Keratokonus Hastalığında İnsan Korneasının Aşınma Analizi

Öz

Kornea, gözün ön kısmında bulunan, ışığı odaklamak ve gözü dış etkenlerden korumak için özelleşmiş şeffaf ve kavisli bir dokudur. Korneanın göz ve görme sistemi yapısındaki önemi, şeffaf yapısı nedeniyle çoğu zaman gözden kaçmaktadır. Kornea, retinanın karmaşık nörobiyolojik yapısından ve merceğin dinamik yapısından yoksundur, ancak buna rağmen, gözün bu organında şeffaflık olmadan düzgün bir şekilde çalışamaz. Korneanın şeffaf olmasını sağlayan yapı ve işlevinin karmaşıklığı, görsel sistemin en önemli bileşenlerinden birini incelememize neden olan bir sürprizdir. Kornea, enfeksiyonun yayılmasının önündeki ilk bariyer görevi gören damarsız bir bağ dokusudur. Kornea şeffaflığı, hücresel bileşenlerinin yapısal anatomisi ve fizyolojisi dahil olmak üzere çeşitli faktörlerden kaynaklanmaktadır. Keratokonus, korneanın deforme olduğu ve koni şeklinde öne çıktığı bir göz rahatsızlığıdır. Korneada meydana gelen bu değişiklik, gelen ışığın görme alanında odaklanamamasına neden olur. Sonuç, bulanık ve çarpık görmedir. Ayrıca göz ovuşturmanın hastalığın başlangıcında ve ilerlemesinde etkili olabileceğini gösteren çalışmalar da mevcuttur. Bu çalışmada keratakonus hastalığında göz ovuşturma sonucu oluşan aşınma sonlu elemanlar yöntemiyle incelenmiştir. Korneada deformasyon ve stres analizi araştırılmıştır. SEY, keratakonus hastalığından sonra kornanın biyomekanik davranışını tahmin etmeye yardımcı olabilir. kontakt noktasında ovuşturma etkisinden dolayı contact basınç, vonmises gerilme ve aşınma en ust değerine ulaşmaktadır

Anahtar Kelimeler

• Aşınma
• Kornea
• Sonlu Elemanlar Yöntemi.

Wear Analysis of Human Cornea in Keratoconus Disease

Abstract

The cornea is a transparent and curved tissue located at the front of the eye, specialized to focus light and protect the eye from external factors. The importance of the cornea in the structure of the eye and visual system is often overlooked because of its transparent nature. The cornea lacks the complex neurobiological structure of the retina and the dynamic nature of the lens, but despite this, it is unable to function properly without transparency in this organ of the eye. The complexity of the structure and function of the cornea, which makes it transparent, is a surprise that led us to examine one of the most important components of the visual system. The cornea is a vascular-free connective tissue that serves as the first barrier to the spread of infection to It acts inside the eyeball as well as the building block of the eye wall. Corneal transparency is due to several factors, including the structural anatomy and physiology of its cellular components. Keratoconus is an eye condition in which the cornea deforms and protrudes forward in a cone shape. This change that occurs in the cornea causes the incoming light to be unable to focus in the visual field. The result is blurred and distorted vision. There are also studies showing that eye rubbing can be effective in the onset and progression of the disease. In this study, wear from eye rubbing in kerataconus disease was analyzed by means of finite elements. Deformation and stress analysis in the cornea were investigated. FEM can help to predict biomechanichal behavior of corna after kerataconus dises. Due to the rubbing effect at the contact point, contact pressure, vonmises stress and wear reach their maximum value.

Keywords

• Wear
• Cornea
• Finite Elements Methods

Kaynakça

1. Wang, S., & Chester, S. A. (2021). Multi-physics modeling and finite element formulation of corneal UV cross-linking. Biomechanics and Modeling in Mechanobiology, 1-18.
2. Birkenfeld, J. S., Curatolo, A., Eliasy, A., Martinez-Enriquez, E., Varea, A., Ramos, A. M. G., ... & Marcos, S. (2022). Corneal biomechanical parameters from keratoconus patients using cross-meridian air-puff deformation optical coherence tomography and finite element modeling
3. Isaacson, A., Swioklo, S., & Connon, C. J. (2018). 3D bioprinting of a corneal stroma equivalent. Experimental eye research, 173, 188-193.
4. Elsheikh, A. (2010). Finite element modeling of corneal biomechanical behavior. Journal of Refractive Surgery, 26(4), 289-300.
5. Pinsky, P. M., & Datye, D. V. (1991). A microstructurally-based finite element model of the incised human cornea. Journal of biomechanics, 24(10), 907-922.
6. Roy, A. S., & Dupps, W. J. (2009). Effects of altered corneal stiffness on native and postoperative LASIK corneal biomechanical behavior: a whole-eye finite element analysis. Journal of refractive surgery, 25(10), 875-887.
7. Spevak, L. F., & Babailov, N. A. (2020, December). A finite element model of the stress-strain state of the human cornea. In AIP Conference Proceedings (Vol. 2315, No. 1, p. 040038). AIP Publishing LLC.
8. Birkenfeld, J. S., Curatolo, A., Eliasy, A., Martinez-Enriquez, E., Varea, A., Ramos, A. M. G., & Marcos, S. (2022). Corneal biomechanical parameters from keratoconus patients using cross-meridian air-puff deformation optical coherence tomography and finite element modeling.

9. Huang, L., Shen, M., Liu, T., Zhang, Y., & Wang, Y. (2020). Inverse solution of corneal material parameters based on non-contact tonometry: A comparative study of different constitutive models. Journal of Biomechanics, 112, 110055.
10. Karimi, A., Meimani, N., Razaghi, R., Rahmati, S. M., Jadidi, K., & Rostami, M. (2018). Biomechanics of the healthy and keratoconic corneas: a combination of the clinical data, finite element analysis, and artificial neural network. Current pharmaceutical design, 24(37), 4474-4483.
11. Velázquez Blázquez, J. S., Cavas Martínez, F., Bolarín Guillén, J. M., & Alió Sanz, J. L. (2020). Comparison of corneal morphologic parameters and high order aberrations in keratoconus and normal eyes.
12. Perone, J. M., Conart, J. B., Bertaux, P. J., Sujet-Perone, N., Ouamara, N., Sot, M., & Henry, J. J. (2017). Mechanical modeling of a keratoconic cornea. Cornea, 36(10), 1263-1266.
13. Zamanlou, H., & Karabudak, F. (2021). Comparison of Mechanical Fatigue for Human Cornea before and after CCL in. 22. Ulusal Mekanik Kongresine (p. 250). TUMTMK.
14. Vijay, R., Kumar, V. A., Sadiq, A., & Pillai, R. R. (2021, February). Numerical Analysis of Wear Characteristics of Zirconia Coated Aluminum 6061 Alloy. In IOP Conference Series: Materials Science and Engineering (Vol. 1059, No. 1, p. 012020). IOP Publishing.
15. Thompson, J. M., & Thompson, M. K. (2006, January). A Proposal for the Calculation of Wear. In Proceedings Of The 2006 International Ansys Users Conference & Exhibition, Pittsburgh, Pa.
16. Bahrami, M., Culham, J. R., Yovanovich, M. M., & Schneider, G. E. (2004). Thermal contact resistance of nonconforming rough surfaces, part 1: contact mechanics model. Journal of Thermophysics and Heat Transfer, 18(2), 209-217.
17. Jensen, F. (1985). Activation energies and the Arrhenius equation. Quality and Reliability Engineering International, 1(1), 13-17.
18. Nejad, T. M., Foster, C., & Gongal, D. (2014). Finite element modelling of cornea mechanics: a review. Arquivos brasileiros de oftalmologia, 77, 60-65.
19. Kehrer, T., & Mosquera, S. A. (2021). A simple cornea deformation model. Advanced Optical Technologies.
20. Ertan, A., & Colin, J. (2007). Intracorneal rings for keratoconus and keratectasia. Journal of Cataract & Refractive Surgery, 33(7), 1303-1314.
21. Sandner, D., Spoerl, E., Kohlhaas, M., Unger, G., & Pillunat, L. E. (2004). Collagen Crosslinking by Combined Riboflavin/Ultraviolet–A (UVA) Treatment can stop the progression of Keratoconus. Investigative Ophthalmology & Visual Science, 45(13), 2887-2887.
22. Stachura, J., Mlyniuk, P., Bloch, W., Jimenez‐Villar, A., Grulkowski, I., & Kaluzny, B. J. (2021). Shape of the anterior surface of the cornea after extended wear of silicone hydrogel soft contact lenses. Ophthalmic and Physiological Optics, 41(4), 683-690.
23. Del Castillo, L. F., Ramírez‐Calderón, J. G., Del Castillo, R. M., Aguilella‐Arzo, M., & Compañ, V. (2020). Corneal relaxation time estimation as a function of tear oxygen tension in human cornea during contact lens wear. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 108(1), 14-21.
24. Zhang, J., Li, J., Li, X., Li, F., & Wang, T. (2020). Redistribution of the corneal epithelium after overnight wear of orthokeratology contact lenses for myopia reduction. Contact Lens and Anterior Eye, 43(3), 232-237.
25. Moran, S., Gomez, L., Zuber, K., & Gatinel, D. (2020). A case-control study of keratoconus risk factors. Cornea, 39(6), 697-701.
26. Mathan, J. J., Gokul, A., Simkin, S. K., Meyer, J. J., Patel, D. V., & McGhee, C. N. (2020). Topographic screening reveals keratoconus to be extremely common in Down syndrome. Clinical & Experimental Ophthalmology, 48(9), 1160-1167.
27. Bhat, B., Poojary, R. G., Prabhu, G., & Ve, R. S. (2021). FEM Based Study for Estimation of Applanation Force and Influence of Intraocular Pressure on Tonometry. GZAIEL, M., TRIKI, E., BARKAOUI, A., & CHAFRA, M. Finite element modeling of energy-state in combined puncture/cutting of soft material by a pointed blade.