Imaging Microscopic Features of Keratoconic Corneal Morphology

Abstract

Purpose:To search for gold-standard histology indicators using alternative imaging modalities in keratoconic corneas.Methods:Prospective observational case–control study. Fourteen keratoconic corneas and 20 normal corneas (10 in vivo healthy subjects and 10 ex vivo donor corneas) were examined. Images of corneas were taken by spectral domain optical coherence tomography (SD-OCT) and in vivo confocal microscopy (IVCM) before keratoplasty. The same removed corneal buttons were imaged after keratoplasty with full-field optical coherence microscopy (FFOCM) and then fixed and sent for histology. Controls consisted of normal subjects imaged in vivo with IVCM and donor corneas imaged ex vivo with FFOCM. Corneal structural changes related to pathology were noted with each imaging modality. Cell density was quantified by manual cell counting.Results:Keratoconus indicators (ie, epithelial thinning/thickening, cell shape changes, ferritin deposits, basement membrane anomalies, Bowman layer thinning, ruptures, interruptions, scarring, stromal modifications, and appearance of Vogt striae) were generally visible with all modalities. Additional features could be seen with FFOCM in comparison with gold-standard histology, particularly in the Bowman layer region, whereas the combination of SD-OCT plus IVCM detected 76% of those features detected in histology. Three-dimensional FFOCM imaging aided interpretation of two-dimensional IVCM and SD-OCT data. Basal epithelial cell and keratocyte densities were significantly lower in patients with keratoconus than those in normals (P < 0.0001).Conclusions:Structural and cellular assessment of the keratoconic cornea by means of either in vivo SD-OCT combined with IVCM or ex vivo FFOCM in both cross-sectional and en face views can detect as many keratoconus indicators as gold-standard histology.

Histological and microRNA Signatures of Corneal Epithelium in Keratoconus

“…However, in vivo confocal images showed abnormal features in every layer of the cornea, including abnormal epithelial and stromal keratocytes. 8 Microscopic features of keratoconic corneas indicated irregular arrangement in basal epithelial cells, 4,8 reduction in basal epithelial cell and keratocyte densities, 4,13 and epithelial apoptosis along with Histological and microRNA Signatures in Keratoconus/Wang et al corneal epithelium thinning. 9 Likewise in our study, the keratoconic corneal epithelial cells were loosely arranged ( Figure 1A) and significantly fewer in number compared to normal corneal epithelia ( Figure 1B).…”

Highly concentrated collagen solutions leading to transparent scaffolds of controlled three-dimensional organizations for corneal epithelial cell colonization

“…After 14-days of culture, the cell sheet area grown on the scaffolds and on the AM were imaged non-invasively with full-field optical coherence microscopy (FFOCM, LLTech, France 40,41,42,43,44,45 ) to determine the number of cell layers grown on the carriers.…”

Imaging the Cornea, Anterior Chamber, and Lens in Corneal and Refractive Surgery

“…They also showed that the posterior surface measurement was more reliable than with Scheimpflug technology [11]. New methods such as corneal OCT and topographic mapping of EP and BL have been proposed for early detection of keratoconus [12][13][14][15]. However, this requires high-resolution OCT technology in order to resolve EP and BL with sufficient precision.…”