Table 1

MeSH search strategy

Stage 1 Diseases		Stage 2 Drugs		Stage 3 Study methods
1	exp glaucoma or exp glaucoma, open angle	4	exp prostaglandins F, synthetic	7	exp clinical trials or exp randomised controlled trials
2	exp ocular hypertension	5	exp adrenergic β antagonists	8	exp double blind method
3	1 or 2	6	4 and 5	9	exp single blind method
				10	exp random allocation
				11	7 or 8 or 9 or 10
Finally, we combined three stages together using: 3 and 6 and 11