Table 1.

Amsler–Krumeich classification system

Stage	Findings
1	Eccentric steepening Myopia, induced astigmatism, or both <5.00 D Mean central K readings <48 D
2	Myopia, induced astigmatism, or both from 5.00 to 8.00 D Mean central K readings <53.00 D Absence of scarring Corneal thickness >400 μm
3	Myopia, induced astigmatism, or both from 8.00 to 10.00 D Mean central K readings >53.00 D Absence of scarring Corneal thickness 300–400 μm
4	Refraction not measurable Mean central K readings >55.00 D Central corneal scarring Corneal thickness <200 μm

D diopter, K keratometry