History

• Chief Complaint: Blurred vision right eye only presents for cataract evaluation
• 56 year-old male with longstanding Fuchs endothelial corneal dystrophy (FECD) OU and previously diagnosed cataracts OU, complaining of progressive blurry vision OD for the past few months (OS stable)
• He had minimal additional symptoms related to corneal edema (no reported morning blur, minimal visual fluctuations)

Exam Findings

• VAcc: 20/50+ 2 OD 20/20-1 OS
• Refraction: -6.75 OD, -4.00 OS
• IOP: 18mmHg OD 14mmHg OS
• SLE Notable for:
• K guttata OU, no obvious edema in either eye
• Lens NSC 2+ OD ½ + OS

Additional Investigations

• IOL Calculations
• Corneal Placido disc-based Topography

Patient Course

• Patient received CE/IOL OD – uneventful
• Postoperative week 1: UDVA= 20/20 OD
• Patient content with results and requested cataract removal of left eye

Differential Diagnosis

• Keratoconus (KC) + Fuchs Endothelial Corneal Dystrophy (FECD)
• Corneal topography classic for KC
• High astigmatism on the IOL Master (~5D)
• Refraction c/w moderate myope with astigmatism
• Fuchs Endothelial Corneal Dystrophy alone (FECD)
• Good acuity with glasses
• 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

• Keratoconus
• 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

Additional Investigations

• Scheimpflug corneal tomography
• Anterior segment optical coherence tomography

Diagnosis

• Atypical Fuchs Endothelial Corneal Dystrophy

Pathophysiology

• 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)

Treatment

• 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

References

• Rabinowitz YS. Keratoconus. Survey of Ophthalmology. 1998 Jan 1;42(4):297-319.
• Gain P, Jullienne R, He Z, et al. Global survey of corneal transplantation and Eye banking. JAMA Ophthalmol. 2016;134(2):167-73. doi:10.1001/jamaophthalmol.2015.4776
• Cursiefen C, Jun AS, editors. Current Treatment Options for Fuchs Endothelial Dystrophy. Springer International Publishing; 2017.
• Cremona FA, Ghosheh FR, Rapuano CJ, Eagle RC, Hammersmith KM, Laibson PR, Ayres BD, Cohen EJ. Keratoconus associated with other corneal dystrophies. Cornea. 2009;28(2):127-35.
• Lechner J, Dash DP, Muszynska D, Hosseini M, Segev F, Geroge S, Frazer DG, Moore JE, Kaye SB, Young T, Simpson DA, Churchill AJ, Héon E, Willoughby CE. Mutational spectrum of the ZEB1 gene in corneal dystrophies supports a genotype-phenotype correlation. IOVS. 2013;54(5):3215-23.
• Ham L, Dapena I, Van Luijk C, Van der Wees J, Melles GR. Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial dystrophy: review of the first 50 consecutive cases. Eye. 2009 Oct;23(10):1990.
• Elhalis H, Azizi B, Jurkunas UV. Fuchs endothelial corneal dystrophy. The ocular surface. 2010 Oct;8(4):173.

Contact

• J. Bradley Randleman MD, Professor of Ophthalmology (Clinical Scholar), randlema@usc.edu
• Sona Shah, MS4, sonashah@usc.edu

Section Editors

• Vivek Patel, MD, Associate Professor of Clinical Ophthalmology, Program Director, vivek.patel@med.usc.edu
• Ben Xu, MD, PhD, Assistant Professor of Clinical Ophthalmology, Assistant Program Director, benjamin.xu@med.usc.edu

Produced by: Monica Chavez, John Daniel and Dr. Vivek Patel