Purpose:
To test the sensitivity of keratoconus screening based on pachymetry maps measured by a commercially-available high-speed corneal and anterior segment optical coherence tomography (OCT) system.
Methods:
The VisanteTM OCT system (Carl Zeiss Meditec, Inc.) was used to measure pachymetry maps. Keratoconus and forme fruste keratoconus (FFK) subjects from the Clinique Monticelli were analyzed retrospectively. The normative database was obtained from a prospective study at the Doheny Eye Institute. The pachymetry maps were obtained with the "Pachymetry Map" scan pattern centered on the vertex (Visante software version 1.0). Parameters were calculated from the central 5 mm diameter. The 2-5 mm annulus was divided into octants.
Results:
Data was obtained from 30 keratoconic eyes of 21 subjects, 14 FFK eyes of 11 subjects, and 36 eyes of 18 normal subjects. Sensitivity and specificity values were measured for the 4 best diagnostic parameters using 1 percentile point (mean - 2.33 standard deviations) as the cutoff (Table).I = inferior octant, S = superior octant, IT = inferotemporal octant, SN = superonasal octant, Min = minimum, max = maximum.
Conclusions:
OCT has good sensitivity for detecting keratoconus using a combination of 4 pachymetry map-derived parameters that detects asymmetry, global thinning and focal thinning. The presence of 2 abnormal parameters is highly specific for keratoconus. OCT May be helpful in the diagnosis of keratoconus.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical • keratoconus