J.ophthalmol.(Ukraine).2017;6:56-71.

https://doi.org/10.31288/oftalmolzh201765671

Comparing ultrastructural changes in the rabbit chorioretinal complex after 577-nm and 532-nm laser photocoagulation

S.A. Fedchenko, Ophthalmologist, Post-grad Student, O.S. Zadorozhnyy,  Cand Sc (Med),  N.I. Molchaniuk, Cand Sc (Biol), Sen Res Fellow, A.R. Korol, Dr Sc (Med)

Filatov Institute of Eye Disease and Tissue Therapy

Odessa, Ukraine

E-mail: laserfilatova@gmail.com             

Background: There is no unanimously adopted approach to titrating laser parameters in subthreshold retinal laser photocoagulation without ophthalmoscopically visible fundus changes.

Purpose: To compare the ultrastructural changes in the rabbit chorioretinal complex after various modes of 577-nm and 532-nm laser photocoagulation.

Materials and Methods: Ten rabbits (20 eyes) were involved in the experimental study. Eight (10 eyes) of them underwent different modes of 577-nm or 532-nm laser photocoagulation, and were euthanized at postlaser days 1 (4 rabbits) or 14 (4 rabbits). Ultra-thin sections of their ocular tissue specimens were subjected to electron microscopy and assessed for the state of their choriocapillaries, RPE and photoreceptor cells. In addition, 2 intact rabbits (4 eyes) were used as controls for comparison.

Results: 577-nm or 532-nm conventional RLPC resulted in damage to RPE cells, all photoreceptor compartments and choriocapillaries; 577-nm or 532-nm selective RLPC resulted in damage to RPE cells and photoreceptor outer and inner segments, and 577-nm micropulse RLPC with the power setting adjusted to 50% threshold resulted in damage mostly to apical aspects of RPE cells and photoreceptor outer segments.

Conclusion: 577-nm micropulse RLPC with the power setting adjusted to 50% threshold is a more photoreceptor- and choriocapillaris-sparing approach compared to 577-nm or 532-nm conventional and selective RLPC, and can be used in clinical practice as a laser treatment approach with the least invasive effect on the chorioretinal complex.

Keywords: chorioretinal complex, laser radiation, ultrastructural changes      


References

  1. Pasyechnikova NV, Naumenko VA, Katsan SV. [Efficacy of selective laser photocoagulation of the macular region for age-related maculopathy depending on the structure and function of the region]. Oftalmol Zh. 2006;2:4-9. Russian
  2. Roider J, Brinkmann R, Wirbelauer C, et al. Subthreshold (retinal pigment epithelium) photocoagulation in macular diseases: a pilot study. Br J Ophthalmol. 2000;84(1):40–7
  3. Youssef PN, Sheibani N, Albert DM. Retinal light toxicity. Eye (Lond). 2011 Jan; 25(1): 1–14
  4. Gatsu MV, Gordeyeva MV. [Modern concepts of laser treatment of soft macular drusen]. Oftalmologicheskie vedomosti. 2014;7(1):72-81 Russian
  5. Romanova TA. [The ultrastructural changes of the choroid and retinal pigment epithelium of rabbits after exposure to subthreshold lasers with 532nm, 577 nm, and 810 nm wavelengths using millipulse and micropulse laser modes]. Kharkivska khirurgichna shkola. 2014;4:74-9. Russian
  6. Maia A. A New Treatment for Chronic Central Serous Retinopathy. Retina Today. 2010 Jan-Feb (1):1-3.
  7. Scholz P, Ersoy L, Boon CJ, Fauser S. Subthreshold Micropulse Laser (577 nm) Treatment in Chronic Central Serous Chorioretinopathy. Ophthalmologica. 2015;234(4):189-94
  8. Fedchenko SA, Zadorozhnyy OS, Molchaniuk NI, Korol AR. [Ultrastructural changes in the rabbit chorioretinal complex following 577-nm laser photocoagulation]. Oftalmol Zh. 2017;4:51-5. Russian
  9. Semenyuk V. Thermal interaction of multi-pulse laser beam with eye tissue during retinal photocoagulation: Analytical approach. Int J Heat Mass Transf. 2017;112(1):480-488
  10. Pasyechnikova NV. [Theoretical and clinical study of the efficacy of laser treatment for retinal disorders] [Dr. Sc. (Med) dissertation]. Odesa: Filatov Institute of Eye Disease; 2003. 312 p. Russian
  11. Roider J, Michaud NA, Flotte TJ, Birngruber R. Response of the retinal pigment epithelium to selective photocoagulation. Arch Ophthalmol. 1992 Dec;110(12):1786-92.
  12. Roider  J, Michaud  N, Flotte  T, Birngruber  R. Histologie von Netzhautl?sionen nach kontinuierlicher Bestrahlung und nach selektiver Mikrokoagulation des retinalen Pigmentepithels. Ophthalmologe. 1993 Jun;90(3):274–8
  13. Pasyechnikova NV, Ivanytska OV, Katsan SV. [Optimizing the management of patients with macular drusen in age-related maculopathy]. Naukovyi visnyk Uzhgorods’kogo universitetu. 2004;22:75-78. Ukrainian