No previous diagnosis of KC (rare to not have known he has keratoconus)
Topographic findings not c/w stable acuity for years
No visual symptoms beyond refractive error
Highly asymmetric presentation between OD and OS (rare)
Implications for Diagnosis
Possible corneal cross-linking
Earlier cataract surgery should be okay
IOL calculations are probably accurate
Fuchs Endothelial Corneal Dystrophy
No cross-linking indicated
Avoid premature cataract surgery as could cause corneal decompensation
IOL calculations may be inaccurate due to induced keratometric steepening from edema
Scheimpflug corneal tomography
Anterior segment optical coherence tomography
Atypical Fuchs Endothelial Corneal Dystrophy
KC is a bilateral non-inflammatory corneal ectasia which typically presents with stromal thinning and inferior steepening on axial / sagittal topography
Fuchs is a progressive disease characterized by the development of corneal edema with increased corneal thickness
The anterior curvature map OS showed inferior steepening classic for KC
The corneal thickness map, however, did not show correlated inferior focal thinning as we would predict in KC; rather it showed correlated thickening (expected in Fuchs)
Avoid premature cataract surgery of the left eye (to avoid corneal decompensation)
Prognosis and Future Directions
The differentiation between concurrent KC and FECD vs. FECD alone can be difficult, as not all focal steepening indicates keratoconus
The differentiation is critical in determining appropriate intervention
Prior cases in the literature have reported concurrent KC and FECD; however, it is possible that many were actually atypical presentations of FECD, but diagnosed as KC
Therefore, Placido topography must be supplemented with regional corneal thickness measurements to achieve the correct diagnosis and guide appropriate intervention
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