Selective transscleral cyclophotocoagulation: mathematical modeling for evaluating the efficacy-safety balance in neovascular glaucoma

Authors

DOI:

https://doi.org/10.31288/Ukr.j.ophthalmol.20264413

Keywords:

neovascular glaucoma, transscleral cyclophotocoagulation, mathematical modeling, temperature, Thermal Selectivity Index, intraocular pressure

Abstract

Purpose. To quantitatively evaluate the efficacy-safety balance of transscleral cyclophotocoagulation (TSCPC) through a mathematical modeling-based analysis of thermal tissue response in the ciliary body, and to determine the laser exposure parameters for achieving a selective coagulation effect in neovascular glaucoma (NVG).

Material and Methods. A model of heat transfer in the ciliary body was developed using the Pennes bioheat transfer equation. Continuous Wave (CW) TSCPC and MicroPulse TSCPC at 1 W and 2W for a single 2-s application and a series of 2-s applications were subjected to analysis. The following parameters were determined: maximum temperature (Tmax), time to reach 50 °C (t50), time in the temperature range 50–60 °C (t50-60), and time in the temperature range above 60 °C (t(>60)). Integral thermal indices including the Therapeutic Exposure Index (TEI), Destructive Exposure Index (DEI), and Thermal Selectivity Index (TSI), and Safety Margin were calculated.

Results. A single 2-s CW-TSCPC application at 1 W enabled achieving the coagulation temperature threshold (Tmax = 50.8 °C; t50 = 1.44 s) without a transition to the destructive temperature range (> 60 °C), whereas that at 2 W was accompanied by tissue overheating (Tmax = 61.8 °C; t50 = 0.4 s). A series of 2-s CW laser applications at 1 W enabled accumulation of the heat dose within the therapeutic window (t50–60 = 17.1 s; DEI = 0), whereas that at 2 W resulted in large t(>60) values (t(>60) = 39.7 s; DEI = 0.67). MicroPulse TSCPC did not result in reaching the coagulation threshold (Tmax ≤ 49 °C). The integral indices confirmed the optimal efficacy–safety balance for a CW-TSCPC application at 1 W.

Conclusion. The 60 °C temperature threshold determines the transition from coagulative to destructive tissue injury. Therefore, CW-TSCPC at 1 W provides an optimal efficacy-safety balance due to a selective coagulative effect, and can be considered a pathophysiologically justified strategy for optimizing TSCPC parameters in NVG.

Author Biographies

  • O. V. Guzun, Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine

    Olga V. Guzun, Cand Sc (Med), Senior Researcher, SI “The Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine”, Odesa, Ukraine

  • O. S. Zadorozhnyy, Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine

    Oleg S. Zadorozhnyy, Dr Sc (Med), Senior Researcher and Deputy Director for Scientific Work, SI “The Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine”, Odesa, Ukraine

  • P. I. Osadchuk, Odesa National University of Technology

    Petr Osadchuk, Dr Sc (Engineering), Prof. and Chair, Department for Electromechanics and Mechatronics, Institute of Automation and Robotics, Odesa National University of Technology, Odesa, Ukraine

  • V. V. Vychuzhanin, Odesа Polytechnic National University

    Vladimir Vychuzhanin, Dr Sc (Engineering), Prof. and Chair, Department of Information Technologies, Odesa Polytechnic National University, Odesa, Ukraine

  • A. D. Khomenko, Odesa National University of Technology

    Andrii Khomenko, Lecturer, Department for Electromechanics and Mechatronics, Institute of Automation and Robotics, Odesa National University of Technology, Odesa, Ukraine

  • A. R. Korol, Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine

    Andrii Korol, Dr Sc (Med), Prof., Senior Researcher and Deputy Director for Innovation and External Relations, SI “The Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine”, Odesa, Ukraine; 

References

Schlote T, Derse M, Rassmann K, Nicaeus T, Dietz K, Thiel HJ. Efficacy and safety of contact transscleral diode laser cyclophotocoagulation for advanced glaucoma. J Glaucoma. 2001;10(4):294-301. https://doi.org/10.1097/00061198-200108000-00006

Pastor SA, Singh K, Lee DA, Juzych MS, Lin SC, Netland PA, et al. Cyclophotocoagulation: a report by the American Academy of Ophthalmology. Ophthalmology. 2001;108(11):2130-2138. https://doi.org/10.1016/S0161-6420(01)00889-2

Aquino MCD, Barton K, Tan AMWT, Sng CCA, Li X, Loon SC, et al. Micropulse versus continuous wave transscleral diode cyclophotocoagulation in refractory glaucoma. Clin Exp Ophthalmol. 2015;43(1):40-46. https://doi.org/10.1111/ceo.12360

Niemz MH. Laser-Tissue Interactions: Fundamentals and Applications. 3rd ed. Berlin: Springer; 2007. https://doi.org/10.1007/978-3-540-73412-5

Brinkmann R, Hüttmann G, Rögener J, Roider J, Birngruber R. Origin of retinal pigment epithelium cell damage by pulsed laser irradiance in the nanosecond to microsecond time regimen. Lasers Surg Med. 2000;27(5):451-464. https://doi.org/10.1002/1096-9101(2000)27:5<451::AID-LSM1006>3.0.CO;2-1

van Rhoon GC, Samaras T, Yarmolenko PS, Dewhirst MW, Neufeld E, Kuster N. CEM43°C thermal dose thresholds: a potential guide for magnetic resonance radiofrequency exposure levels? Eur Radiol. 2013;23(8):2215-2227. https://doi.org/10.1007/s00330-013-2825-y

Sapareto SA, Dewey WC. Thermal dose determination in cancer therapy. Int J Radiat Oncol Biol Phys. 1984;10(6):787-800. https://doi.org/10.1016/0360-3016(84)90379-1

Pennes HH. Analysis of tissue and arterial blood temperatures in the resting human forearm. J Appl Physiol. 1948;1(2):93-122. https://doi.org/10.1152/jappl.1948.1.2.93

Jacques SL. Optical properties of biological tissues: a review. Phys Med Biol. 2013;58(11):R37-R61. https://doi.org/10.1088/0031-9155/58/11/R37

Welch AJ, van Gemert MJC. Optical-Thermal Response of Laser-Irradiated Tissue. 2nd ed. Dordrecht: Springer; 2011. https://doi.org/10.1007/978-90-481-8831-4

Duck FA. Physical Properties of Tissue: A Comprehensive Reference Book. London: Academic Press; 1990. 346 p. ISBN: 9780122228001. https://doi.org/10.1016/B978-0-12-222800-1.50009-7

Cicekli U. Computational model for heat transfer in the human eye using the finite element method [master's thesis]. Baton Rouge (LA): Louisiana State University; 2003. https://doi.org/10.31390/gradschool_theses.2762

Cooper TE, Trezek GJ. Correlation of thermal properties of some human tissues with water content. Aerosp Med. 1972;43(1):24-27.

Birngruber R, Hillenkamp F, Gabel VP. Theoretical investigations of laser thermal retinal injury. Health Phys. 1991;60(4):505-515.

Grippo TM, LaMarche K, Davreux AM, Stauffer J, Stacey S, Arnold K. Thermal tissue modeling of the ciliary body with continuous-wave transscleral cyclophotocoagulation and transscleral laser therapy using MicroPulse technology. Transl Vis Sci Technol. 2025;14(11):32. https://doi.org/10.1167/tvst.14.11.32

Guzun OV, Zadorozhnyy OS, Chechin PP, Artemov OV, Chargui W, Korol AR. Comparing histopathological effects of the neodymium and diode laser transscleral cyclophotocoagulation: an experimental study. Ukr. j. ophthalmol. 2024;(5):32-7. https://ua.ozhurnal.com/index.php/files/article/view/197

Guzun OV, Zadorozhnyy OS, Chechin PP, Artemov OV, Chargui W, Korol AR. Histopathological changes in rabbit eyes after transscleral diode cyclophotocoagulation. Odesa Med J. 2024;4(189):13-18. https://doi.org/10.32782/2226-2008-2024-4-2

Zadorozhnyy OS, Guzun OV, Kustrin TB, Korol AR, Naumenko VA, Pasechnikova NV. Parameters of heat exchange in the eyes of patients with terminal neovascular glaucoma and proliferative diabetic retinopathy. J Ophthalmol (Ukraine). 2020;(1):10-13. https://doi.org/10.31288/oftalmolzh202011013

Sari C, Alagoz N, Omeroglu A, Cakir I, Pasaoglu I, Altan C, et al. Long-term results of transscleral diode laser cyclophotocoagulation in glaucoma: a real-life study. J Glaucoma. 2024;33(6):437-443. https://doi.org/10.1097/IJG.0000000000002346

Cheng Y, Shen Y, Gao Y, Wen Y, Lv Z, Wang E, et al. Theoretical and experimental analysis of the effect of vaporization heat on the interaction between laser and biological tissue. Appl Sci (Basel). 2024;14(10):4333. https://doi.org/10.3390/app14104333

Thananjayan P, Arrutselvi M, Natarajan S. Non-invasive characterization of tumors using Bayesian inference and Virtual Element Method. Comput Methods Programs Biomed. 2026 Jun;280:109319. https://doi.org/10.1016/j.cmpb.2026.109319

Bloom PA, Tsai JC, Sharma K, Miller MH, Rice NS, Hitchings RA, Khaw PT. "Cyclodiode". Trans-scleral diode laser cyclophotocoagulation in the treatment of advanced refractory glaucoma. Ophthalmology. 1997 Sep;104(9):1508-19; discussion 1519-20. https://doi.org/10.1016/S0161-6420(97)30109-2

Elhusseiny AM, et al. Primary slow-coagulation transscleral cyclophotocoagulation laser treatment for medically recalcitrant neovascular glaucoma. Br J Ophthalmol. 2023;107(5):671-676. https://doi.org/10.1136/bjophthalmol-2021-319757

Ezzouhairi SM, Naciri L, Mba T, Jomaa R. A new approach for CW-TSCPC to improve its safety and efficacy in glaucoma treatment. J Fr Ophtalmol. 2022;45(1):93-103. https://doi.org/10.1016/j.jfo.2021.06.006

Kuchar S, Moster MR, Reamer CB, Waisbourd M. Treatment outcomes of micropulse transscleral cyclophotocoagulation in advanced glaucoma. Ophthalmol Glaucoma. 2020;3(4):272-278. https://doi.org/10.1016/j.ogla.2020.01.003

Jun F, Ling Q, Yunhe S, Xinbo G, Yingzhe Z, Yu C, et al. Efficacy and safety of micropulse transscleral cyclophotocoagulation in refractory glaucoma: a prospective multicenter observational study. Chin J Exp Ophthalmol. 2024;42(6):527-531. https://doi.org/10.3760/cma.j.cn115989-20231201-00192

Hwang, Y.H., Lee, S., Kim, M. et al. Comparison of treatment outcomes between slow coagulation transscleral cyclophotocoagulation and micropulse transscleral laser treatment. Sci Rep 14, 23944 (2024). https://doi.org/10.1038/s41598-024-75246-y

Szabó Á, Árpádffy-Lovas T, Hagyó K, Cseke I, Vámosi P, Tóth-Molnár E. The effect of cumulative energy in repeated subliminal transscleral cyclophotocoagulation: a retrospective study. BMC Ophthalmol. 2024 Jun 3;24(1):233. https://doi.org/10.1186/s12886-024-03505-7

Ademaj A, Veltsista DP, Ghadjar P, Marder D, Oberacker E, Ott OJ, et al. Clinical evidence for thermometric parameters to guide hyperthermia treatment. Cancers (Basel). 2022;14(3):625. https://doi.org/10.3390/cancers14030625

Zhang J, Chauhan S. Neural network methodology for real-time modelling of bio-heat transfer during thermo-therapeutic applications. Artif Intell Med. 2019;101:101728. https://doi.org/10.1016/j.artmed.2019.101728

Saigre T, Chabannes V, Prud'homme C, Szopos M. Mathematical modeling and simulation of coupled aqueous humor flow and temperature distribution in a realistic 3D human eye geometry. Int J Numer Method Biomed Eng. 2026;42(1):e70132. https://doi.org/10.1002/cnm.70132

Downloads

Published

2026-08-31

Issue

No. 4 (2026): Ukrainian Journal of Ophthalmology

Section

Clinical Ophthalmology

License

Copyright (c) 2026 Guzun O.V., Zadorozhnyy O. S., Osadchuk P. I., Vychuzhanin V. V., Khomenko A. D., Korol A. R.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

This work is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) that allows users to read, download, copy, distribute, print, search, or link to the full texts of the articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author as long as they cite the source.

COPYRIGHT NOTICE

Authors who publish in this journal agree to the following terms:

  1. Authors hold copyright immediately after publication of their works and retain publishing rights without any restrictions.
  2. The copyright commencement date complies the publication date of the issue, where the article is included in.

DEPOSIT POLICY

  1. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) during the editorial process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.
  2. Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work with an acknowledgement of its initial publication in this journal.
  3. Post-print (post-refereeing manuscript version) and publisher's PDF-version self-archiving is allowed.
  4. Archiving the pre-print (pre-refereeing manuscript version) not allowed.

How to Cite

1.
Selective transscleral cyclophotocoagulation: mathematical modeling for evaluating the efficacy-safety balance in neovascular glaucoma. Ukr. j. ophthalmol. [Internet]. 2026 Aug. 31 [cited 2026 Sep. 1];(4):4-13. Available from: https://ua.ozhurnal.com/index.php/files/article/view/986

Most read articles by the same author(s)

1 2 > >>