Evolution and properties of polymeric synthetic materials for contact lenses: a literature review

Background. The global and Russian contact lens markets are experiencing dynamic growth, encompassing several distinct classes of lenses that differ in structure and properties. However, Russia currently lacks domestic base materials for the manufacturing of contact lenses. This highlights the relevance of reviewing the available literature on lens production methods and the primary chemical materials used in their fabrication. Purpose: to identify the material structures used in contact lens manufacturing and to analyze the advantages and limitations of each class of materials. Materials and methods. A literature review was conducted involving 29 scientific publications focusing on contact lens fabrication techniques. The review highlights materials that have significantly influenced the development of the industry or have reached the commercial market. Results. This review traces the historical development and current trends in the use of various materials for contact lenses, including glass, polymethyl methacrylate (PMMA), hydrogels, and silicone hydrogels. It outlines the molecular structures of these materials: hydrogel lenses are typically composed of copolymers such as hydroxyethyl methacrylate, N-vinylpyrrolidone, N,N-dimethylacrylamide, and other organic monomers. Silicone hydrogel lenses incorporate these hydrophilic components along with silicone oligomers. Glass and PMMA lenses are characterized by excessive rigidity, making them uncomfortable for everyday wear. In contrast, hydrogel lenses provide more appropriate elasticity but fall short in delivering sufficient oxygen to the cornea. The primary focus of the review is on silicone hydrogel lenses. These materials are considered safe due to the bioinert nature of silicones. Ongoing research is directed toward improving the compatibility between hydrophilic and hydrophobic domains, refining the architecture of silicone macromers, enhancing surface modification techniques, and exploring new manufacturing methods. The article also examines four generations of commercially available silicone hydrogel materials and highlights an emerging direction in the field: biomimetic lenses based on methacryloxyethyl phosphorylcholine – a compound that closely mimics the structural characteristics of natural tissues. Conclusion. Compared to previous lens generations, silicone hydrogel lenses represent the most advanced class of materials to date. They offer superior comfort and are best suited for extended wear due to their optimal moisture retention, oxygen permeability, and elasticity. An emerging area of interest is the development of biomimetic contact lenses made from tissue-like polymeric structures.

1. Nichols JJ, Fisher D. Contact lenses 2020. Contact Lens Spectr. 2021;36:24–29.

2. Kakroo V. Contact lenses market size, share, and trends 2024 to 2033. Precedence Research. 2024. URL: https://www.precedenceresearch.com/contact-lenses-market (accessed 23.12.2024).

3. Jones L, Walsh K. The evolution of silicone hydrogel daily disposables. Two decades of material and design innovation. OPTICIAN. 2018;4:22–28. (In Russ.)

4. Stern J, Wong R, Naduvilath TJ, et al. Comparison of the performance of 6- or 30-night extended wear schedules with silicone hydrogel lenses over 3 years. Optometry and Vision Science. 2004;81(6):398–406. doi: 10.1097/01.opx.0000135092.69383.fd

5. Nilsson SE. Seven-day extended wear and 30-day continuous wear of high oxygen transmissibility soft silicone hydrogel contact lenses: A randomized 1-year study of 504 patients. CLAO Journal. 2001;27(3):125–136.

6. Perfilieva EA. Evolution of materials and design of soft contact lenses. The EYE GLAZ. 2018;20(2):10–14. (In Russ.)

7. Kireev VV. High-molecular compounds: a textbook for academic baccalaureate. Moscow: Yurayt Publ.; 2015:602. (In Russ.)

8. Musgrave CSA, Fang F. Contact lens materials: A materials science perspective. Materials (Basel). 2019;12(2):261. doi: 10.3390/ma12020261

9. Wuchte L, DiPasquale S, Masterson A, et al. Characterization and analysis of extended-wear silicone hydrogel contact lenses utilizing novel silicone macromers. J Biomed Mater Res A. 2022;110(8):1512–1523. doi: 10.1002/jbm.a.37389

10. dos Santos JF, Alvarez-Lorenzo C, Silva M, et al. Soft contact lenses functionalized with pendant cyclodextrins for controlled drug delivery. Biomaterials. 2009;30(7):1348–1355. doi: 10.1016/j.biomaterials.2008.11.016

11. Zhao Z, Xie H, An S, Jiang Y. The relationship between oxygen permeability and phase separation morphology of the multicomponent silicone hydrogels. J Phys Chem B. 2014;118(50):14640–14647. doi: 10.1021/jp507682k

12. Moad G. A critical assessment of the kinetics and mechanism of initiation of radical polymerization with commercially available dialkyldiazene initiators. Progress in Polymer Science. 2019;88:130–188. doi: 10.1016/j.progpolymsci.2018.08.003

13. Alió JL, Belda JI, Artola A, et al. Contact lens fitting to correct irregular astigmatism after corneal refractive surgery. Cataract Refract Surg. 2002;28(10):1750–1757. doi: 10.1016/s0886-3350(02)01489-x

14. Shishavan AA, Nordin L, Tjossem P, et al. PMMA-based ophthalmic contact lens for vision correction of strabismus. Proceedings of the SPIE. 2016;9918. doi: 10.1117/12.2237994

15. Thean, JHJ, Mcnab AA. Blepharoptosis in RGP and PMMA hard contact lens wearers. Clin Exp Optom. 2004;87(1):11–14. doi: 10.1111/j.1444-0938.2004.tb03139.x

16. Michálek J., Podešva J., Dušková-Smrčková M. True story of poly(2-hydroxyethyl methacrylate)-based contact lenses: How did it really happen. Substantia. 2022;6(2):79–91. doi: 10.36253/Substantia-1591

17. Kopecek J. Hydrogels: From soft contact lenses and implants to self-assembled nanomaterials. Journal of polymer science / Part A. Polymer chemistry. 2009;47(22):5929–5946. doi: 10.1002/pola.23607

18. Wichterle O, Lim D. Hydrophilic gels for biological use. Nature. 1960;185:117–118. doi: 10.1038/185117a0

19. Wichterle O. Method of centrifugally casting thin edged corneal contact lenses. Patent US3660545A – 1972-05-02.

20. Nicolson PC, Vogt J. Soft contact lens polymers: an evolution. Biomaterials. 2001;22(24):3273–3283. doi: 10.1016/s0142-9612(01)00165-x

21. Holden BA, Mertz GW. Critical oxygen levels to avoid corneal edema for daily and extended wear contact lenses. Invest Ophthalmol Vis Sci. 1984;25(10):1161–1167.

22. Harvitt DM, Bonanno JA. Re-evaluation of the oxygen diffusion model for predicting minimum contact lens Dk/t values needed to avoid corneal anoxia. Optom Vis Sci. 1999;76(10):712–719. doi: 10.1097/00006324-199910000-00023

23. Tighe BJ. Extended wear contact lenses. Biomaterials and Regenerative Medicine in Ophthalmology. 2010;304–336.

24. Voronkov MG, Mileshkevich VP, Yuzhelevsky YuA. The siloxane bond. Novosibirsk: Nauka; 1976:413. (In Russ.)

25. Kossovsky N, Freiman CJ. Physicochemical and immunological basis of silicone pathophysiology. J Biomater Sci Polym Ed. 1995;7(2):101–113. doi: 10.1163/156856295x00625

26. Habal MB. The biologic basis for the clinical application of the silicones. A correlate to their biocompatibility. Arch Surg. 1984;119(7):843–848. doi: 10.1001/ archsurg.1984.01390190081019

27. Key JE. Development of contact lenses and their worldwide use. Eye & Contact Lens. 2007;33(6):343–345. doi: 10.1097/ICL.0b013e318157c230

28. Gaylord NG. Oxygen-permeable contact lens composition methods and article of manufacture. Patent US3808178 – 30- 04-1974.

29. Nicholson PC, Baron RC, Chabrecek P, et al. Extended wear ophthalmic lens. Patent WO 96/31792 – 22-03-1996.

30. Ishihara K, Shi X, Fukazawa K, et al. Biomimetic-engineered silicone hydrogel contact lens materials. ACS Appl Bio Mater. 2023;6(9):3600–3616. doi: 10.1021/acsabm.3c00296

31. Harvey TB. Hydrophilic siloxane monomers and dimmers for contact lens materials and contact lenses fabricated therefrom. Patent US4711943 – 08-12-1987.

32. Iwata J, Hoki T, Ikawa S, Back A. Silicone hydrogel contact lens. Patent US8614261B2 – 20-09-2006.

33. Broad RA. Contact lens. Patent WO2008061992 – 29-05- 2008.

34. Ishihara K, Ueda T, Nakabayashi N. Preparation of phospholipid polymers and their properties as polymer hydrogel membranes. Polym J. 1990;22(5):355–360. doi: 10.1295/polymj.22.355

35. Willis SL, Court JL, Redman RP, et al. A novel phosphorylcholinecoated contact lens for extended wear use. Biomaterials. 2001;22(24):3261–3272. doi: 10.1016/S0142-9612(01)00164-8

36. Ishihara K, Pappas E, Pruitt D, et al. Innovations in contact correction: the creation of a biomimetic surface. The EYE GLAZ. 2023;25(3):235–243. (In Russ.) doi: 10.33791/2222-4408-2023-3-235-243.