Posters

Presentation patterns of peripheral anterior and posterior curvature maps in normal corneas and corneas with keratoconus

Poster Details

First Author: C. Arce BRAZIL

Co Author(s):    A. dos Santos Forsetto   L. Pedral Sampaio   L. Bocchese   N. Cesario Pereira           

Abstract Details

Purpose:

To study and describe the peripheral patterns of 10-mm-diameter anterior and posterior tangential maps with a modified color scale and the dual Scheimpflug and Placido corneal analyzer

Setting:

Eye Bank Hospital of Sorocaba, São Paulo, Brazil

Methods:

Anterior and posterior 10-mm-diameter tangencial maps were set with the 1D-CGA German scale in the dual Scheimpflug and Placido corneal analyzer (Galilei). We studied the variability of the peripheral patterns of anterior and posterior tangential maps between 6- to 10-mm-diameter. Patterns were described and classified in 50 normal corneas and 50 corneas with keratoconus from 100 patients at the Eye Bank Hospital of Sorocaba, São Paulo, Brazil.

Results:

The modified color scale in tangential maps allowed an easy view and demarcation of an extreme anterior peripheral flattening below 36D found more frequently in corneas with keratoconus than in normal corneas (P<0.01). This anterior flattening may happen in none, or in one, two,three or four quadrants, contiguous or not, and usually beyond 8-mm-diameter but may be also found more centrally in some corneas with keratoconus. Posterior surface have a different peripheral normal pattern than anterior surface with a typical flatter ring zone between 7 to 8-mm-diameter followed with a classical steepening beyond that

Conclusions:

While patterns of central curvature maps are well known, information about their periphery is scarce. The differences found between normal corneas and corneas with keratoconus may be a novel sign of how some corneas deform according to the vector forces, their strength and the biomechanical failure that happen in corneas with keratoconus. The dimensions of the central and peripheral zones described in these maps are similar with those showed for the Dua's layer suggesting a possible relation with the type of big bubble formed during DALK. We have an ongoing study searching if this sign may guide this surgery

Financial Disclosure:

One or more of the authors receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, One or more of the authors travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented