Construction Solutions to Prevent Development of Secondary Cataract After Intraocular Lenses Implantation

Abstract

Background. The development of secondary cataract after implantation of an intraocular lens (IOL) as a result of migration and reproduction of residual epithelial cells after phacoemulsification occurs in 45–78% of patients. The currently used IOL models do not adequately protect the posterior part of the lens capsule and the front surface of the lens from the deposition of epithelial cells on them. Objective. The aims of the paper are as follows: (1) modeling the process of development of secondary cataract due to proliferation, migration and metaplasia of residual epithelial cells (E-LEC); (2) evaluation of existing technical solutions to combat clouding of the lens capsule (CLC), secondary cataract, after implantation of IOL; (3) development of original technical approach to solving the problem of CLC with next modeling; (4) conducting an experiment to study the movement of a dye solution in an extracted pig's eye lens, implanted with a Support OP lens based on the data obtained during simulation. Methods. To model the migration of epithelial cells, the COMSOL Multiphysics 5.4 software environment and the Fluid flow library were used. For computer analysis, IOL of our own design and the lens of an American company were taken. During the simulation, it was taken into account that cells of a polygonal or oval shape have sizes from 48 to 142 μm and a constant propagation velocity of 10 - 4 m/s. The main attention was paid to the spread of epithelial cells not only towards the posterior wall of the lens capsule, but also to the front surface of the lens itself. After carrying out computer modeling, the results of which have been repeatedly confirmed, an experiment was carried out in which a capsule bag of a pig's eye lens was implanted with an implanted IOL of its own design. An aqueous dye solution, applied under a pressure not exceeding the penetration strength of the lens capsule, imitated the movement of epithelial cells. The study was conducted in compliance with the ARRIVE guidelines. Results. The simulation showed that the use of the IOL sharp edge design just partially protects the back wall of the capsule from the growth of epithelial cells (E-cells) on it, despite the fact that the lens is made of hydrophobic acrylic. This IOL doesn’t tightly contact with the back wall of the capsule and therefore the migration of lens epithelial cells in this direction is possible. The front of the lens also remains vulnerable to fibrous hyperplasia, which leads not only to visual impairment, but also to its complete loss. The proposed volume-replacing IOL of its own design, which has a sharp edge, which provides close contact with the lens capsule, a groove-trap for migrating cells, and in the front of the elements for suture fixation. Conclusions. The study revealed a number of factors that need to be addressed to prevent the development of secondary cataract. The intraocular lens must be made of biocompatible material, for the full tension of lens capsule, it is necessary that the haptic is angulated, the optical part should include at least one of the elements (a sharp edge or a special side). Based on this, the proposed approach takes into account the problems described in the article and includes the above elements and a special groove-trap for epithelial cells. Modeling and experimental testing of the proposed option confirmed its effectiveness.