SYMPTOMS Blur | Distorted vision | Image ghosting
SIGNS Corneal thinning and protrusion | Vogt striae | Irregular astigmatism | Munson sign | Fleischer ring | Scarring | Corneal hydrops in severe cases | Topography shows corneal elevation
WORK-UP Thorough history and slit lamp examination | Topography/tomography is recommended | Retinoscopy may reveal a scissor reflex
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
Intracorneal ring segments are sometimes used | Corneal hydrops warrants a more involved treatment plan | Advanced cases may undergo corneal transplants
FOLLOW-UP Every 3-6 months for KCN suspicion | Stable, non-progressive KCN may be monitored every 6-12 months.
ADDITIONAL LAB | TESTS Topography/tomography
ETIOLOGY 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
DIFFERENTIAL DX Pellucid marginal degeneration | Keratoglobus | Post-LASIK ectasia