Rio de Janeiro Corneal Tomography and Biomechanics Study Group CORNEAL TOMOGRAPHY AND BIOMECHANICAL FINDINGS OF CONCOMITANT KERATOCONUS AND CORNEAL GUTTATA

Rio de Rio de Janeiro Janeiro Corneal Corneal

Tomography Tomography andand

BiomechanicsBiomechanicsStudy GroupStudy Group

CORNEAL TOMOGRAPHYAND BIOMECHANICAL FINDINGS

OFCONCOMITANT KERATOCONUS

AND CORNEAL GUTTATA

Dr. Ambrósio is consultant for Oculus Optikgeräte GmbH (Wetzlar, Germany)

Isabela Delpizzo, Isaac C. Ramos,Bruno de F. Valbon, Leonardo N.

Pimentel, Diogo L. Caldas, Ana Laura C. Canedo,

Renato Ambrósio Jr.




Introduction

Keratoconus is a progressive, noninflammatory corneal stromal thinning disorder that leads to corneal ectasia, with irregular myopic astigmatism and a variable degree of visual impairment as early as the second decade of life.

Corneal guttata consists on focal accumulations of collagen in the posterior surface of Descemet's membrane. It arises from abnormal endothelial cells, and show up as small rounded blisters prominent toward the endothelium. The Descemet's membrane becomes noticeably thickened, gray and irregular, and may occur endothelial decompensation with secondary edema.




Purpose

To assess the tomography and biomechanical findings among cases with concomitant keratoconus and corneal guttata.




Methods Twenty-two eyes from eleven patients with confirmed diagnosis of keratoconus associated corneal guttata were selected. Complete ophthalmic examination along with Scheimpflug based corneal tomography (Pentacam, Oculus), specular microscopy (LSM 12000, Bio-Optics) and the non contact tonometry system with corneal biomechanical measurements (Reichert ORA) were performed.




Results

All cases had a second peak on corneal densito-metry at the level of the Descemet’s membrane (Camel’s second hum sign), and characteristic pattern of cornea guttata in specular microscopy.

Tomography Findings:




Results

All cases showed

typical changes of

keratoconus onelevation maps

tomography

Tomography Findings:




Results

K1 K2 K máx

Min 39,7 42,4 43,5

Avg 44,4 46 47,6

Max 50,6 53,5 55,8

SD 2,5 2,6 3,1

Tomography Findings: The mean of keratometric measures found in patients with keratoconus associated with corneal guttata were similar than normal corneas.




Results Tomography Findings:Pachy Apex Pachy Min PPI Min PPI Med PPI Max

Min 398 387 0,2 0,7 0,8

Avg 482,5 474,4 0,8 1,2 1,7

Max 585 577 2 2,7 4,6

SD 52,1 50,3 0,4 0,5 0,9 Corneal Thickness

Corneal edema due to guttata can be obscured by concurrent corneal thinning seen in keratoconus, and

low pachymetry may be masked by increased stromal hydration secondary to guttata.

Rectified pattern typicalof corneal guttata




Results Biomechanical Findings:

CRF CH IOPg IOPcc

Min 3,4 4,1 6,2 10,1

Avg 7,6 8,2 12,5 15,7

Max 11,3 10,9 25,8 28,6

SD 2,4 2 4,7 4,4

Signal Time Response

Time

Sig

nal A

naly

sis

The mean of corneal biomechanics measures found in patients with keratoconus associated with corneal guttata were lower than normal corneas.




Conclusions

Keratoconus may coexist with corneal guttata. The characterization of tomographic and biomechanical

changes may be different from keratoconus and corneal guttata

cases.

Documents

Rio de Janeiro Corneal Tomography and Biomechanics Study Group CORNEAL TOMOGRAPHY AND BIOMECHANICAL FINDINGS OF CONCOMITANT KERATOCONUS AND CORNEAL GUTTATA