Blindness
The two main causes of blindness, cataracts and trachoma, are both curable with reasonably cheap surgery. Several charities provide this at moderately cost-effective rates, but none are as cost-effective as drug-based treatments for other diseases.
The two main types of easily curable blindness are cataracts and trachoma.
Cataracts
A cataract is clouding of the lens of the eye, which impedes the passage of light. Most cataracts are related to ageing, although occasionally children may be born with the condition, or cataract may develop after an injury, inflammation or disease. Vision can be restored by surgically removing the affected lens, and replacing it by an artificial one.1
Reference:
| 1. |
Trachoma
Trachoma is a bacterial infection. It spreads from person to person, and is frequently passed from child to child and from child to mother, especially where there are shortages of water, numerous flies, and crowded living conditions.
Infection often begins during infancy or childhood and can become chronic. If left untreated, the infection eventually causes the eyelid to turn inwards, which in turn causes the eyelashes to rub on the eyeball, resulting in intense pain and scarring of the front of the eye. This ultimately leads to irreversible blindness, typically between 30 and 40 years of age.2
Reference:
| 2. |
Cost-Effectiveness
For each of these conditions, there is a fairly simple surgical operation.
Charities which focus on blindness often advertise their cost-effectiveness in terms of the amount of money one sight-saving surgery costs (note that one surgery is the fixing of one eye, so someone who is blind will require two surgeries):
| Organization | Advertized cost per surgery |
|---|---|
| Fred Hollows Foundation | $15 |
| Sightsavers International | $26 |
| Orbis | $33 |
| Unite for Sight | $50 |
In contrast, the DCP2 and WHO-CHOICE cost-effectiveness estimates are as follows:
In other words, according to the WHO-CHOICE report, it would cost $10 to completely restore, by targeted trachoma surgery, the sight for ten years of a person in a developing country who is completely blind.3 According to the DCP2 report, it would cost $1,098 to completely restore, by extracapsular extraction, the sight for ten years of a person in a developing country who is completely blind.
Reference:
| 3. | Curing someone completely of blindness for 10 years is equivalent to averting 6 DALYs, because blindness has a disability weighting of 0.6. (Close footnote) |
The difference between the DCP2's estimate and the WHO-CHOICE's estimate for trachoma surgery is notable. This might be explained by the fact that trachoma surgeries require many goods to be bought at international, rather than local prices; whereas our representation of the WHO assumes that all goods are bought at local prices.
The reasons for the difference between the cost-effectiveness estimates from WHO-CHOICE and DCP2 and estimates from charities themselves are as follows. First, it is possible that the above charities are not quoting the ‘all things considered’ cost of a surgery (that is, including transport, administration costs etc). Secondly, many people who undergo surgery were partially sighted before the operation; and thirdly, many of them are very elderly and thus do not gain as many years of sight as one might expect.
For these reasons, we believe the charities' estimates are compatible with the DCP2 and WHO-CHOICE estimates.
Other Information
All health interventions have side-effects, both good and bad.
Some of the possible side-benefits of eye surgeries include:
- They have good economic benefits: care is no longer needed for the patient, who is able to become economically productive again.
- They have little effect on increasing the population of a country.
One possible side-cost is:
- They may reduce the number of surgeons working in other areas: changing who gets treated for what, but not changing how many people get treated.4
Reference:
| 4. | See for example, the GiveWell article 'Developing World Corrective Surgery' (Close footnote) |
Conclusion
Charities which focus on eye surgeries certainly do a lot of good for a lot of people, with little risk of bad side-effects. However, on the evidence currently available, eye surgery charities seem to be less cost-effective than gold-standard interventions such as bed nets to prevent malaria or drug treatments for neglected tropical diseases . As such, eye-surgery charities are not cost-effective enough for us to give them our highest recommendation; and we suggest that donors should consider other intervention types.
