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Scheimpflug imaging for keratoconus and ectatic disease.

Belin MW, Ambrósio R - Indian J Ophthalmol (2013)

Bottom Line: Changes on both the posterior cornea and/or corneal thickness map are earlier indicators of ectatic change than would otherwise be identifiable with only anterior curvature and ultrasonic pachymetry.Scheimpflug imaging also covers significantly more of the cornea than was possible with placido based devices.This added coverage is critical in the proper diagnosis of peripheral diseases such as pellucid marginal degeneration (PMD).

View Article: PubMed Central - PubMed

Affiliation: Southern Arizona VA Healthcare System, University of Arizona, Tucson, Arizona, USA.

ABSTRACT
Scheimpflug cross-sectioning anterior segment imaging offers significant advantages over traditional placido based curvature analysis and ultrasound pachymetry. The accurate measurement of both the anterior and posterior corneal surfaces and the anterior and posterior lens allows for the creation of a three-dimensional reconstruction of the anterior segment. Changes on both the posterior cornea and/or corneal thickness map are earlier indicators of ectatic change than would otherwise be identifiable with only anterior curvature and ultrasonic pachymetry. Scheimpflug imaging also covers significantly more of the cornea than was possible with placido based devices. This added coverage is critical in the proper diagnosis of peripheral diseases such as pellucid marginal degeneration (PMD).

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Belin/Ambrosio enhanced ectasia display. The display shows abnormalities in all major parameters except those for the anterior corneal surface. Because the anterior surface is still within normal limits, the patient would have good spectacle vision in the presence of (subclinical) keratoconus
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Figure 4: Belin/Ambrosio enhanced ectasia display. The display shows abnormalities in all major parameters except those for the anterior corneal surface. Because the anterior surface is still within normal limits, the patient would have good spectacle vision in the presence of (subclinical) keratoconus

Mentions: The BAD III displays each parameter and individually reports them as a standard deviation and then reports a final overall reading that is based on a regression analysis to maximize the separation of normal corneas from those with keratoconus. In the example below [Fig. 4], one can see individual abnormalities in both the corneal thickness parameters and on the posterior corneal surface, while the anterior surface parameters remain within normal limits. The combined reading based on the regression analysis of all nine parameters is highly abnormal and diagnostic of subclinical keratoconus, in spite of a normal anterior surface.


Scheimpflug imaging for keratoconus and ectatic disease.

Belin MW, Ambrósio R - Indian J Ophthalmol (2013)

Belin/Ambrosio enhanced ectasia display. The display shows abnormalities in all major parameters except those for the anterior corneal surface. Because the anterior surface is still within normal limits, the patient would have good spectacle vision in the presence of (subclinical) keratoconus
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3775073&req=5

Figure 4: Belin/Ambrosio enhanced ectasia display. The display shows abnormalities in all major parameters except those for the anterior corneal surface. Because the anterior surface is still within normal limits, the patient would have good spectacle vision in the presence of (subclinical) keratoconus
Mentions: The BAD III displays each parameter and individually reports them as a standard deviation and then reports a final overall reading that is based on a regression analysis to maximize the separation of normal corneas from those with keratoconus. In the example below [Fig. 4], one can see individual abnormalities in both the corneal thickness parameters and on the posterior corneal surface, while the anterior surface parameters remain within normal limits. The combined reading based on the regression analysis of all nine parameters is highly abnormal and diagnostic of subclinical keratoconus, in spite of a normal anterior surface.

Bottom Line: Changes on both the posterior cornea and/or corneal thickness map are earlier indicators of ectatic change than would otherwise be identifiable with only anterior curvature and ultrasonic pachymetry.Scheimpflug imaging also covers significantly more of the cornea than was possible with placido based devices.This added coverage is critical in the proper diagnosis of peripheral diseases such as pellucid marginal degeneration (PMD).

View Article: PubMed Central - PubMed

Affiliation: Southern Arizona VA Healthcare System, University of Arizona, Tucson, Arizona, USA.

ABSTRACT
Scheimpflug cross-sectioning anterior segment imaging offers significant advantages over traditional placido based curvature analysis and ultrasound pachymetry. The accurate measurement of both the anterior and posterior corneal surfaces and the anterior and posterior lens allows for the creation of a three-dimensional reconstruction of the anterior segment. Changes on both the posterior cornea and/or corneal thickness map are earlier indicators of ectatic change than would otherwise be identifiable with only anterior curvature and ultrasonic pachymetry. Scheimpflug imaging also covers significantly more of the cornea than was possible with placido based devices. This added coverage is critical in the proper diagnosis of peripheral diseases such as pellucid marginal degeneration (PMD).

Show MeSH
Related in: MedlinePlus