title: Second Harmonic Generation Imaging Analysis of Collagen Arrangement in Human Cornea.
abstract: OBJECTIVE
  To describe the horizontal arrangement of human corneal collagen bundles by using second harmonic generation (SHG) imaging.
  
  
  METHODS
  Human corneas were imaged with an inverted two photon excitation fluorescence microscope. The excitation laser (Ti:Sapphire) was tuned to 850 nm. Backscatter signals of SHG were collected through a 425/30-nm bandpass emission filter. Multiple, consecutive, and overlapping image stacks (z-stacks) were acquired to generate three dimensional data sets. ImageJ software was used to analyze the arrangement pattern (irregularity) of collagen bundles at each image plane.
  
  
  RESULTS
  Collagen bundles in the corneal lamellae demonstrated a complex layout merging and splitting within a single lamellar plane. The patterns were significantly different in the superficial and limbal cornea when compared with deep and central regions. Collagen bundles were smaller in the superficial layer and larger in deep lamellae.
  
  
  CONCLUSIONS
  By using SHG imaging, the horizontal arrangement of corneal collagen bundles was elucidated at different depths and focal regions of the human cornea.
authors: Department of Ophthalmology Dongguk University, Ilsan Hospital, Goyang, Kyunggido, South Korea 2Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States.
authors: Choul Yong
authors: CY
authors: Park
authors: Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States.
authors: Jimmy K
authors: JK
authors: Lee
authors: Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States.
authors: Roy S
authors: RS
authors: Chuck
mesh_terms: D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000378:metabolism / Q000473:pathology*; D003952:Diagnostic Imaging; D006801:Humans; D021621:Imaging, Three-Dimensional; D007640:Keratoconus / Q000175:diagnosis* / Q000378:metabolism; D008297:Male; D018613:Microscopy, Confocal; D036641:Microscopy, Fluorescence, Multiphoton; D015203:Reproducibility of Results
chemical_list: D003094:Collagen