Preoperative conditions of patients in two groups
| Preoperative conditions | Recanalisation of nasolacrimal duct obstruction | External dacryocystorhinostomy |
| n (percentage of total (506)) | n (percentage of total (135)) | |
| Total | 506 (100.0%) | 135 (100.0%) |
| Nasolacrimal duct obstruction | 125 (24.80%) | 51 (37.78%) |
| Chronic dacryocystitis | 255 (50.40%) | 72 (53.33%) |
| Mucocoele | 14 (2.77%) | 2 (1.48%) |
| Fistulae | 10 (1.98%) | 0 (0%) |
| Small lacrimal sac | 45 (8.80%) | 0 (0%) |
| Atrophic rhinitis | 8 (1.58%) | 0 (0%) |
| Failed in external dacryocystorhinostomy | 23 (4.55%) | 3 (2.22%) |
| Failed in silicone intubation | 26 (5.14%) | 7 (5.19%) |