Brittle Cornea Syndrome: Case Report with Novel Mutation in the PRDM5 Gene and Review of the Literature

Table 2

Amsler-Krumeich classification of keratoconus (modified from [1, 2]).

Classification	Ophthalmological findings
Stage I	Myopia and/or astigmatism <5.0 D
	Mean central corneal readings <48.0 D
	Eccentric corneal steepening
Stage II	Myopia and/or astigmatism 5.0–8.0 D
	Mean central corneal readings <53.0 D
	Absence of scarring
Stage III	Myopia and/or astigmatism 8.0–10.0 D
	Mean central corneal readings >53.0 D
	Absence of scarring
Stage IV	Central corneal scarring
	Minimal corneal thickness 200 m
	Mean central corneal readings >55.0 D
	Refraction not measurable