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Fundus autofluorescence and Fourier-domain optical coherence tomography imaging of 10 and 20 millisecond Pascal retinal photocoagulation treatment
  1. M M K Muqit1,
  2. J C B Gray1,
  3. G R Marcellino2,
  4. D B Henson1,
  5. L B Young1,
  6. S J Charles1,
  7. G S Turner1,
  8. P E Stanga1
  1. 1
    Manchester Royal Eye Hospital, Oxford Road, Manchester, UK
  2. 2
    OptiMedica Corporation, Santa Clara, California, USA
  1. Mr P E Stanga, Consultant Ophthalmologist and Vitreoretinal Surgeon, Manchester Royal Eye Hospital, Oxford Road, Manchester M13 9WH, UK; retinaspecialist{at}


Aim: To report the evolution of pattern scanning laser (Pascal) photocoagulation burns in the treatment of diabetic retinopathy, using Fourier-domain optical coherence tomography (FD-OCT) and fundus autofluorescence (AF), and to evaluate these characteristics with clinically visible alterations in outer retina (OR) and retinal pigment epithelium (RPE).

Methods: Standard red-free and colour fundus photography (FP), FD-OCT, and fundus camera-based AF were performed in 17 eyes of 11 patients following macular and panretinal photocoagulation (PRP).

Results: One hour following Pascal application, visibility of threshold burns on FP was incomplete. AF enabled visualisation of complete treatment arrays at 1 h, with hypoautofluorescence at sites of each laser burn. AF signals accurately correlated with localised increased optical reflectivity within the outer retina on FD-OCT. AF signals became hyperautofluorescent at 1 week, and corresponded on FD-OCT to defects at the junction of the inner and outer segments of the photoreceptors (JI/OSP) and upper surface of RPE. A 10 ms macular laser pulse produced a localised defect at the level of JI/OSP and RPE. Macular and 20 ms PRP burns did not enlarge at 1 year’s and 18 months’ follow-up respectively.

Conclusions: We report the in vivo spatial localisation and clinical correlation of medium-pulse Pascal photocoagulation burns within outer retina and RPE, using high-resolution FD-OCT and AF. Ophthalmoscopically invisible and threshold Pascal burns may be accurately localised and mapped by AF and FD-OCT, with monitoring over time.

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  • Funding: This study was sponsored/funded by OptiMedica Corporation.

  • Competing interests: GRM is employed by the OptiMedica Corporation and has a proprietary interest in the Pascal Photocoagulator.

  • Patient consent: Obtained.