Pseudokeratoconus caused by rosacea

Purpose. A case of inferior corneal thinning and high astigmatism with features of keratoconus in a patient with long-standing ocular rosacea is described. Methods. Axial curvature mapping was performed with the Tomey TMS-1 videokeratoscopy instrument and corneal thickness mapping was performed with the Orbscan Corneal Topography System (CTS). Tear clearance was assessed by measuring the concentration of fluorescein in the tear fluid with a fluorometer. Results. There were inferior corneal thinning and opacification in both eyes. Tear fluorescein clearance was markedly delayed in the right eye. There was asymmetric inferior corneal steepening in both eyes with I-S values of I in the right eye and 5.9 in the left eye. There were 5.9 diopters of astigmatism at 85 degrees in the right eye and 7.3 diopters of astigmatism at 73 degrees in the left eye. Corneal pachymetry mapping with the Orbscan CTS showed a normal central corneal thickness and maximal thinning in the inferotemporal periphery of the right cornea and inferonasal periphery of the left cornea. Conclusion. Chronic ocular rosacea can produce inferior corneal thinning and high astigmatism with some features of keratoconus. The inferior pattern of thinning in rosacea may be related to chronic exposure of the inferior cornea to inflammatory and matrix-degrading factors in the inferior tear meniscus.