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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.
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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.
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy 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.
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy Group
Purpose
To assess the tomography and biomechanical findings among cases with concomitant keratoconus and corneal guttata.
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy 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.
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy 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:
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy Group
Results
All cases showed
typical changes of
keratoconus onelevation maps
tomography
Tomography Findings:
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy Group
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.
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy Group
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
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy Group
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.
Rio de Rio de Janeiro Janeiro Corneal Corneal
Tomography Tomography andand
BiomechanicsBiomechanicsStudy GroupStudy Group
Conclusions
Keratoconus may coexist with corneal guttata. The characterization of tomographic and biomechanical
changes may be different from keratoconus and corneal guttata
cases.