerve Atrophy (ONA).
- Genetic conditions such as albinism and retinitis pigmentosa
- Cancers like retinoblastoma
- Paediatric glaucoma or cataracts
- Microphthalmia or Anophthalmia
When is a child considered legally blind:
- They cannot see at 6 m what a child with “normal” vision can see at 60 meters.
- Their field of vision is less than 20° in diameter (a person with “normal” vision can see 180°).
Role of OT in supporting children with vison impairments:
Tactile discrimination – for those individuals with a visual impairment, being able to tactually explore an object can provide the additional information needed to confirm an impression gained visually or identify an object.
Auditory discrimination – For safety, particularly when out in the community, through identifying where noises are coming from, how close or far away noises are, such as traffic, in order to maintain safety.
Depth of perception – Develop a child’s ability to identify an object’s size and how far away it is from them. When possible, this is developed in order to enable a child to safely explore their environment and engage in a wider range of meaningful activities.
Compensatory strategies (familiarising with environment) – Recalling where furniture is in order to navigate their environment safely, as well as frequently used items, to enable increased independence with daily activities.
Adapting environment – Occupational Therapists can review a child’s home and school environment and make recommendations to enable increased participation and safety. This can include major or minor assistive technology or home modifications such as:
- Coloured reflective lines on change of surface and levels
- Limiting glare
- Limiting visual clutter
- Changing font sizing
- Slope boards
Self-advocacy – Supporting a child to develop their ability to self-advocate for their needs, such as asking for help when needed or for others to make the necessary adjustments to enable them to participate.
Other services to be involved:
Orthoptist – Support with offering information about a child’s level of vision and how to optimise vision for daily activities. They can offer environment assessments and visual aids.
Guide Dogs NSW/ACT – Offer orientation and mobility recommendations.
Ophthalmologist – Support with diagnosis and management of visual impairments.
Physiotherapist – to develop confidence with walking across different surfaces and levels, climbing, coordination and balance.