Variation in cataract surgical rate by State and over time in Nigeria
| State | Geopolitical zone | Cataract operations/million population/year | |
| Kwara13 | Northcentral | 218 in 2003 | 1020 in 2009 |
| Sokoto14 | Northwest | 272 in 2006 | 596 in 2014 |
| Ogun15 | Southwest | – | 1098 in 2014 |