Blindness localisation, global strategies Topic 65&66
= inability to perceive light and is usually measured according to Visual acuity test
There are grades to visual impairment the last three grades determine the extent of blindness
Grade 3 visual impairment (blindness)→ 3/60 – 1/60
Grade 4 → less than 1/60 visual field less than 5 degrees
Grade 5 → no light perception
There exists the idea of Avoidable blindness (curable and preventable)
Curable → cataract blindness by surgery or trachoma
Preventable→ corneal blindness due to Vitamin A deficiency
180 Million people are visually disabled 45 million= blind
80 % is avoidable, 32% within 45-59 years of age; 58% above 60
Big link between developing countries and blindness 90 % in developing
60 % of them in Sub-Saharan Africa, China and India
Causes of global blindness
Cataract= 19 million, glaucoma= 6.4 million, Trachoma= 5.6 million, childhood= 1.5 million
Onchocerciasis (parasitic worm Onchocerca volvulus) 0.3 million Others 10 million
In developed, 50 % Age related macular degeneration, 10-20 % glaucoma, then diabetes and cataract
In developing frequent cases are cataract, infection diseases, xerophthalmia (dry eyes, vitamin A deficiency), injuries, glaucoma and Onchocerciasis
Primary location: Retina (macular degeneration, glaucoma and diabetes ), lens cataract, but also cornea and even scleritis or optic neuritis
Global fight against blindness
The WHO in conjunction with IAPB ( international agency for the prevention of blindness) have developed the vision 2020 program called ‘’the right to see’’
General strategies:
Assess common blinding disorder, locally, regionally and nationally
Establish national level progress for control for blindness
Train eye care providers and research into appropriate technology to be used during operation management
Objective:
Elimination of avoidable blindness by 2020
5 diseases were chosen as priority to tackle because of the amount they are causing and feasibility and affordability of control and treatment
- Cataract
- Largest cause with 19 million and the aim is to increase catractic surgery rate
- Childhood blindness
- priority because of the amount of years you have to live with the condition
- 0.5-1/1000 of 0-15 year old
- Each year 500 000 children become blind
- Causes: vitamin A deficiency, measles, conjunctivitis, ophthalmia neonatorum ( Neisseria or gonorrhoea) ,congenital cataract & retinopathy of prematurity (abnormal blood vessel development
- Strategies: immunisation against measles, Vitamin A supplements, O2 monitoring of premature, promote screening and management of diseases in schools ,remote areas and surgical management
- Trachoma blindness
- Leading cause of preventable disease with 5.9 million