الفهرس 
Anatomy of the corneaOnly 14 pages are availabe for public view
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Abstract
Central corneal thickness is a widely used diagnostic parameter for planning refractive surgery and for accurate IOP assessment in ocular hypertension and glaucoma.
Several pachymetry devices are available. USP was considered the gold standard years ago. However, non-contact methods are now preferred for many reasons. Pentacam and AS OCT are two optical non-contact methods which are currently used for AS imaging. Both are capable of obtaining corneal thickness maps in addition to CCT.
The aim of our study was to assess the diagnostic accuracy of Pentacam, AS OCT and USP in measuring CCT in healthy corneas, KC and corneal scars.
The study design was prospective cross-sectional study. Our study included three groups; normal, KC and scars. Each included 20 eyes. For all patients we did Pentacam, AS OCT and the USP after history taking and slit lamp examination.
Our study achieved its primary outcome which was to compare the three devices regarding CCT and we found high agreement in the normal corneas but in the other groups we found that AS OCT measurements are higher than those of Pentacam in most of the cases and USP measurements are higher than Pentacam and AS OCT in corneal scars.
We also studied TCT and TL distance measured with Pentacam and AS OCT and we found agreement between both regarding TCT in the three groups however, there was significant difference regarding TL distance in the three groups. AS OCT failed to obtain thickness map in six KC cases and seven cases with corneal scars while Pentacam was able to obtain maps from all cases.
We also reached our secondary outcome which was to assess the diagnostic accuracy of Pentacam and AS OCT regarding measurement of intracorneal interface or scar depth and we found high agreement between both devices. To our knowledge this was the first study to compare Pentacam and AS OCT in scar depth assessment.