This review describes the clinical features of PMD, its differential diagnosis and various management strategies presently available.Ĭopyright © 2010 British Contact Lens Association. 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. Topography of the right eye showed corneal thinning that predominated inferiorly on the pachymetric map.The elevation maps objectified a corneal protrusion. 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. Corneal cross-linking: an effective treatment option for pellucid marginal degeneration.Pellucid marginal corneal degeneration (PMD) is a rare ectatic disorder which typically affects the inferior peripheral cornea in a crescentic fashion. There is a lack of evidence supporting efficacy and stability of CXL in PMD, and well-controlled prospective studies with long-term follow-up are necessary. The authors concluded that CXL seems to be safe and effective in the management of PMD, but existing literature is limited, with short-term follow-up and the retrospective nature of most studies. None of the studies reported any complications, however rare but serious potential complications can occur and should be noted. In the studies, CXL was performed immediately after surface ablation, theoretically combining benefits of both treatments. Combined CXL and laser vision correction demonstrated a greater improvement in uncorrected distance visual acuity (UDVA) vs. Four studies included follow-up duration >1 year. CXL was shown to halt disease progression and stabilise / improve vision in all studies. All of the studies included additional treatments that were used with CXL: photorefractive keratectomy (PRK), phototherapeutic keratectomy (PTK) and intrastromal corneal ring segment (ICRS). decentered grafts closer to limbus confer a greater risk of vascularisation, suture erosion and rejection). Progression of PMD is important because keratoplasty in PMD is associated with significant comorbidity (e.g. Compared to other corneal thinning conditions like keratoconus, corneal steepening in PMD occurs more inferiorly and closer to the limbus. PMD is a bilateral, non-inflammatory corneal thinning disorder characterised by inferior peripheral corneal thinning 1-3mm from the limbus in the 4 to 8 o’clock position. The word ‘pellucid’, meaning clear, was first used by Schlaeppi 1 to denote the clarity of the cornea in this condition despite the presence of ectasia. Fourteen studies were included in this first review examining the use of corneal-crosslinking (CXL) to treat pellucid marginal degeneration (PMD). Pellucid marginal corneal degeneration (PMD) is a rare idiopathic, thinning disorder of the peripheral cornea most usually affecting the inferior quadrant in a crescentic fashion.
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