title: Polarimetric Interferometry for Assessment of Corneal Stromal Lamellae Orientation.
abstract: OBJECTIVE
  To analyze corneal stromal lamellae orientation in normal subjects and patients with various corneal conditions using a polarimetric interferometer.
  
  
  METHODS
  Thirty-two healthy control subjects (59 eyes) and 16 patients (22 eyes) with corneal conditions or postkeratoplasty were included in the study. All patients were imaged using the interferometer and slit lamp photography. The interferometer produces an orthogonal cross-like image of stromal lamellae by illuminating the cornea in phase-light polarization angle. Corneal haze was graded on a scale from 0 to 4. Interferometer cross-like images were graded on a scale from 0 to 5 by a masked observer. Keratometry, corneal central pachymetry, and optical densitometry were obtained with Scheimpflug corneal tomography.
  
  
  RESULTS
  The cross-like image was observed in 31 of 32 healthy control subjects (58 of 59 eyes) and in 13 of 16 patients (19 of 22 eyes). The image was not detectable in 3 patients, 1 with total corneal neovascularization and scarring, 1 with central leukoma, and 1 with failed deep lamellar keratoplasty. Corneal haze was the main factor obscuring the cross-like image (P < 0.05). Clarity of the images was influenced by older age, steeper keratometry, higher pachymetry, and optical density (P < 0.05). There was no correlation between the orientation of the keratometric axes and the orientation of the 2 arms of the cross-like image (P > 0.05).
  
  
  CONCLUSIONS
  Corneal stromal lamellae orientation can be efficiently assessed and displayed as a cross-like image by the polarimetric interferometer. Stromal lamellae orientation imaging may have potential implications in corneal diagnostics and surgery.
authors: *Department of Ophthalmology, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy; †Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada; ‡Department of Ophthalmology, Villa Igea Hospital, Forlì, Italy; §Department of Ophthalmology, Rabin Medical Center, Petach Tikva, Israel; ¶Department of Ophthalmology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; ‖Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada; **Division of Ophthalmology, Department of Surgery, Credit Valley Hospital, Trillium Health Partners, Mississauga, Ontario, Canada; and ††Phronema S.r.l., Taranto, Italy.
authors: Alfonso
authors: A
authors: Iovieno
authors: Sonia N
authors: SN
authors: Yeung
authors: Yoav
authors: Y
authors: Nahum
authors: Joshua
authors: J
authors: Teichman
authors: Eugenio
authors: E
authors: Lipari
authors: Massimo
authors: M
authors: Busin
authors: Luigi
authors: L
authors: Fontana
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003316:Corneal Diseases / Q000175:diagnosis*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000033:anatomy & histology* / Q000473:pathology*; D019781:Corneal Topography; D003720:Densitometry; D005260:Female; D024022:Fibrillar Collagens / Q000032:analysis*; D006801:Humans; D007368:Interferometry / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D057109:Scanning Laser Polarimetry; D066167:Slit Lamp
chemical_list: D024022:Fibrillar Collagens