Abstract
Purpose: :
to evaluate changes of anterior chamber morphology in keratoconic patients using Pentacam.
Methods: :
41 eyes of 24 keratoconic patients and 68 eyes of 41 age and sex matched control healthy subjects were analysed using Pentacam. Anterior chamber depth centrally (ACDc) and 1 and 3 mm paracentrally (ACD1, ACD3), anterior chamber angle (ACA), anterior chamber volume (ACV), central and minimum corneal thickness (CCT, MCT), anterior and posterior elevation of the cornea, corneal volume in the 3 and 5 mm area (CV3, CV5) were measured and analysed. Data were expressed as mean±SD, due to non-normality of the data the groups were compared using Mann-Whitney W-test, correlation analysis was performed using Spearman rank correlation test; p<0.05 was set as a significance level in all analyses. Area under the Receiver Operator Characteristic Curve (AUROC) were used to determine the most characteristic parameters of the presence of the disease.
Results: :
in the keratoconic group, values of keratometry (48.2±4.96 vs 43.39±1.33 D), anterior (32.88±28.29 vs 2.69±2.34 µm) and posterior (55.42±33.82 vs 5.69±5.52 µm) elevation, ACDc (3.21±0.36 vs 2.84±0.55 mm), ACD1 (3.16±0.29 vs. 2.82±0.57 mm), ACD3 (2.43±0.35 vs. 2.12±0.61 mm) were significantly higher; CCT (491.93±42.86 vs 555.07±22.91 µm), MCT (465.63±54.05 vs 552.45±28.41 µm), CV3 (3.57±0.28 vs 4.02±0.21 mm3), CV5 (10.75±0.68 vs 11.75±0.61 mm3) were significantly lower compared to controls. There was no difference in ACA and ACV between the two groups (p>0.05). In keratoconic patients ACDc significantly correlated with keratometric results (r=0.39), CCT (r=-0.41), MCT (r=-0.60) and to maximal anterior (r=0.58) and posterior (r=0.64) elevation of the cornea. ROC curves defined CV3 as the most sensitive variable for detection of the disease (AUROC: 0.90), followed by CV5 (AUROC:0.88) and ACDc (AUROC: 0.73).
Conclusions: :
increased anterior chamber depth of keratoconic patients is the result of the conic elevation of the cornea and correlates with disease severity as assessed by keratometric, corneal thickness and elevation data. Pentacam is a precise diagnostic tool allowing detailed detection of morphological changes of the cornea and anterior chamber characterizing keratoconus.
Keywords: keratoconus • anterior chamber