ABSTRACT
· AIM:To evaluate the corneal densitometry in treatmentnaive patients with keratoconus and its relevance with anterior and posterior corneal elevation.· METHODS:Keratoconic corneas were examined using the Pentacam.Corneal densitometry was measured over a 12-mm diameter area,divided by annular concentric zones and depths,more over anterior and posterior corneal elevation was measured.Keratoconus was classified according to the topographic keratoconus classification.· RESULTS:A total of 152 subjects [72 patients with keratoconus (46 male,26 female) and 80 healthy control subjects (50 male,30 female)] were included in the study.There were significant differences in corneal densitometry values of the groups in central 2 mm keratoconus (KC)=19.62±4.17 gray scale unit (GSU),N=15.38±1.54 GSU(P＜0.0001),and in annulus of 2 to 6 mmin diameter (K=16.40±2.18 GSU,N=15.31±1.25 GSU,P＜0.0001).When densitometry values for different depths were examined,the anterior layer presented the highest value (KC =23.69±3.71 GSU,N =20.91 ±2.52 GSU,P＜0.0001),which was significantly higher than the values obtained in the central and posterior layer (KC =14.34± 1.70 GSU,N=13.61±1.21 GSU,P=0.001 and KC=11.40± 1.23 GSU,N =12.35±0.88,P=0.002 respectively).Analysis of the correlation between corneal densitometry for each layer depth (anterior,central and posterior) with posterior corneal elevation values demonstrated significant association (r =0.293,r =0.278 and r =0.294 respectively).The similar correlation was not found between corneal densitometry for each layer depth and anterior corneal elevation (r=-0.211,r=-0.101,r=0.99 respectively).In the control patients such a significant correlation between posterior/anterior corneal elevation and corneal light backscatter for each layer depth was not found.· CONCLUSION:The densitometry map reveals that light backscatter was higher in the central portion of the anterior keratoconic cornea.Corneal densitometry values of keratoconus patients were correlated with posterior corneal elevation in 0-2,6-10 and 10-12 annuli and in all anterior,central and posterior layers.The densitometry level was higher in more advanced stages.