Course: Visual Assessment of Children: The Orthoptist Role

Presented on Wednesday 9 February 2005

Multidisciplinary Functional Vision Assessment

Gillian Coyle, Senior Orthoptist

Functional vision

The ability to use sight in everyday situations

It allows:

• Access to information
• Social interaction
• Mobility

Functional Vision Assessment Team

• Community Paediatrician
• Orthoptist
• Specialist Teacher for Visually Impaired Children
• Optometrist

Aims

• To describe the vision available in daily activities
• To identify the visual difficulties
• To develop strategies to help overcome the difficulties
• To maximise the use of residual vision.
• To enable the child to reach their development and educational potential

How is vision measured?

Traditional

Reduced Visual Acuity 6/18

Resudec visual acuity 6/60

Limitations - optimum conditions

• Lighting
• Maximum contrast
• Important but incomplete assessment of vision

How is vision measured?

Other parameters

The Assessment

• CDC or school
• Assessment
  developmental age
  severity of visual impairment
  associated difficulties

History

• Paediatric
• Ophthalmic
• Visual
  recognition, orientation, crowding, depth perception, visual memory, perception of movement, visual fatigue
  Dutton et al, Developmental Medicine and Child Neurology 1999, 41: 298-306

Observed Visual Behaviour

Detection Vision

Visual Acuity Tests

Visual Field Testing

Visual field defects

• peripheral looss - tunnel vision
• hemianopia

Contrast sensitivity test

• Normal/reduced contrast



• Normal/defective colour vision



• Cone adaptation test - night blindness

Eye movements

• Maintain fixation on an object
• Follow moving object
• Look from one object to another
• Use the eyes together
• Observation of speed

Testing eye movements

Recognition of people

Visual Assessment of Children: The Orthoptist Role