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

2. Rio de Janeiro Corneal Tomography and Biomechanics Study Group 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.

3. Rio de Janeiro Corneal Tomography and Biomechanics Study Group Purpose  To assess the tomography and biomechanical findings among cases with concomitant keratoconus and corneal guttata.

4. Rio de Janeiro Corneal Tomography and Biomechanics Study Group 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.

5. Rio de Janeiro Corneal Tomography and Biomechanics Study Group 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:

6. Rio de Janeiro Corneal Tomography and Biomechanics Study Group Results All cases showed typical changes of keratoconus on elevation maps tomography  Tomography Findings:

7. Rio de Janeiro Corneal Tomography and Biomechanics Study Group Results  Tomography Findings: The mean of keratometric measures found in patients with keratoconus associated with corneal guttata were similar than normal corneas.

8. Rio de Janeiro Corneal Tomography and Biomechanics Study Group Results  Tomography Findings: 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 typical of corneal guttata

9. Rio de Janeiro Corneal Tomography and Biomechanics Study Group Results  Biomechanical Findings: Signal Time Response Time Signal Analysis The mean of corneal biomechanics measures found in patients with keratoconus associated with corneal guttata were lower than normal corneas.

10. Rio de Janeiro Corneal Tomography and Biomechanics Study Group Conclusions Keratoconus may coexist with corneal guttata. The characterization of tomographic and biomechanical changes may be different from keratoconus and corneal guttata cases.