Articoli Scientifici di Oftalmologia
Argomento : 2
Epithelial, Stromal, and Total Corneal Thickness in Keratoconus: Three-Dimensional Display with Artemis Very-High Frequency Digital Ultrasound
ABSTRACT
PURPOSE: To characterize the epithelial, stromal, and
total corneal thickness profi le in a population of eyes
with keratoconus.
METHODS: Epithelial, stromal, and total corneal thickness
profi les were measured in vivo by Artemis very
high-frequency (VHF) digital ultrasound scanning (ArcScan,
Morrison, Colo) across the central 6- to 10-mm
diameter of the cornea on 54 keratoconic eyes. Maps
of the average, standard deviation, minimum, maximum,
and range of epithelial, stromal, and total corneal
thickness were plotted. The average location of the thinnest
epithelium, stroma, and total cornea were found.
The cross-sectional semi-meridional stromal and total
corneal thickness profi les were calculated using annular
averaging. The absolute stromal and total corneal
thickness progressions relative to the thinnest point
were calculated using annular averaging as well as for 8
semi-meridians individually.
RESULTS: The mean corneal vertex epithelial, stromal,
and total corneal thicknesses were 45.75.9
µm, 426.438.5 µm, and 472.241.4 µm, respectively.
The average epithelial thickness profi le showed
an epithelial doughnut pattern characterized by localized
central thinning surrounded by an annulus of thick
epithelium. The thinnest epithelium, stroma, and total
cornea were displaced on average by 0.480.66 mm
temporally and 0.320.67 mm inferiorly, 0.310.45
mm temporally and 0.540.37 mm inferiorly, and
0.310.43 mm temporally and 0.500.35 mm inferiorly,
respectively, with reference to the corneal vertex.
The increase in semi-meridional absolute stromal and
total corneal thickness progressions was greatest inferiorly
and lowest temporally.
CONCLUSIONS: Three-dimensional thickness mapping
of the epithelial, stromal, and total corneal
thickness profi les characterized thickness changes
associated with keratoconus and may help in early diagnosis
of keratoconus. [J Refract Surg. 2009;xx:xxx-xxx.]
DOI:1.9999/1081597X-200905015-06