Posterior%20Corneal%20Elevation%20Measured%20by%20Pentacam%20rotating%20Scheimpflug%20Camera%20associated%20to%20Amsler-Krumeich%20Classification%20for%20Keratoconus.

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Posterior Corneal Elevation Measured by Pentacam
rotating Scheimpflug Camera associated to
Amsler-Krumeich Classification for Keratoconus.

• Henriquez Maria MD, Izquierdo Jr Luis MD,
  Bernilla César MD.
• Authors have no financial interest
• Instituto de Ojos OFTALMOSALUD
• Lima-Perú

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PURPOSE

• The purpose of this study was to measure
  anterior and posterior corneal elevation values
  in patients with keratoconus diagnoses and to
  correlate these values with the Amsler-Krumeich
  classification for keratoconus.

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METHODS

• This prospective study involved 103 eyes with
  keratoconus diagnoses between September 2006
  until June 2008.
• INCLUSION CRITERIA
• Keratoconus diagnoses by biomicroscopic and
  topographic signs.
• Keratoconus cases with a history of corneal
  surgery or with extensive corneal scarring were
  excluded.
• A single expert examiner, who was blind to the
  clinical condition of the patient, acquired
  Pentacam images using the Pentacam rotating
  Scheimpflug camera, software version 2.0. Then
  the anterior and posterior elevation values were
  correlated with the Amsler Krumeich
  classification for keratoconus.

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RESULTS
STAGE OF KERATOCONUS MEAN ANTERIOR ELEVATION VALUE ( um) STANDAR DESVIATION ( DS ) MEAN POSTERIOR ELEVATION VALUE STANDAR DESVIATION ( DS )
I 7.16 5.36 11.49 9.05
II 15.54 5.71 24.72 10.41
III 22.78 7.03 32.11 8.08
IV 37.50 26.49 59.90 37.22

• Mean anterior and posterior corneal elevation
  value was statistically higher in keratoconus
  stage IV (p0.00) compare with stage II and I.

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STAGE I KERATOCONUS
81.3
78.9
Mean 11.49 um
Mean 7,16 um
41.8
39.5
30.2
25.5
13.9
23.2
Corneal anterior elevation value (um)
Corneal posterior elevation value (um)
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EXAMPLE Keratoconus Stage I RX -4,00 -1,00
25
45.85D
8um
7um
8um
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STAGE II KERATOCONUS
48.6 ( 20 - 30 um)
79 (6-20 um)
Promedio 24.72 um
Promedio 11.49 um
25.6
35.5
23
25.6
17.9
12.8
Corneal anterior elevation value (um)
Corneal posterior elevation value (um)
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EXAMPLE Keratoconus Stage II Rx -1.00
-5.00 10
51.84D
25 um
38 um
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STAGE III KERATOCONUS
77.8 ( 20 - 30 um)
66.6 (25 - 35 um)
Promedio 22.78 um
Promedio 32.11 um
55.6
33.3
33.3
22.2
11.1
11.1
25-30
20-25
35-40
40-45
30-35
20-25
35-40
30-35
25-30
Corneal posterior elevation value (um)
Corneal anterior elevation value (um)
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STAGE VI KERATOCONUS
Promedio 37.5 um
Promedio 59.9 um
40
40
20.0
Corneal anterior elevation value (um)
Corneal posterior elevation value (um)
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EXAMPLE Stage IV Keratoconus.
78.49D
82 um
132 um
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CONCLUSION

• Posterior corneal elevation very effectively
  discriminates keratoconus stage VI from
  keratoconus stage II and I. Its efficacy is lower
  for discriminates keratoconus stage II and III
  and thus data concerning posterior elevation
  should be used to help us in stratify patients
  with this condition.