Optimization of Constant «A» for “Open Bag” Iol «Torsion» Based on Personalized Parameters of the Anterior Segment of the Eye
Abstract
Purpose. To optimize constant «A» (SRK/T formula) for “Open bag” IOL «Torsion» depending on individual parameters of the anterior segment of the eye.
Material and methods. The personalized distance from the corneal surface to the posterior capsule of the lens (PCL) of the eye has been determined as the basis for optimization of constant «A». The postoperative position of the IOL has been analyzed and, taking into account the known value of the average constant «A», the optimized constant «A» has been calculated. A comparative analysis of the refractive error has been performed using the average and optimized constant «A».
Results. Optimized practical constants «A» for ultrasound and optical biometry have been calculated depending on individual eye parameters. A reduction in refractive error has been demonstrated during implantation of the “Torsion” IOL using the optimized constant «A».
Conclusions. Optimized constants «A» were determined for calculating the optical power of the “Torsion” IOL based on personalized values of preoperative values of the distance from the cornea to the posterior capsule of the lens.
The use of the optimized constant «A» allows to reduce the refractive error when calculating the “Open bag” Torsion IOL compared to the use of the average value of the constant «A» for the SRK/T formula.
About the Authors
D. V. Logunov
Пензенский институт усовершенствования врачей – филиал ФГБОУ ДПО «Российская медицинская академия непрерывного профессионального образования»
Russian Federation
Russian Federation
S. L. Kuznetsov
Пензенский институт усовершенствования врачей – филиал ФГБОУ ДПО «Российская медицинская академия непрерывного профессионального образования»
Russian Federation
Russian Federation
A. A. Malikova
Пензенский институт усовершенствования врачей – филиал ФГБОУ ДПО «Российская медицинская академия непрерывного профессионального образования»
Russian Federation
Russian Federation
References
1. Ivan Fernandez-Bueno, Luis Ignacio Olcina, Cristina Andrés-Iglesias, Kevin Puertas-NeyraItziar, Fernández-Martínez, Ricardo Usategui-Martín, Miguel José Maldonado-López. Safety, biocompatibility, and potential functionality of a new accommodative intraocular lens: An experimental study in rabbits. J. Heliyon. 2023; 9(9). (in Engl) DOI: 10.1016/j.heliyon. 2023.e19604
2. Elinor Megiddo-Barnir, Guy Kleinmann. Influence of the CleaRing intraocular open capsule device on refractive predictability in cataract surgery. Clin. Exp. Ophthalmol. 2023; 51(7): 685-691. (in Engl) DOI: 10.1111/ceo.14282
3. Bontu, Sneha; Werner, Liliana; Kennedy, Sean; Kamae, Kai; Jiang, Bill; Ellis, Nathan; Brady, Daniel G. BEng, MBA; Mamalis, Nick. Long-term uveal and capsular biocompatibility of a new fluid-filled, modular accommodating intraocular lens. Journal of Cataract & Refractive Surgery. 2021; 47(1): 111-117. (in Engl) DOI: 10.1097/j.jcrs.0000000000000391
4. Werner, L. The open/expanded-bag intraocular lens concept. J. Cataract Refract Surg. 2022; 48(10): 1103-1104. (in Engl) DOI: 10.1097/j.jcrs.0000000000001014
5. Zuev V.K., Panteleev E.N., Bessarabov A.N., Veshchikova V.N., Frankovska-Gerlak M.Z., Sorokoletov G.V. Raschet konstanty A dlya elastichnoi «reversnoi» IOL. Oftal'mokhirurgiya. 2015; 4:6-9. (in Russ)
6. Kuznecov S.L., Logunov D.V., Brazhalovich E.E. Polozhenie zadnej kapsuly artifakichnogo glaza ob''emozameshhajushhej IOL s «torsionnoj» gaptikoj MIOL-28 (The position of the posterior capsule of the artificial eye of a volumetric IOL with a «torsion» haptic MYOL-28). Vestnik Tambovskogo universiteta. Serija: Estestvennye i tehnicheskie nauki. 2016; 4:1591-1596. (in Russ)
7. Elastichnaya intraokulyarnaya linza s torsionnoi gaptikoi (Elastic intraocular lens with torsional haptics): patent № 2208418 Ros. Federacija; zajavl. 08.06.2001; opubl. 20.07.2003. Bjul. №20. (in Russ)
8. Kuznetsov S.L., Uzunyan D.G., Zakhidov A.B., Novikov S.V., Selifanov Yu.V. IOL s torsionnoi gaptikoi. Klinicheskie rezul'taty izucheniya ob''emozameshchayushchei modeli IOL with «torsion» haptics. (Clinical results of studying the volume-substituting model). Oftal'mokhirurgiya. 2010; 2:24-29. (in Russ)
9. Holladay J.T. Standaridizing constants for ultrasonic biometry, keratometry, and intraocular lens power calculation. J. Cataract Refr. Surg. 1997; 23:1356-1370. (in Engl)
10. Cooke David L, Waldron Rhonda, Savini Giacomo, Riaz Kamran M Taroni Leonardo, Murphy David A., Guaraldi Fabio. Immersion ultrasound biometry vs optical biometry. J. Cataract Refr. Surg. 2022; 48(7):819-825. (in Engl) DOI: 10.1097/j.jcrs.0000000000000865
11. Lens Constants. East Valley Ophthalmology Eye Doctors Mesa AZ. Optical Biometry Lens Constants. [Electronic resource] URL: https://doctor-hill.com/iol-power-calculations/optical-biometry/lens-constants/(date of access: 01.02.2025) (in Engl)
Review
For citations:
Logunov D.V., Kuznetsov S.L., Malikova A.A. Optimization of Constant «A» for “Open Bag” Iol «Torsion» Based on Personalized Parameters of the Anterior Segment of the Eye. Bashkortostan Medical Journal. 2025;20(2):55-59. (In Russ.)
Views:
10
Email this article 
