May 2007
Volume 48, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2007
Influence of Choroidal Perfusion on Retinal Temperature Increase During Cw Laser Irradiation
Author Affiliations & Notes
  • C. M. Floehr
    Ophthalmology, University of Schleswig Holstein, Campus Kiel, Kiel, Germany
  • J. Kandulla
    Ophthalmology, Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
  • K. Herrmann
    Ophthalmology, Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
  • J. Stalljohann
    Ophthalmology, Medical Laser Center, Luebeck, Germany
  • J. Sandeau
    Ophthalmology, Research Center Claude Delorme, Air Liquide, Jouy-en-Josas, France
  • G. Apiou-Sbirlea
    Ophthalmology, Research Center Claude Delorme, Air Liquide, Jouy-en-Josas, France
  • R. Brinkmann
    Ophthalmology, Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
  • R. Birngruber
    Ophthalmology, Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
  • J. Roider
    Ophthalmology, University of Schleswig Holstein, Campus Kiel, Kiel, Germany
  • Footnotes
    Commercial Relationships C.M. Floehr, None; J. Kandulla, None; K. Herrmann, None; J. Stalljohann, None; J. Sandeau, None; G. Apiou-Sbirlea, None; R. Brinkmann, None; R. Birngruber, None; J. Roider, None.
  • Footnotes
    Support None.
Investigative Ophthalmology & Visual Science May 2007, Vol.48, 2269. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      C. M. Floehr, J. Kandulla, K. Herrmann, J. Stalljohann, J. Sandeau, G. Apiou-Sbirlea, R. Brinkmann, R. Birngruber, J. Roider; Influence of Choroidal Perfusion on Retinal Temperature Increase During Cw Laser Irradiation. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2269.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose:: In retinal laser treatments the therapeutic effect is initiated by a transient temperature increase. The retinal temperature is influenced by differences in pigmentation and transmission of the ocular media. Another factor, important in Transpupillary Thermotherapy (TTT), is choroidal blood flow. Ocular Perfusion acts as a heat dissipating mechanism when heat is externally applied. Individual differences in ocular perfusion can lead to an under- or overdosage of the regarded temperature increase. Aim of this work is to quantify the influence of choroidal perfusion on the retinal temperature increase during cw laser treatments. The experimental obtained data are compared to numerical temperature simulations.

Methods:: The experiments are performed in-vivo on rabbits (Chinchilla Bastard). The retinal temperature increase of less than 12 K is achieved by applying the radiation of a TTT-laser ( = 810 nm) for 1 minute on a 2 mm spot. Optoacoustic techniques are used to determine the temperature increase during the irradiation. For a reduction of the choroidal perfusion, the intraocular pressure (IOP) is increased stepwise from 20 mmHg to 120 mmHg resulting in higher temperature increases. Additionally the rabbit is sacrificed after the last experiment, to eliminate the influence of choroidal blood flow. For an estimation of the perfusion rates, the data are compared to numerical temperature simulations based on two absorbing layers (RPE and choroid) and taking into account choroidal perfusion.

Results:: The results are very much dependent on the individual rabbit. In one rabbit a retinal temperature increase of roughly 5 K was found by applying laser irradiation with a retinal irradiance of 4.7 W/cm2. On the same rabbit an increase of 12 K was found post mortem, which means an increase of 140 %. The temperature data obtained by increasing the IOP are mainly within this range.

Conclusions:: These first measurements demonstrate the high influence of choroidal perfusion on retinal temperature increases during long exposure laser treatments. As the individual perfusion rate can not be quantified before a treatment, a dosimetry control, based on an online determination of retinal temperature increases, is necessary to enhance the safety of retinal cw laser treatments.

Keywords: blood supply • laser • retina 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×