About blindness
Generally speaking, only a very small proportion of people are totally blind. According to the census conducted by the government of Hong Kong Special Administrative Region in 2009, approximately 122,600 Hong Kong citizens have seeing difficulties, taking up1.8% of the total population. Among these people, 11,000 are totally blind, of whom 60% are over 60 years old.
Most people with seeing difficulty have different degrees of vision, for example, they may:
- have light perception
- be able to recognize hand movement
- be able to recognize colour shade
Blind or not, all people with seeing difficulty are generally referred to as “visually impaired”.
Classes of Visual Impairment: :Low Vision and Blindness
The following is the respective definition of low vision and blindness given by the World Health Organisation.
Low Vision:
After treatment and correction, the eye with better vision is below 0.33(1/3), but of or above 0.05(1/20). The population of people with low vision is 4 times that of blind people.
Total Blindness/Loss of Sight:
After treatment and correction, the eye with better vision is below 0.05 (1/20), or the central vision is good, but the visual field is less than 10 degrees.
The blind include both the totally blind and those with some residual vision.
Distinctive Features of People with Low Vision
People with low vision cannot get normal vision when wearing glasses/contact lenses or after operation/medication.
People with low vision are not totally blind but have different degrees of vision.
