Inclusive Airport Navigation – Appendix 3: Visual Impairments

The most common visual impairments and their symptoms or effects include: 1 [1.]

• Astigmatism – Distorted or blurred representation of objects at any distance caused by an imbalance in the cornea curve. Usually correctable by glasses or contact lenses.
• Cataracts – Blurred vision similar to the view through a steamed window. Results from the clouding of the lens of the eye. Cataracts can be age related, a birth defect or caused by an injury. Night vision decreases, colours might appear more pale, bright lights can cause an overpowering effect and sometimes even double vision might occur. Cataracts can be treated by surgically removing the clouds formed within the eye.
• Colour-Blindness – “{…} having an inability to see the difference between some or, very rarely, all colors.” [2.] It is inherited and occurs in approximately 10%-12% of male European descents. Most commonly colour-blindness results in difficulties at distinguishing between some or all red and some or all green tones.
• Floaters – Very common, almost 50% for people over the age of 50. As the vitreous shrinks it often separates form the retina producing small clumps interpreted as shadows. In time the brain learns to ignore these sometimes very irritating shapes that mostly occur against light backgrounds.
• Flashing Lights – Also caused by the shrinking vitreous, flashing lights might develop concomitant with floaters. They are short bright flashes of yellow or white light often occurring in the peripheral vision or dark.
• Glaucoma – Loss of peripheral vision caused by damaged nerves at the back of the eye. Very common phenomenon, effecting 1 out of 50 people over 40 in the UK alone. Age, myopia, stroke and early heart attack might be risk factors amongst others.
• Hyperopia and Myopia – Most commonly referred to as long-sightedness (hyperopia) and short-sightedness (myopia) and correctable with glasses or contact lenses. Caused by the wrong relation between the cornea and the lens of the eye resulting in blurred vision for different distances.
• Macular Degeneration – The macula – the central area of the retina – is responsible for detail, acuity and central vision. Resulting in the progressive loss of central vision and blindness, the macula degenerates over time. Usually peripheral vision stays almost intact leaving the person affected with black spots or ‘holes’ in the centre of their vision.
• Presbyopia – Difficulty at focussing caused by decreased flexibility of the eye. Often occurring after the age of 40. Correctible with glasses or contact lenses.