Innovative Technologies in Experimental Corneal Surgery ex vivo

The aim of the study was to assess the feasibility and outcomes of surgical interventions on the cornea in ex vivo experiments using the Femto Visum femtosecond laser system (Optosystems Ltd., Russia).

Materials and Methods. This collective study was conducted by the S. Fyodorov Eye Microsurgery Federal State Institution together with the Scientific-Experimental Production “Eye Microsurgery” Ltd. We have developed a technology for surgical intervention on the cornea with the polymeric intrastromal ring implantation aimed to prevent post-keratoplastic astigmatism. To correct defects of the iris, an original colored gel implant was inserted into the corneal tunnel. With the participation of Optosystems Ltd., we developed an algorithm and related software for using femtolaser keratotomy in the treatment of progressive keratoconus. These interventions were performed with 23 donor (cadaver) eyes that had been earlier rejected for a possible use in human keratoplasty. To assess the feasibility of the posterior lamellar keratoplasty using Femto Visum, we tested the surface quality of the ultrathin grafts prepared from 10 isolated corneal flaps.

Results. The proposed keratoplasty technology and the implantation of the intrastromal ring resulted in a complete corneal penetration free from adverse tissue bridges or adhesions. Following the kerato-pigmentation procedure, the gel-colored implant was found stably held in the preformed corneal tunnel; the remaining cornea areas remained intact. The femtolaser-assisted keratotomy resulted in radial incisions at the pre-determined locations. According to the roughness parameter, the surface quality of the ultrathin grafts produced with the femtosecond laser assistance was similar to that of the standard samples produced with a mechanical microkeratome.

Conclusion. The use of the Femto Visum femtosecond laser system in innovative areas of corneal surgery is effective and safe.

1. Krumeich J.H., Daniel J. Perforating keratoplasty with an intracorneal ring. Cornea 1999; 18(3): 277–281, https://doi.org/10.1 097/00003226-199905000-00006.
2. Krumeich J.H., Duncker G. Intrastromal corneal ring in penetrating keratoplasty: evidence-based update 4 years after implantation. J Cataract Refract Surg 2006; 32(6): 993–998, https://doi.org/10.1016/j.jcrs.2 006.02.020.
3. Kalinnikov Yu.Yu., Leont’eva G.D., Selifanov Yu.V., Bezzabotnov A.I., Zadorozhnyy S.V. Method of performing keratoplasty (versions). Patent RU 2589633. 2016.
4. Choyce D.P. Semirigid corneal in lays used the managment of albinism, aniridia and ametropia. In: XXIV International Congress of ophthalmology. Acta, San Francisco; 1982; p. 1230–1234.
5. Venger G.E. Vosstanovitel’naya khirurgiya raduzhnoy obolochki pri travmakh glaza i ikh iskhodakh. Avtoref. dis. … dokt. med. nauk [Iris reconstructive surgery in case of eye injuries and their outcomes. PhD Thesis]. Odessa; 1984.
6. Fedorov S.N., Zuev V.K., Vagrov S.N., et al. Surgical correction of aniridia and iris defects. Oftal’mokhirurgiya 1990; 2: 20–22.
7. Rodríguez A., Alió J., Amesty M., Bahrawy M. Text and atlas on corneal pigmentation. Jaypee Brothers Medical Publishers (P) Ltd.; 2015,https://do i.org/10.5005/jp/books/12571.
8. Bowman C.B., Thompson K.P., Stulting R.D. Refractive keratotomy in keratoconus suspects. J Refract Surg 1995; 11(3): 202–206.
9. Grandon S.C., Weber R.A. Radial keratotomy in patients with atypical inferior steepening. J Cataract Refract Surg 1994; 20(6): 670–671,https://doi.org/1 0.1016/s0886-3350(13)80171-x.
10. Kopaeva V.G., Leykina S.L., Tekari M. Keratotomiya v korrektsii ametropii pri keratokonuse. V kn.: Mezhdunarododnyy simpozium po refraktsionnoy khirurgii [Keratotomy for the correction of ametropia in keratoconus. In: International symposium on refractive surgery]. Moscow; 1991; p. 54.
11. Ivashina A.I. Khirurgicheskaya korrektsiya blizorukosti metodom peredney radialnoy keratotomii. Dis. … dokt. med. nauk [Surgical correction of myopia using anterior radial keratotomy. DSc Dissertation]. Moscow; 1989.
12. Lombardi M., Abbondanza M. Asymmetric radial keratotomy for the correction of keratoconus. J Refract Surg 1997; 13(3): 302–307.
13. Abbondanza M., Abdolrahimzadeh B., Guidobaldi M. Combined corneal collagen cross-linking and mini asymmetric radial keratotomy for the treatment of keratoconus. Acta Med Int 2016; 3(1): 63, https://doi.org/10.5 530/ami.2016.1.14.
14. Kocak I., Aydin A., Kaya F., Baybora H., Bozkurt S. Efficacy of radial keratotomy in the optical rehabilitation of mild to moderate keratoconus cases. Int Eye Sci 2015; 15(4): 572–576.
15. Fujimoto K., Osawa H., Moriyama T., Miyamoto T., Irie T., Nishimura T., Inoue T. Long-term stability of minimally invasive radial keratotomy for mild to moderate keratoconus. Asia Pac J Ophthalmol 2017; 6(5): 407–411,https://doi.org/10.22608/ap o .2016204.
16. Utine C.A., Bayraktar S., Kaya V., Kucuksumer Y., Eren H., Perente I., Yilmaz O.F. Radial keratotomy for the optical rehabilitation of mild to moderate keratoconus: more than 5 years experience. Eur J Ophthalmol 2006; 16(3): 376–384.
17. Durand L., Monnot J.P., Burillon C., Assi A. Complications of radial keratotomy: eyes with keratoconus and late wound dehiscence. Refract Corneal Surg 1992; 8(4): 311–314.
18. Panda A., Sharma N., Kumar A. Ruptured globe 10 years after radialkeratotomy. J Refract Surg 1999; 15(1): 64–65.
19. Malyugin B.E., Moroz Z.I., Kovshun E.V., Drozdov I.V. Zadnyaya avtomatizirovannaya posloynaya keratoplastika s ispol’zovaniem ul’tratonkikh transplantatov. V kn.: IX s”ezd oftal’mologov Rossii: tezisy dokladov [Dorsal automated lamellar keratoplasty using ultrathin grafts. In: IX Congress of Russian ophthalmologists: abstracts of reports]. Moscow; 2010; p. 310.
20. Busin M., Patel A.K., Scorcia V., Ponzin D. Microkeratome-assisted preparation of ultrathin grafts for descemet stripping automated endothelial keratoplasty. Invest Ophthalmol Vis Sci 2012; 53(1): 521–524, https://doi.org/10.1167/io vs. 11-7753.
21. Sikder S., Nordgren R.N., Neravetla S.R., Moshirfar M. Ultra-thin donor tissue preparation for endothelial keratoplasty with a double-pass microkeratome. Am J Ophthalmol 2011; 152(2): 202–208.e2, https://doi.org/10.1016/j. ajo.2011.01.051.
22. Cheng Y.Y., Schouten J.S., Tahzib N.G., Wijdh R.J., Pels E., van Cleynenbreugel H., Eggink C.A., Rijneveld W.J., Nuijts R.M. Efficacy and safety of femtosecond laser-assisted corneal endothelial keratoplasty: a randomized multicenter clinical trial. Transplantation 2009; 88(11): 1294–1302, https://doi.org/10 .1097/tp.0b013e3181bc419c.
23. Cheng Y.Y., van den Berg T.J., Schouten J.S., Pels E., Wijdh R.J., van Cleynenbreugel H., Eggink C.A., Rijneveld W.J., Nuijts R.M. Quality of vision after femtosecond laser-assisted descemet stripping endothelial keratoplasty and penetrating keratoplasty: a randomized, multicenter clinical trial. Am J Ophthalmol 2011; 152(4): 556–566.e1, https://doi.org/10.1016/j.ajo.2011.03.012 .
24. Izmaylova S.B., Malyugin B.E., Novikov S.V., Zimina M.V. Method of carrying out keratoplasty with one-momentary implantation of the intrastomal ring. Patent RU 2646588. 2017.
25. Izmaylova S.B., Novikov S.V., Zimina M.V., Chuprin V.V. Method of carrying out keratoplasty with one-momentary implantation of the intrastomal ring for the prevention of postoperative astigmatism. Application for a patent RU 2018104821.2018.
26. Izmaylova S.B., Novikov S.V., Sobolev N.P., Yarovoy A.A., Komarova O.Yu. Method of surgical treatment of aniridia with ametropia. Application for a patent RU 2017135291. 2017.
27. Izmaylova S.B., Vartapetov S.K., Konovalova M.M., Burdel K.V. Method for the treatment of keratoconus stage I–III (versions). Application for a patent RU 2018101843. 2018.
28. Alió J.L., Rodriguez A.E., Toffaha B.T., Piñero D.P., Moreno L.J. Femtosecond-assisted keratopigmentation for functional and cosmetic restoration in essential iris atrophy. J Cataract Refract Surg 2011; 37(10): 1744–1747, https://doi.org/10.1016/j.jcrs.2011.08.003 .

Komarova O.Yu., Lapshin K.E., Burdel K.V., Shatskikh A.V., Zimina M.V., Pashtaev A.N., Novikov S.V., Vartapetov S.K., Izmailova S.B. Innovative Technologies in Experimental Corneal Surgery ex vivo. Sovremennye tehnologii v medicine 2018; 10(4): 84, https://doi.org/10.17691/stm2018.10.4.10