Corneal tomographic features of postrefractive surgery ectasia. Issue 2 (24th September 2018)

• Record Type: Journal Article
• Authors: Khamar, Pooja; Dalal, Ritika; Chandapura, Rachana; Francis, Mathew; Shetty, Rohit; Nelson, Everette J. R.; Nuijts, Rudy M. M. A.; Sinha Roy, Abhijit
• Is Part Of: Journal of biophotonics. Volume 12:Issue 2(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-24
• Subjects: ectasia -- cornea -- SMILE -- LASIK -- tomography -- OCT -- Bowman's layer; Photonics -- Periodicals; Optical materials -- Periodicals; Optics -- Periodicals; Medical instruments and apparatus -- Periodicals; 621.3605
• DOI: 10.1002/jbio.201800253
• Languages: English
• ISSNs: 1864-063X

Abstract

Abstract : The purpose of this study was to evaluate the tomographic features of postrefractive surgery eyes. This was a retrospective evaluation of clinical data. Three patients with post‐LASIK (laser‐assisted in situ keratomileusis) and two patients with post‐SMILE (small incision lenticule extraction) ectasia were imaged with Scheimpflug imaging (SI, Pentacam) and optical coherence tomography (OCT, RTVue). Curvature and wavefront aberrations of the air‐epithelium interface (A‐E) and epithelium‐Bowman's layer interface (E‐B) were derived. OCT of normal and keratoconic eyes from an earlier study were compared with the data of the ectasia eyes. Curvature and aberrometry of the A‐E interfaces were statistically similar between SI and OCT. However, OCT revealed a steeper and more aberrated E‐B interface than A‐E though correlation between them was inferior to the correlation for keratoconic eyes. Furthermore, the magnitude of differences between the A‐E and E‐B interfaces was greater in the ectasia eyes than the keratoconic eyes. OCT could possibly assist better in selecting appropriate treatment plan for postrefractive surgery ectasia eyes than conventional tomographers. Abstract : We present novel findings about postrefractive surgery ectasia corneas. High‐resolution optical coherence tomography was used to reconstruct the anterior corneal surface (A‐E) and epithelium‐Bowman's layer (E‐B) interface. The E‐B had a greater degree of irregularity than the A‐E surface. On comparison with the E‐B interface of keratoconus eyes having similar curvature, the degree of irregularity was greater. Thus, ectasia corneas may have global weakening of the cornea compared to focal degradation in keratoconus.