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SYMPTOMS
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Blur | Distorted vision | Image ghosting
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SIGNS
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Corneal thinning and protrusion | Vogt striae | Irregular astigmatism | Munson sign | Fleischer ring | Scarring | Corneal hydrops in severe cases | Topography shows corneal elevation
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WORK-UP
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Thorough history and slit lamp examination | Topography/tomography is recommended | Retinoscopy may reveal a scissor reflex
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Mild KCN may be managed visually with glasses and/or soft contact lenses | Moderate-Severe KCN may be better managed with rigid gas permeable (preferably a KCN-specific RGP like Rose K2), hybrid, or scleral lenses | Progresive keratoconus should be monitored closely with topography/tomography with consideration for corneal cross-linking if progression can be determined
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Intracorneal ring segments are sometimes used | Corneal hydrops warrants a more involved treatment plan | Advanced cases may undergo corneal transplants
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FOLLOW-UP
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Every 3-6 months for KCN suspicion | Stable, non-progressive KCN may be monitored every 6-12 months.
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ETIOLOGY
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Unknown | Association with atopy, Turner syndrome, floppy eyelid syndrome, Down syndrome, Osteogenesis imperfecta, Marfan syndrome, Ehlers-Danlos syndrome | There may be a connection with vigorous eye rubbing
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DIFFERENTIAL DX
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Pellucid marginal degeneration | Keratoglobus | Post-LASIK ectasia
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