Ho Optometrist

Your Local Optometrist from 怡保……Ipoh….. Perak, Malaysia

Ocular Disease

According to World Health Organization there are 285 million people are visually impaired worldwide, among them 39 million are blind and 246 have low vision.

About 90% of the world’s visually impaired live in developing countries.

‘ Globally, uncorrected refractive errors are the main cause of visual impairment; cataracts remain the leading cause of blindness in middle- and low-income countries. ‘

The number of people visually impaired from infectious diseases has greatly reduced in the last 20 years. 80% of all visual impairment can be avoided or cured.


There are four levels of visual function, according to the International Classification of Diseases -10 (Update and Revision 2006):

  • Normal Vision
  • Moderate Visual Impairment
  • Severe Visual Impairment
  • Blindness.

Moderate visual impairment combined with severe visual impairment are grouped under the term “low vision”: low vision taken together with blindness represents all visual impairment.

The causes of visual impairment

Globally the major causes of visual impairment are:

  • Uncorrected refractive errors (myopia, hyperopia or astigmatism), 43 %

  • Cataract, 33%

  • Glaucoma, 2%.

 Who is at risk?

Approximately 90% of visually impaired people live in developing countries.

People aged 50 and over

About 65 % of all people who are visually impaired are aged 50 and older, while this age group comprises about 20 % of the world’s population. With an increasing elderly population in many countries, more people will be at risk of age-related visual impairment.

Children below age 15

An estimated 19 million children are visually impaired. Of these, 12 million children are visually impaired due to refractive errors, a condition that could be easily diagnosed and corrected. 1.4 million are irreversibly blind for the rest of their lives.

Changes over the last twenty years

Overall, visual impairment worldwide has decreased since the early 1990s. This is despite an aging global elderly population. This decrease is principally the result of a reduction in visual impairment from infectious diseases through concerted public health action.

The global response to prevention of blindness

Globally, 80% of all visual impairment can be prevented or cured. Areas of progress over the last 20 years include:

  • governments establishing national programmes to prevent and control visual impairment;
  • eye care services increasingly integrated into primary and secondary health care systems, with a focus on the provision of services that are available, affordable and high quality;
  • campaigns to raise awareness, including school-based education; and
  • stronger international partnerships, with engagement of the private sector and civil society.

Data over the last 20 years shows that there has been significant progress in preventing and curing visual impairment in many countries. Furthermore, there has been a massive reduction in onchocerciasis-related blindness as part of a significant reduction in the disease. This has been achieved through a number of successful international partnerships.


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