Risk Assessment for Corneal Ectasia following Photorefractive Keratectomy

Table 1

The ectasia risk score system (ERSS) for ectasia following LASIK^a [13].

Parameter	Points
	4	3	2	1	0
Topography	FFKC^b	Inf. steep.^c	—	ABT^d	Normal/SBT^e
RSB^f (μm)	<240	240 to 259	260 to 279	280 to 299	>300
Age (years)	—	18 to 21	22 to 25	26 to 29	>30
Pachymetry (μm)	<450	451 to 480	481 to 510	—	>510
SEQ^g (D)	>−14	>−12 to −14	>−10 to −12	>−8 to −10	≤−8
Low risk: 0–2 points; Moderate risk: 3 points; High risk: ≥4 points

^aLaser-assisted in situ keratomileusis; ^bforme fruste keratoconus; ^cinferior steepening; ^dasymmetric bowtie; ^esymmetric bowtie; ^fresidual stromal bed; ^gmanifest refraction spherical equivalent.