Primary angle closure glaucoma: a developing world perspective.

Primary angle closure glaucoma (PACG) is estimated to affect a significant proportion of the population worldwide. Of those affected, the majority reside in developing countries. In the developing world, more than 80% of the people afflicted with glaucoma are unaware that they have the disease, and visual impairment from PACG is more severe than from primary open-angle glaucoma. Considering the paucity of resources and competing opportunity costs, it is imperative that the developing world extrapolates current literature and exiting data sensibly, and develops cost-effective strategies for the detection and management of angle closure glaucoma. The number needed to treat (NNT) was used to extrapolate the trials for an individual patient. To extrapolate to the overall population (where applicable) the authors used the population attributable risk percentage (PAR%). For individual patient care, treatment of a primary angle closure suspect (PACS) has an NNT of 6 over 5 years to prevent one patient progressing to primary angle closure (PAC). The NNT for PAC to prevent PACG over 5 years is 5. The 'effective' PAR% for PACS is 56.4% and the 'effective' PAR% for PAC is 65%. This suggests both PACS and PAC are important health burdens but because of the absence of a good screening test and the opportunity costs involved, population-based screening will probably be unfeasible in developing countries.