title: Immunohistochemical study of subepithelial haze after phototherapeutic keratectomy.
abstract: OBJECTIVE
  Subepithelial haze is a frequent complication and is often the cause of regression after photorefractive keratectomy (PRK). The lack of understanding of this undesirable complication following PRK is in part due to the limited availability of suitable tissues for pathological studies.
  
  
  METHODS
  We examined the expression of various extracellular components in the cornea of a 46-year-old man who underwent phototherapeutic keratectomy (PTK) to remove a central corneal scar secondary to trauma. The patient subsequently underwent penetrating keratoplasty. A scar-free region containing an area of slight subepithelial haze adjacent to normal cornea was used for immunohistochemical staining with antibodies directed against cytoskeletal proteins, ie, vimentin, desmin and smooth muscle actin, and the extracellular components, laminin, heparan sulfate, keratan sulfate, and collagen types III, IV, V, and VII.
  
  
  RESULTS
  Immunohistochemistry revealed that basal epithelial cells expressed components of basement membrane. The stromal fibroblasts within the haze tissue were labeled by anti-smooth muscle actin antibodies, a characteristic of myofibroblasts, which synthesized and secreted extracellular matrix components that contributed to the formation of the disorganized collagenous matrix and may account for subepithelial haze.
  
  
  CONCLUSIONS
  The expression patterns for the cytoskeletal proteins and extracellular components indicated that the formation of subepithelial haze is a process of tissue remodeling, involving both corneal basal epithelial cells and keratocytes during wound repair.
authors.affiliation: Department of Ophthalmology, National Taiwan University Hospital, Taipei.
authors.forename: Y C
authors.initials: YC
authors.lastname: Lee
authors.forename: I J
authors.initials: IJ
authors.lastname: Wang
authors.forename: F R
authors.initials: FR
authors.lastname: Hu
authors.forename: W W
authors.initials: WW
authors.lastname: Kao
mesh_terms: D003315:Cornea / Q000378:metabolism / Q000601:surgery; D003318:Corneal Opacity / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D015948:Keratoplasty, Penetrating; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D018903:Photorefractive Keratectomy; D011183:Postoperative Complications / Q000378:metabolism*; D014945:Wound Healing
chemical_list: D003598:Cytoskeletal Proteins; D016326:Extracellular Matrix Proteins; D005136:Eye Proteins