title: Imaging retinal pigment epithelial proliferation secondary to PASCAL photocoagulation in vivo by polarization-sensitive optical coherence tomography.
abstract: OBJECTIVE
  To image the retinal pigment epithelium (RPE) after macular laser and to monitor healing responses over time in vivo in patients with diabetic maculopathy using polarization-sensitive optical coherence tomography (OCT).
  
  
  METHODS
  Prospective, nonrandomized clinical trial.
  
  
  METHODS
  In this single-center trial (Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria), 13 patients (13 eyes) underwent grid photocoagulation for diabetic maculopathy. Retinal healing processes were continuously followed over the course of 3 months. A polarization-sensitive OCT prototype was used, allowing detection and measurement of the RPE changes based on their specific polarization-scrambling qualities.
  
  
  RESULTS
  After 1 day, the intraretinal photocoagulation lesions were sharply demarcated, whereas RPE changes were rather subtle. At 1 week, all lesions exhibited traction of the inner retinal layers toward the RPE and loss of photoreceptor cells. In tissue-sensitive polarization-sensitive OCT imaging, polarization-scrambling columns were found at the level of the RPE. During follow-up, different healing responses were seen in the polarization-scrambling RPE layer, ranging from hyperproliferation to focal atrophy.
  
  
  CONCLUSIONS
  Because of the properties of the polarization state of backscattered light, polarization-sensitive OCT revealed specific morphologic changes in the RPE and outer retinal layers secondary to retinal laser treatment undetectable with intensity-based spectral-domain OCT. The increase in polarization-scrambling tissue over the course of 3 months indicates a more intense healing reaction and proliferation of RPE cells than previously characterized in rodent studies.
authors.affiliation: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors.forename: Jan
authors.initials: J
authors.lastname: Lammer
authors.forename: Matthias
authors.initials: M
authors.lastname: Bolz
authors.forename: Bernhard
authors.initials: B
authors.lastname: Baumann
authors.forename: Michael
authors.initials: M
authors.lastname: Pircher
authors.forename: Erich
authors.initials: E
authors.lastname: Götzinger
authors.forename: Georgios
authors.initials: G
authors.lastname: Mylonas
authors.forename: Christoph K
authors.initials: CK
authors.lastname: Hitzenberger
authors.forename: Ursula
authors.initials: U
authors.lastname: Schmidt-Erfurth
mesh_terms: D049109:Cell Proliferation; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017075:Laser Coagulation; D008269:Macular Edema / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012160:Retina / Q000503:physiopathology; D055213:Retinal Pigment Epithelium / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000295:instrumentation*; D014945:Wound Healing / Q000502:physiology