Accuracy of anterior and posterior curvature decentration indices

Session Details

Session Title: Imaging II

Session Date/Time: Tuesday 13/09/2016 | 14:00-16:00

Paper Time: 14:06

Venue: Hall C1

First Author: : M.Roshdy EGYPT

Co Author(s): :    S. Wahba                    

Abstract Details

Purpose:

To study the accuracy of different curvature decentration indices; anterior corneal curvature (A) Inferior minus Superior value (IS) astride both horizontal meridian (h) and flattest meridian (f), posterior corneal curvature (P) IS value astride both h and f meridian, Index of Height Decentration (IHD) and thinnest point (TP) displacement.

Setting:

Al-Watany Eye Hospital, Cairo, Egypt.

Methods:

In a retrospective study, history taking, clinical examination, and rotating Scheimpflug camera scanning (by Oculyzer II equivalent to Pentacam HR) were done to 94 eyes; 57 normal, 17 keratoconus (KC) and 20 forme fruste keratoconus (FFKC) defined as fellow eye of KC. All cases of corneal scars or previous corneal surgeries were excluded. IS value was calculated manually from 10 points astride the horizontal and flat meridians for both anterior and posterior corneal curvature. IHD and TP displacement were displayed automatically by the device software. The area under the receiver operating characteristic curve (AUROC) was calculated for these decentration indices.

Results:

P-IS-f, P-IS-f, A-IS-f, A-IS-h, IHD, and TP displacement were 1.38±3.79, -1.25±3.83, 0.1±0.6, 0.19±0.62, 0.113±0.794, and 0.69±0.23 in normal corneas and 0.46±0.48, 0.45±0.5, 1.64±1.94, 2.19±3.03, 0.032±0.041, and 0.92±0.36 in KC and FFKC, respectively. When differentiating normal from both FFKC and KC eyes, the index with highest AUROC was P-IS-h followed by A-IS-f, A-IS-h, IHD, TP displacement, and P-IS-f (AUROC= .817, .806, .805, .787, .708, .696 respectively). There were no statistically significant differences between their AUROC except that P-IS-f was inferior to P-IS-h and A-IS-h (P=.014 and .047, respectively)

Conclusions:

The most accurate curvature decentration indices is P-IS-h and the least is P-IS-f. It is recommended to add at least one of the IS indices to the software of Pentacam HR

Financial Disclosure:

... travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, ... travel has been funded, fully or partially, by a competing company