Effect of probe geometry on transsceral diffuse optical spectroscopy

Research output: Contribution to journalArticle


The purpose of this study was to investigate how the geometry of a fiber optic probe affects the transmission and reflection of light through the scleral eye wall. Two geometrical parameters of the fiber probe were investigated: the source-detector distance and the fiber protrusion, i.e. the length of the fiber extending from the flat surface of the fiber probe. For optimization of the fiber optic probe geometry, fluorescence stained choroidal tumor phantoms in ex vivo porcine eyes were measured with both diffuse reflectance- and laser-induced fluorescence spectroscopy. The strength of the fluorescence signal compared to the excitation signal was used as a measure for optimization. Intraocular pressure (IOP) and temperature were monitored to assess the impact of the probe on the eye. For visualizing any possible damage caused by the probe, the scleral surface was imaged with scanning electron microscopy after completion of the spectroscopic measurements. A source-detector distance of 5 mm with zero fiber protrusion was considered optimal in terms of spectroscopic contrast, however, a slight fiber protrusion of 0.5 mm is argued to be advantageous for clinical measurements. The study further indicates that transscleral spectroscopy can be safely performed in human eyes under in vivo conditions, without leading to an unacceptable IOP elevation, a significant rise in tissue temperature, or any visible damage to the scleral surface.


  • Pontus Svenmarker
  • Can Xu
  • Stefan Andersson-Engels
  • Jørgen Krohn
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Atom and Molecular Physics and Optics


  • diffusion, Scattering, fluorescence and luminescence, tissue diagnostics, Spectroscopy, Medical optics instrumentation, visible
Original languageEnglish
Pages (from-to)3058-3071
JournalBiomedical Optics Express
Issue number11
Publication statusPublished - 2011
Publication categoryResearch

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Pontus Svenmarker, 2012, 201 p.

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