Shargorodskaya I. V.

P. L. Shupyk National Medical Academy of Postgraduate Education, Kyiv, Ukraine 

 Resume. The problem of the clinical studies of biomechanical properties and structures of the eye tissue has a long history, but still far from being solved. Measurement of corneal hysteresis (CH) using the analyzer cornea biochemical properties ocular response analyzer (ORA) became the world standard in the evaluation of the cornea biomechanical properties. Considerable achievements of last years in modern diagnostics and treatment of keratoconus have not removed an urgency of the given problem from the agenda as long as traditional notions about pathogenesis of the keratoconus not always allow to struggle effectively with this difficult and continuously progressing disease.

 Purpose. To carry out a comparative analysis of the measurements of corneal biomechanical parameters at keratoconus by using different methods.

Materials and methods. The 24 patients (48 eyes) with keratoconus were included in investigation. In the control group were included 20 patients (40 eyes) with emmetropic refraction. The corneal biomechanical parameters were carried out in the same patients by the use the comparative analysis between the measurements obtained of a well-known method in the evaluation ORA, the elastotonometry, module for monitoring Belin/Ambrosio ectasia (BAD) of chamber Oculus Pentacam device Sheimpflug by a standard technique and the indicators calculated with using way offered by us and the device for estimation of cornea rigidity in vivo. 

Results. It was registered the considerable advantages of using the developed new way and the device for estimation of cornea rigidity in vivo in comparison with ORA, elastotonometry, keratotopographic on Sheimpflug camera Oculus Pentacam which allowed not only to reveal presence of biomechanical infringements of cornea at keratoconus, but also to differentiate their character. The factor is developed for the description of change degree of biomechanical properties of cornea in vivo it was worked out the coefficient of cornea rigidity. Increase of coefficient of corneal rigidity (K_ER) above (+)6.4 % may serve as a criterion for progression of keratoconus. 

 Conclusions. Loading tests allow receive more exact information on biomechanical properties of cornea in comparison with standard researches on ORA, elastotonometry and Sheimpflug camera Oculus Pentacam.

 Keywords: keratoconus, cornea, biomechanical properties, coefficient of cornea rigidity, elastotonometry, ORA, Oculus Pentacam.

REFERENCES

1. Avetisov S. E. Mamikonyan V. R., Zavalishin N. N., Nenyukov A. K. Experimental study of mechanical properties of the cornea and sclera adjacent areas. Oftalmologicheskiy zhurnal [Journal of Ophthalmology]. 1988; (4): 233–237 (in Russian).
2. Avetisov E. S. Myopia. Moscow, Medicina, 1999, 303 p. (in Russian).
3. Bakbardin Y. V., Kondratenko U. N. Tonometric, tonographic and gonioskopic research methods. Kyiv, 1998, 33 p. (in Russian).
4. Erichev V. P., Eremina M. V., Yakubova L. V., Arezheva Yu. A. Corneal hysteresis in normal conditions and in certain types of ophthalmopathology. Proceeding of the “Biomekhanika glaza – 2007” (Russia, Moscow, 2007). Moscow, 2007, pp. 82–87 (in Russian).
5. Kalfa S. F. Sbornik nauchnih rabot glaznoy kliniki Odeskogo medicinskogo instituta [Collected scientific. Works Eye Clinic of the Odessa Medical Institute]. 1936; (1): 51–132 (in Russian).
6. Kivaev A. A., Babich G. A., Abugova T. D. Dynamics biomicroscopy of the cornea changes in keratoconus. Oftalmologicheskiy zhurnal [Journal of Ophthalmology]. 1979; (4): 217–218 (in Russian).
7. Korostelyova N. F., Koeman I. G., Evlampiev V. A. Differential diagnosis of atypical flat choroidal detachments and peripheral partial retinal detachments in the eyes bleary optical media. Oftalmohirurgiya [Ophthalmosurgery]. 1992; (4): 34–38 (in Russian).
8. Kotlyar K. E., Iomdin E. N., Koshits J. H. Biomechanics eyes as a highly effective tool for the selection and development of promising areas of clinical and experimental studies. Proceedings of the “Biomekhanika glaza” (Russia, Moscow, 2004). Moscow, 2004, pp. 3–8 (in Russian).
9. Moiseienko R. O., Holubchykov M. V., Slabkyi H. O., Rykov S. O. Ophthalmological help in Ukraine for 2006–2011. Kyiv, 2012, 183 p. (in Ukrainian).
10. Obrubov S. A., Sidorenko E. I., Fedorova V. N., Dubovaya T. K., Dreval A. A. Acoustic biomechanics of the eye and its significance for the clinic. Moscow, 2001, 128 p. (in Russian).
11. Obrubov S. A., Sidorenko E. I., Dreval A. A., Grischenko S. V. Biomechanical properties of sclera depending on the degree of differentiation. Proceedings of the “Biomekhanika glaza” (Russia, Moscow, 2004). Moscow, 2004, pp. 67–69 (in Russian).
12. Sergienko N. M., Shargorodskaya I. V. A method of estimating the rigidity of the cornea. Ukraine. Patent 39262, February 25, 2009 (in Russian).
13. Sergienko N. M., Shargorodskaya I. V. The device for assessing the stiffness of the cornea. Ukraine. Patent 85810, February 25, 2009 (in Russian).
14. Puchkovskaya N. A. Shulgin N. S., Bushueva N. N. Features predict further progression of myopia complicated. Proceedings of the “Patopoligya glaznogo dna” (Russia, Moscow, 1986). Moscow, 1986, pp. 78–79 (in Russian).
15. Rykov S. A. Scientific substantiation of system of providing eye care to the population of Ukraine. Dr. Med. Sci. Diss. Kyiv, 2004, 527 p. (in Russian).
16. Tarutta E. P. Sclera treatment and prevention of complications of progressive myopia in children and adolescents. Dr. Sc. Thesis. Moscow, 1993, 51 p. (in Russian).
17. Ferflfayn I. L. On the question of classification of myopia. Dnepropetrovsk, 1999, pp. 96– 102 (in Russian).
18. Shargorodskaya I. V. Comparative analysis of the measurements of biomechanical parameters of the cornea using various methods. Arhiv oftalmologii Ukraini [Archives of Ophthalmology Ukraine]. 2016; (4): 61–66 (in Russian).
19. Amsler M. La notion du keratocone. Bull Soc Franc Ophthalmol. 1951; (64): 272–275.
20. Bell G. R. Biomechanical consideration of high myopia: Part I – Physiological characteristics. J Am Optom Assoc. 1993; (64): 332–338.
21. Blach R. K. Degenerative myopia. In: Krill A. E., Archer D. B., eds. Krill’s hereditary retinal and choroidal diseases. Maryland, Harper and Row, 1977; (2): 911–937.
22. Bron A. J. Keratoconus. Cornea. 1988; (163): 163–169.
23. Curtin B. J. The myopias: Basic Science and clinical management. Philadelphia, 1985, 120 p.
24. Duke-Elder S., Leigh A. G. Keratoconus. System of Ophthalmology. 1965; (8): 964–976.
25. Grabner G., Eilmdteiner R., Steindl C., Ruckhofer J., [et al.] Dynamic corneal imaging. J Cataract Refract Surg. 2005; (31): 163–174.
26. Greene P. R. Closed-form ametropic pressure-volume and ocular rigidity solutions. Am J Optom Physiol Opt. 1985; (62): 870–878.
27. Haque S., Simpson T., Jones L. Corneal and epithelial thickness in keratoconus: a comparison of ultrasonic pachymetry, Orbscan II, and optical coherence tomography. J Cataract Refract Surg. 2006; (22): 486–493.
28. Jaycock P. D., Lobo L., Ibrahim J., Tyrer J., Marshall J. Interferometric technique to measure biomechanical changes in the cornea induced by refractive surgery. J Cataract Refract Surg. 2005; (31): 175–184.
29. Lichtinger A., Rootman D. S. Intraocular lenses for presbyopia correction: past, present, and future. Curr Opin Ophthalmol. 2012; (23): 40–46.
30. Maeda N. Artificial intelligence schemes for classification of corneal topography. Proceedings of the International Society for Eye Research (USA, New Mexico, Santa Fe, 2000). New Mexico, 2000; (14): 70.
31. Patel S., McLaren J., Hodge D., Bourne W. Normal human keratocyte density and corneal thickness measurement by using confocal microscopy in vivo. Invest Ophthalmol Vis Sci. 2001; (42): 333–339.
32. Sergienko N. M., Shargorodska I. V. Determining corneal hysteresis and preexisting intraocular pressure. J Cataract Refract Surg. 2009; (35): 2033–2034.
33. Simon G., Small R. H., Ren Q., Parel J. M. Effect of corneal hydration on Goldman applanation tonometry and corneal topography. Refract Corneal Surg. 1993; (9): 110–117.
34. Ucakhan O. O., Kanpolat A., Ylmaz N., Ozkan M. In vivo confocal microscopy findings in keratoconus. Eye Contact Lens. 2006; (32): 183–191.
35. Wollensak J., Ihme A., Seiler T. Neue Befunde bei Keratokonus. Fortschr Ophthalmol. 1987; (84): 28–32.

Received: 13 May 2016

Published: December 2016