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E. A. Person, J. R. Hausheer; Corneal Topography of Keratoglobus. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4317.
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To describe Atlas and Orbscan topographies in a patient with Keratoglobus.
NW is a 35 year old AAM presenting to clinic with decreased vision of 20/300 despite new glasses and difficulty with comfort and fit of soft contact lenses. Atlas and Orbscan corneal topographies were performed showing marked astigmatism and severe sloping in each eye.
Simulated K values were 75.0 at 90 and 54.87 at 180 for 20.13 D corneal astigmatism in the right eye and 71.25 at 96 and 44.00 at 6 for 27.25 D astigmatism in the left eye using Atlas Version A11.2. Orbscan was performed following dilation with suboptimal results related to dilation and applanation tonometry corneal changes. It showed spherical power of 37.42 D with -67.63 D cylinder in the right eye, and spherical power of 66.90D with +40.95D cylinder in the left eye. The white-to-white was 11.5 and 11.4 right and left eyes respectfully. Optical corneal pachymetry showed marked thinning centrally (262 microns) in the right eye and more thinning inferiorly (271 microns at 6 o’clock in the 7mm zone) than centrally (432 microns) in the left eye. Atlas and Orbscan studies were limited by mild ptosis in this patient which may have also induced greater astigmatism. These were both technically difficult tests to complete in this individual and ideally should be repeated undilated with digital eyelid retraction or a lid speculum.
Keratoglobus is a rare bilateral congenital corneal ectasia with decreased vision and surface abnormalities. It demonstrates a uniformly thinned cornea with a deep anterior chamber and should be differentiated from both keratoconus and megalocornea. Atlas and Orbscan studies have not previously been described in this condition, but could assist in diagnosis of keratoglobus.
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