![]() In both eyes, there was a bow-tie-shaped corneal astigmatism with a value of 17.96D in the right eye. Keratometric readings were 53.98D/36.04D in the right eye. The horizontal axis had more normal corneal contour and thickness. Topograph sagittal curvature map on the right eye showed vertical flatting and irregular inferior corneal astigmatism. The vertical axis images showed significant central irregular against-the-rule astigmatism, marked peripheral thinning within 2.0 mm of the limbus, and more normal corneal thickness inferior to the band of thinning. The intraocular pressure measured by noncontact tonometry was in normal range in both eyes.Ĭorneal topography was characteristic for PMD. Corneal thickness measured by ultrasonic pachymeter of the right eye were 502 μm centrally and 520 μm peripherally in the left eye, the readings were 540 μm centrally, and 520 μm at the periphery. ![]() (a and b) Scheimpflug image (Oculus Pentacam HR) of the anterior segment shows irregular shaped central corneal regionīoth anterior chambers were 4.11 mm deep. Scheimpflug image (Oculus Pentacam HR) of the anterior segment of the right eye shows irregular shaped central corneal region. A 2.0-mm zone of normal-thickness cornea was seen between the thinned area and the limbus. However, the left eye showed a clear band of peripheral thinning about 1–2 mm wide, with anterior protrusion of the cornea just above the thinned area. ![]() Between the thinned area and the limbus, the corneal thickness was normal. The lesion was nonulcerative and inflammatory, and implied the protrusion of the cornea. Slitlamp examination of the cornea showed inferior peripheral corneal-thinning without iron lines, vascularization, or lipid deposition. Ophthalmic examination revealed his best-uncorrected visual acuity, a value of +0.8 in the right eye and +0.1 in the left eye observed with a logarithmic scale (LogMAR). Visual acuity, slitlamp examination, corneal thickness map measurement (Pentacam HR, Oculus), and tonometry were carried out, and simulated keratometric (SK1, SK2) and topographic index values were detected with corneal topograph (Tomey TMS4). The patient tried rigid gas-permeable contact lenses but could never get an acceptable fit. He had high blood pressure and type II diabetes mellitus was treated for around 9 years. His right eye was pseudophakic, and his left eye had posterior subcapsular cataract. Earlier, he was diagnosed with glaucoma simplex treated with timolol 0.5%. There was no history of excessive eye rubbing, trauma, contact lens wear, or episodic redness of the eye. A 55-year-old male is presented, complaining of progressive dimness of vision in both eyes with decreased vision started 1 year before examinations at our clinic, but the visual loss was larger in the right eye. We analyzed a case of advanced bilateral PMD patient and treated one eye with corneal CXL. The CXL treatment can stop PMD progression and produce better quality of vision. It was clinically typical bilateral PMD with a characteristic pattern of irregular astigmatism on corneal topography, with chief complaints of progressive dimness of vision caused by irregular astigmatism. Here we present one case showing the features of PMD both clinically and topographically treated by collagen cross-linking (CXL). in 2003 for the treatment of progressive keratoconus and related disorders increasing the biomechanical strength of the cornea by about 300%. Although histopathologically it is considered a variant of keratoconus, it differs in that the marked corneal steepening occurs more inferiorly.Ĭorneal cross-linking was introduced by Wollensak et al. It is differentiated from peripheral corneal disorders associated with inflammation such as Terrien's marginal degeneration and Mooren's ulcer by the absence of vascularisation. It occurs in both men and women and can be differentiated from other peripheral corneal thinning disorders such as keratoconus and keratoglobus by its characteristics that this thinning occurs 1–3 mm from the limbus in the 4–8 o’clock position. Pellucid marginal degeneration (PMD) of the cornea is a progressive, rare, and uncommon noninflammatory corneal disorder characterized by the thinning in the peripheral portion of the inferior cornea with marked steepening just superior to the thinned zone.
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