Steps to optimize transscleral photocoagulation

  • P.-R. Preuβner
  • O. Schwenn
Laboratory Investigation


•Background: In transscleral photocoagulation, the desired effect is coagulation of parts of the ciliary body or of the peripheral retina. However, the application is often limited by the unwanted effect of coagulation of the sclera. to reduce this effect, the ratio of incident radiation flux to radiation flux transported through the sclera (and able to coagulate the target tissue) should be minimized by the incident beam characteristics.

•Methods: Monte Carlo simulations for the radiation transport problem of multiple scattering in the sclera were used to calculate the ratio of transported to incident radiation for different parameter settings of beam diameters, optical thicknesses of the sclera and beam angles. To verify the theoretical calculations, an simple optical device utilizing a bulb instead of a laser source was constructed and applied to enucleated porcine eyes.

•Results: The theoretical calculations showed that the ratio of incident to transported radiation flux can typically be decreased by a factor of three by increasing the beam radius from 0.35 mm (as used in state-of-the-art laser devices) to 2 mm. This was confirmed by the experiments. Coagulations of the ciliary body or of the peripheral retina were possible with power densities an order of magnitude below the values normally applied with laser sources.

•Conclusion: To improve transscleral photocoagulation, beam diameters should be increased.

Key words

Transscleral cyclophotocoagulation Transscleral retinal coagulation Radiation transport Monte Carlo calculation 


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  1. 1.
    Blasini M, Simmons R, Shields MB (990) Early tissue response to transscleral neodymium:YAG cyclophotocoagulation. Invest Ophthalmol Vis Sci 31:1114–1118Google Scholar
  2. 2.
    Kawahara J, Nakamura R, Wakabayashi Y, Nakano E, Agawa T, Usui M (1990) Effect of transpupillary argon laser cyclophotocoagulation on anterior chamber oxygen tension in rabbit eyes. Jpn J Ophthalmol 34:450–462Google Scholar
  3. 3.
    Maus M, Katz LJ (1990) Choroidal detachment, flat anterior chamber, and hypotony as complications of neodymium:YAG laser cyclophotocoagulation. Ophthalmology 97:69–72Google Scholar
  4. 4.
    Hamada M, Suzuki R, Kurimoto S (1991) Transient complete visual loss during transscleral cyclophotocoagulation. Jpn J Clin Ophthalmol 45:949–951Google Scholar
  5. 5.
    Brooks AMV, Gillies WE (1991) The use of YAG cyclophotocoagulation to lower pressure in advanced glaucoma. Aust NZ J Ophthalmol 19:207–210Google Scholar
  6. 6.
    Heidenkummer HP, Mangouritsas G, Kampik A (1991) Klinische Anwendungen und Ergebnisse der transskleralen Nd:YAG-Zyklophotokoagulation bei therapierefraktärem Glaucom. Klin Monatsbl Augenheilkd 198:174–180Google Scholar
  7. 7.
    Wright MM, Grajewski AL, Feuer WJ (1991) Nd:YAG cyclophotocoagulation: outcome of treatment for uncontrolled glaucoma. Ophthalmic Surg 22:279–283Google Scholar
  8. 8.
    Vogt A (1936) Versuche zur intraokularen Druckherabsetzung mittels Diathermieschädigung des Corpus ciliare (Zyklodiathermiestichelung). Klin Monatsbl Augenheilkd 97:672–673Google Scholar
  9. 9.
    Weekers R, Lavergne G, Watillon M, Gilson M, Legros AM (1961) Effects of photocoagulation of the ciliary body upon ocular tension. Am J Ophthalmol 52:156–163Google Scholar
  10. 10.
    Mc Lean JM, Lincoff HA (1964) Cryosurgery of the ciliary body. Trans Am Ophthalmol Soc 62:385–407Google Scholar
  11. 11.
    de Roetth A Jr (1068) Cryosurgery for the treatment of advanced chronic simple glaucoma. Am J Ophthalmol 66:1034–1041Google Scholar
  12. 12.
    Smith RS, Stein MN (1969) Ocular hazards of transsscleral laser radiation. II. Intraocular injury produced by ruby and neodymium lasers. Am J Ophthalmol 67:100–110Google Scholar
  13. 13.
    Beckman H, Kinoshita A, Rota AN, Sugar HS (1972) Transscleral ruby laser irradiation of the ciliary body in the treatment of intractable glaucoma. Trans Am Acad Ophthalmol Otol 76:423–436Google Scholar
  14. 14.
    Beckman H, Sugar HS (1973) Neodymium laser cyclophotocoagulation. Arch Ophthalmol 90:27–28Google Scholar
  15. 15.
    Donn A (1955) Ultrasonic wave liquifaction of vitreous humor in living rabbits. Arch Ophthalmol 53:215–223Google Scholar
  16. 16.
    Purnell EW, Sokollu A, Torchia R, Taner N (1964) Focal chorioretinitis produced by ultrasound. Invest Ophthalmol 3:657–664Google Scholar
  17. 17.
    Coleman DJ, Lizzi FL, Chang S, Driller J (1981) Applications of therapeutic ultrasound in ophthalmology. In: Kurjak A (ed) Progress in medical ultrasound. Excerpta Medica, Amsterdam, pp 263–270Google Scholar
  18. 18.
    Coleman DJ, Lizzi FL, Driller J, Rosado A, Chang S, Iwamoto T, Rosenthal D (1985) Therapeutic ultrasound in the treatment of glaucoma. I. Experimental model. Ophthalmology 92:339–346Google Scholar
  19. 19.
    Coleman DJ, Lizzi FL, Driller J, Rosado A, Burgess SEP, Torpey JH, Smith ME, Silverman RH, Yablonski ME, Chang S, Rondeau ME (1985) Therapeutic ultrasound in the treatment of glaucoma. II. Clinical applications. Ophthalmology 92:347–353Google Scholar
  20. 20.
    Silverman RH, Vogelsang B, Rondeau MJ, Coleman DJ (1991) Therapeutic ultrasound for the treatment of glaucoma. Am J Ophthalmol 111:327–337Google Scholar
  21. 21.
    Federman JL, Ando F, Schubert HD, Eagle RC (1987) Contact laser for transscleral photocoagulation. Ophthalmic Surg 18:183–184Google Scholar
  22. 22.
    Kwasniewska S, Fankhauser F, Van der Zypen E, Rol P, Henchoz PD, England C (1988) Acute effects following transscleral contact irradiation of the ciliary body and the retina/choroid with the cw Nd:YAG laser. Lasers Light Ophthalmol 2:25–34Google Scholar
  23. 23.
    Rol P, Niederer P, Dürr U, Henchoz PD, Fankhauser F (1990) Experimental investigations on the light scattering properties of the human sclera. Laser Light Ophthalmol 3:201–212Google Scholar
  24. 24.
    Suzuki Y, Araie M, Yumita A, Yamamoto T (1991) Transscleral Nd:YAG laser cyclophotocoagulation versus cyclocryotherapy. Graefe's Arch Clin Exp Ophthalmol 229:33–36Google Scholar
  25. 25.
    Bronstein IN, Semendjajew KA (1986) In: Grosche G, Ziegler V, Ziegler D (eds) Taschenbuch der Mathematik. Harri Deutsch, ThunGoogle Scholar
  26. 26.
    Schröder G (1990) Technische Optik. Vogel, WürzburgGoogle Scholar
  27. 27.
    Krystek M (1993) Optische Strahlung und ihre Messung. In: Niedrig H (ed) Bergmann-Schäfers's Lehrbuch der Experimentalphysik, vol 3, Optik. de Gruyter, BerlinGoogle Scholar
  28. 28.
    Geeraets WJ, Williams RC, Chan G, Ham WT Jr, Guerry D, Schmidt FH (1960) The loss of light energy in retina and choroid. Arch Ophthalmol 64:158–167Google Scholar
  29. 29.
    Allingham RR, Kater AW de, Bellows AR, Hsu J (1990) Probe placement and power levels in contact transscleral neodymium:YAG cyclophotocoagulation. Arch Ophthalmol 108:738–742Google Scholar
  30. 30.
    Schuman JS, Noecker RJ, Puliafito CA, Jacobsson JJ, Shepps GJ, Wang N (1991) Energy levels and probe placement in contact transscleral semiconductor diode laser cyclophotocoagulation in human cadaver eyes. Arch Opthalmol 109:1534–1538Google Scholar

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • P.-R. Preuβner
    • 1
  • O. Schwenn
    • 1
  1. 1.Universitäts-AugenklinikMainzGermany

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