Modesto / Stockton Keratoconus Specialist – Dr. Ash
Keratoconus Evaluation with Visante OCT
A 42 year-old male patient with history of keratoconus presented for a follow-up examination. Corneal Transplant surgery for the right eye had been performed 5 years prior. Left eye that is presented here has been stable and has shown little no change in refraction for year. Patient is perfectly happy with his vision and only uses mild pair of glasses.
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The standard anterior axial curvature map from the ATLAS is in the top left corner. The anterior mean curvature map in the bottom left. The anterior elevation map compared to a best fit sphere is in the top right. All the above three maps are directly imported from the ATLAS Corneal Topographer. They all show that there is a significant corneal steepening (inferiorly and nasally) and bulge in the inferior and slightly temporal position. It is to be noted that the Anterior Axial Curvature map shows the "hot spot" nasal to the thining (as determined by the Pachymap), yet the Anterior Mean Curvature map shows the "hot spot" right in the same location as that of the pachymap.
The Visante Anterior Segment OCT reveals the pachymetric map in the top center. This map shows there is a warped thickness distribution. Rather than the normal that has perfect central thinnest spot with concentric thickening toward the periphery, this map shows an inferior thinning. When compared to a larger normal population, the overall thickness is not too far below average over the entire cornea but there is a large "Hot Spot" in the inferior and slightly temporal position.
In the Visante omni, the posterior elevation relative to a best fit sphere, a corresponding forward bulge on the inner aspect of the cornea is confirmed and is noted to be approximately 54 microns.
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In this image, the same patient is presented with the assumption of a best fit Toric Ellipsoid rather than a sphere. Given the overall shape of the cornea, one can note only minor differences if any and still the diagnosis of Keratoconus firmly prevails. Also of note, in the Holladay report above the anterior tangential map replaces the anterior mean curvature map in the bottom left side.
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07/04/11