Swept-source Fourier-domain optical coherence tomography (SS-OCT) yields better corneal thickness measurements than the Scheimpflug camera for patients with Fuch's endothelial corneal dystrophy (FECD) or an endothelial transplant, a recent study found. Researchers from Spain compared repeatability and reproducibility coefficients of the two imaging modalities between 36 control eyes, 35 FECD eyes, 30 FECD eyes with corneal edema, 25 eyes after Descemet stripping automated endothelial keratoplasty and 29 eyes that had Descemet’s membrane endothelial keratoplasty.
While both systems showed high corneal thickness reproducibility and repeatability, SS-OCT results were higher and more precise across patient groups—often significantly so. “The possible reasons for the better repeatability could be related to the higher scanning speed, which may overcome the eye motion-related artifacts, and its higher resolution, which may refine the detection of the anterior and posterior corneal surfaces,” the study said. “Probably because OCT offers far superior morphological detail, it provides more accurate measurements.”
However, in addition to a variety of discrepancies between the two devices, researchers also noted that SS-OCT results underestimated all variables. “The measurement values from these two systems are not directly interchangeable in clinical practice but SS-OCT and the Scheimpflug camera are reliable pachymetric tools that can yield highly repeatable values between examinations in virgin eyes with FECD or those treated with endothelial keratoplasty,” the study concluded. “Additionally, OCT technology currently offers the sublayer pachymetry option of corneal epithelium imaging, which in abnormal corneas with endothelial disease, may offer an additional clinical investigative piece of information.”
|Arnalich-Montiel F, Ortiz-Toquero S, Auladell C, Couceiro A. Accuracy of corneal thickness by swept-source optical coherence tomography and Scheimpflug camera in virgin and treated Fuchs endothelial dystrophy. Cornea. 2018;37(6):727-33.|