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Ocular media
Published in Fiona Rowe, Visual Fields via the Visual Pathway, 2016
These involve deformation of corneal shape such as keratoconus, keratoglobus and pellucid marginal degeneration. Pellucid marginal degeneration is a non-inflammatory thinning of the inferior corneal periphery.
Corneal ectasia associated with posterior lamellar opacification
Published in Ophthalmic Genetics, 2021
Madeline Yung, Angela C. Chen, Doug D. Chung, Alice Barrington, Junwei Zhang, Ricardo F. Frausto, Otavio A. Magalhaes, Anthony J. Aldave
Corneal ectatic disorders such as keratoconus and keratoglobus are characterized by progressive corneal thinning, steepening, and visual distortion (1,2). In keratoconus, disruption of the anterior corneal lamellae results in conical thinning greatest at the corneal apex, myopia, irregular astigmatism, Descemet membrane tears with acute hydrops, and anterior stromal scarring (3,4). Keratoconus is a complex disorder, associated with variants in over 60 genes, as well as non-ocular conditions, such as atopic disorders and environmental factors (5). Keratoglobus presents with congenital or progressive corneal thinning greatest in the periphery, associated with acute hydrops and a predisposition to corneal perforation following trauma. Similar to keratoconus, keratoglobus is associated with a variety of systemic, environmental, and hereditary risk factors, although a genetic locus has not been identified (6–10).
Posterior amorphous corneal dystrophy in a patient with 12q21.33 deletion
Published in Ophthalmic Genetics, 2018
Janine Lenk, Joseph Porrmann, Martin Smitka, Ines Eger, Evelin Schröck, Karl Hackmann, Robert Herber, Frederik Raiskup, Andreas Tzschach
Ophthalmic investigations by slit-lamp analysis and corneal topography and tomography by Scheimpflug imaging (Pentacam, Oculus, Wetzlar, Germany) revealed bilateral posterior stromal corneal opacification, global thinning and steepening which are compatible with keratoglobus (Figure 1(a,b)). Investigations by Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments, Inc., Buffalo, NY) measurements revealed decreased corneal hysteresis (CH) and corneal resistance factor (CRF) values (Figure 1(c)). Confocal microscopy using the Heidelberg Retina Tomograph – Rostock Cornea Module (Heidelberg Engineering GmbH, Heidelberg, Germany) showed a normal epithelial layer with thin corneal nerves in the deeper layers. The anterior stroma appeared normal, whereas the deeper stroma revealed striae and deposits with higher reflectivity (Figure 1(d)). Keratoglobus was treated at age 5 years by corneal collagen cross-linking as described by Wollensak et al. (9). He also had strabismus concomitans convergens of the left eye. Central corneal pachymetry at age 6 years revealed 263 µm for the right eye and 250 µm for the left eye. Iris, lens, and intraocular pressure were normal. Fundoscopy revealed no abnormalities.