Table 1

World Health Organization classification of corneal opacity^10,¹¹

Detailed system¹¹	Simple system¹⁰	Definition
0	0	No scarring
1	0	Minimal scarring or opacity but not involving the visual axis, and with clear central cornea
2	CO	Moderate scarring or opacity involving the visual axis, with the pupillary margin visible through the opacity
3	CO	Severe central scarring or opacity with the pupillary margin not visible through the opacity