FFKC criteria 2009

Ming Wang, MD, PhD

Wang Vision 3D Cataract and LASIK Center, Nashville, Tennessee

2 D rule:

1. >  2D difference in superior and inferior k readings outside the central 3mm;
2. >  2D difference in the corresponding inferior corneal locations between two eyes;
3. Absolute value of K very high (over 50D) in one eye;

3-point touch:

1. Coinciding of location of pathology of ant & post elevation, pachymetry & ant curvature;
2. Displaced apex in all maps;

Anterior & posterior float:

1. “Ominous purple” in the posterior surface;
2. Anterior 15-20 um;
3. Posterior 20-25um (post-LASIK: 40-50um);

Pachymetry:

1. Bed 250-300um;
2. Normal: 535um, SD=35um. No LASIK below 1D(500um), no PRK below 2d (465um);
3. KC: 430um, SD=70um;
4. Thinnest area is more than 15um thinner than center;
5. The difference between thinnest areas between  2 eyes is greater than 15-20um;
6. Abrupt &  more rapid “out-of-zone” pachy increase from thinnest point radially out;

IA orientation, amount, pattern:

1. > 3D or more dioptic curvature change, in central 3-mm circle;
2. In central 3-mm circle, not regular (bow-tie) pattern; across the pupil 180 degrees,
3. change of astigmatism orientation and amount;
4. Against-the-rule astig plus inferior steepening, the "C" pattern, suggesting PMD;

Topo-based FFKC detectors:

1. Tomey: positive KC score with either the KCI or KCS index;
2. EyeSys: I-S > 1.3;
3. Pentacam: ISV, IVA, KI, CKI, /Rmi, IHA, IHD and ABR
4. Humphrey Atlas: Path-finder, in red zone.

If you're interested in learning about FFKC criteria, call (615)321-8881 or email Wang Vision 3D Cataract and LASIK Center of Nashville, Tennessee today.