High-Resolution Anterior Segment Optical Coherence Tomography and in vivo Confocal Microscopy in the Evaluation of Corneal Dystrophies

Abstract

 

Purpose

 

To describe the findings observed with high-resolution anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM) in patients with corneal dystrophies.

 

Methods

 

Five patients with common corneal dystrophies seen in clinical practice were evaluated with a high-resolution spectral-domain AS-OCT (Heidelberg Engineering, Germany) and IVCM using the Heidelberg Retina Tomograph 3 Rostock Cornea Module (Heidelberg Engineering, Germany). A high-speed swept-source OCT (SS-OCT) prototype was also used to reconstruct the three-dimensional structures of the cornea.

 

Results

 

Patients included in this study had the following corneal dystrophies: epithelial basement membrane dystrophy (EBMD), granular cornea dystrophy (GCD), lattice cornea dystrophy (LCD), posterior polymorphous corneal dystrophy (PPMD) and Fuchs’ endothelial dystrophy (FD). AS-OCT and IVCM provided precise information about the pathology in the different layers of the cornea in all patients. There was a significant correlation between the two imaging modalities. In EBMD, we identified an abnormal epithelial basement membrane protruding into the corneal epithelium and clusters of epithelial cells in the tear film. In GCD, the majority of opacities were visualized in the anterior two-thirds of the corneal stroma although rare opacities were seen in the posterior stroma. In LCD, hyperreflective linear and branching structures with poorly demarcated margins were noted in the stroma. In PPMD, a variety of vesicular and linear abnormalities could be identified at the level of the endothelium. In FD, Descemet's membrane was thickened with round hyporeflective structures (guttae) at level of the endothelium,with fibrosis and activated keratocytes seen in the stroma.

 

Conclusions

 

AS-OCT and IVCM are non-invasive, high-resolution imaging modalities useful in the visualization of the corneal microstructural changes related to corneal dystrophies. These new imaging technologies are rapidly becoming widely used instruments for both research and patient care, and may be useful in elucidating the pathogenesis and natural course of corneal dystrophies.

 

 

Patient with EBMD evaluated with in vivo confocal microscopy (IVCM) and anterior segment OCT (AS-OCT).

 

 

Patient with granular dystrophy evaluated with in vivo confocal microscopy (IVCM) and anterior segment OCT (AS-OCT)

 

Keywords: 479 cornea: clinical science • 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 596 microscopy: confocal/tunneling