Over every point of a central region of the cornea. A novel contribution of this paper is the computation of the We present evidence that currently used curvature maps do not represent the actual curvatures (principal or mean) in a human cornea. Metrics for diagnosis typically employed are curvature maps (axial/sagittal, tangential) elevation map of the anterior surface of the cornea with respect to a reference sphere and pachymetry (thickness) map of the cornea. Identification of objective criteria to correctly diagnose ectatic diseases of the cornea or to detect early stages of corneal ectasia is of great interest in ophthalmology and optometry. At the moment, there is no unanimity with regards to the optimum surgical treatment of PMD and larger prospective studies will be required to form a more robust algorithm for the surgical approach of PMD individuals whose vision cannot be corrected with spectacles or contact lenses. To date, there are no large prospective interventional studies to elucidate the optimum surgical approach for advanced PMD, only case reports or case series.Ĭonclusion: Eye care practitioners need to be aware of the clinical and topographic findings of this disease, since laser refractive surgery is a contraindication. Management of PMD includes the use of contact lenses, spectacles and a wide range of surgical techniques with variable results. PMD patients are at risk of corneal perforation after minimal ocular trauma or even spontaneously.
It mainly affects the inferior cornea and induces against the rule irregular corneal astigmatism. Results: PMD is a rare ectatic disorder of the cornea that may resemble keratoconus especially at the early stages. Materials and Methods: Literature review via PubMed, Mendeley, Scopus and Google Scholar. Purpose: To describe the clinical features of Pellucid Marginal Degeneration (PMD) and to give an overview of current treatment options. This review describes the clinical features of PMD, its differential diagnosis and various management strategies presently available. Since patients with PMD make poor candidates for laser vision correction, an awareness of the topographical and slit-lamp features of PMD will be useful to clinicians screening for signs of corneal abnormality before corneal refractive surgery. Several surgical procedures have been used in an attempt to improve visual acuity when spectacles and contact lenses do not provide adequate vision correction. The vast majority of PMD patients are managed using spectacles and contact lenses. In rare cases, patients may present with a sudden loss of vision and excruciating ocular pain due to corneal hydrops or spontaneous perforation. Visual signs and symptoms include longstanding reduced visual acuity or increasing against-the-rule irregular astigmatism leading to a slow reduction in visual acuity. Unless corneal topography is evaluated, early forms of PMD may often be undetected however, in the later stages PMD can often be misdiagnosed as keratoconus. Ocular signs and symptoms of patients with PMD differ depending on the severity of the condition. The prevalence and aetiology of this disorder remain unknown. The condition is most commonly found in males and usually appears between the 2nd and 5th decades of life affecting all ethnicities. Pellucid marginal corneal degeneration (PMD) is a rare ectatic disorder which typically affects the inferior peripheral cornea in a crescentic fashion.
0 kommentar(er)
