Posters

Corneal tomographic analysis as a clue for corneal biomechanics

Poster Details

First Author: E. El-Mayah EGYPT

Co Author(s):                        

Abstract Details

Purpose:

To investigate the possible associations between corneal tomographic analysis and corneal biomechanical properties in normal myopic patients.

Setting:

Kasr Alainy School of Medicine,Cairo University, Egypt.

Methods:

Cross section study including the right eye of 46 normal myopic patients with ages ranging from 20 to 45 years (28.24 ± 5.51 years) and mean spherical equivalent ranging from -14.50 to -.75 D (–4.93 ± 3.33 D).Pentacam (Oculus GmbH, Wetzlar, Germany) was used to obtain mean keratometric readings,corneal thickness at pachy apex ,keratometric power deviation (KPD), corneal asphericity (Q value within 6 mm diameters) of anterior surface, corneal volume (CV) and corneal higher order aberrations.Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using the Ocular Response Analyser (ORA; Reichert Ophthalmic Instruments, Depew, New York, USA).

Results:

Kolmogorov Smirnov test was used to detect distribution of data.Pearson correlation coefficient was used to detect correlation between all variables except between Q value and CH and CRF,the spearman rank coefficient was used. There was a strong positive correlation between CH, CRF and Pachy apex (CH:r=.538,P=0.0001,CRF: r=0.6,P<.0001), also a strong positive correlation between CH,CRF and mean K reading was found (CH:r=.44, P=0.0023,CRF:r=0.33,P=0.0246). A positive correlation with CV value was also found (CH:r=0.332,P=.024,CRF:r=0.32,P=0.029) within central 6 mm diameter of the cornea.On the other hand, CH and CRF were negatively correlated with age, spherical equivalent, Q value, keratometric power deviation but not statistically significant and positively correlated with spherical aberrations, coma aberrations both vertical and horizontal but also not statistically significant.

Conclusions:

There is a relationship displayed between corneal tomographic analysis and corneal biomechanical properties (CH and CRF). In our research the more steep thick cornea, the more the corneal biomechanical parameters .Also the more the corneal volume(CV), the more the corneal biomechanical prameters giving clues for predicting corneal biomechanics from pentacam. It is recommended to investigate the association between CV and corneal biomechanics in keratoconic patients and keratoconus suspect so putting a cut of point for diagnosis of keratoconus.

Financial Disclosure:

NONE