evaluation of axial stability of two models of intraocular lenses in patients with an eye length more than 26 mm

Conditions: Cataract Senile; Myopia, High-Grade; Corneal Astigmatism

Summary: some parameters, such as a change in the optic tilt and axial decentration, can affect the optical characteristics of intraocular lenses (iols) in postoperative period, which leads to residual refractive errors and other complications. the stability of the intraocular lens in the eye is largely dependent on the mechanical design of its haptic support elements. thus, the new clareon iol has a flat haptic with a flexible design that minimizes axial changes and allows the iol to maintain a stable position in a given plane during compression. currently there is no published data of the stability for clareon autonome iol for long eyes. the purpose of the current study is to evaluate and compare the axis displacement and stability of optical tilt, visual and refractive results in patients after implantation of two different models of intraocular lenses: clareon autonome (alcon, usa) and hoya isert 251 (japan) in the long-term postoperative period (after cataract surgery).

the optical performance of intraocular lenses (iols) can be affected by changes in optic tilt and decentration that occur after implantation, resulting in residual refractive errors and other complications. intraocular lens stability is largely dependent on the mechanical design of the haptics. clareon iol has a flat haptic with a flexible design that minimizes axial changes and allows the iol to maintain a stable position in a given plane during compression. based on our knowledge, nobody has compared clareon autonome and hoya isert 251 iols in clinical setting. scientific rationale: this study investigates the stability of iols in patients with long axial length. iol stability on long eyes has a limited clinical data, no in vivo research has been done. it is known that eyes with long axial length have a large capsule bag. with such eyes, it is difficult to predict the effective lens position. each 0,5 mm axial displacement lead to approximately 0,5 d of the refractive error. for long eyes, it is important to use the latest generation of multi-component iol calculation formulas for accurately prediction of effective lens position. the mail purpose of the study is to evaluate and compare the axis displacement and stability of optical tilt, visual and refractive results in patients after implantation of two different models of intraocular lenses: clareon autonome (alcon, usa) and hoya isert 251 (japan) in the long-term postoperative period (after cataract surgery). the research purpose is to evaluate the prediction error for each iol calculation formula (barrett universal ii, kane, evo, holladay i with van koch correction)

Eligibility criteria:
inclusion criteria: * man or woman 50 years and older with indicated cataract surgery. * signed informed consent, given by the participant or his/her legal representative. * ability to understand russian spoken and written language. * sanitated oral cavity. * intraocular pressure in normal range. * axial eye length\> 26 mm. * corneal astigmatism \<1.0 diopters. * the presence of age-related cataract with high myopia and low visual acuity (less than 0.5 with correction), the cornea thickness in the central optical zone is not less than 500 microns and not more than 600 microns, and the density of endothelial cells is higher than 2300 cells / mm2. * patients who have passed the entire tests for hospitalization in hospital and also have received the admission (the conclusion) of the therapist for the surgery. exclusion criteria: * inability to give signed informed consent. * age under 50 years. * history of allergic reactions to antibiotics, glucocorticosteroids, medications for local and general anesthesia. * diagnosed neoplastic process or treatment for tumor disease. * positive tests for infectious: hiv, syphilis, hepatitis b, hepatitis c. * any medical, psychiatric and/or condition, including cachexia, or social conditions that the investigator believes would interfere with or contraindicate adherence to the research protocol or the ability to provide signed informed consent. * active ophthalmic infection. * uncontrolled glaucoma * retinal defunctioning (no light perception and/or retinal detachment). * absence of the electric activity of the optic nerve and/or retina. * concomitant ocular pathology, such as the subluxation of the lens, glaucoma, pathology of the central retina, diabetic retinopathy, scars and opacities of the cornea, keratoconus, pathology of the corneal endothelium (fuchs corneal dystrophy), pseudoexfoliative syndrome with pronounced impairment of the diaphragmatic function of the pupil, a non-functioning retina (lack of light perception and/or its detachment according to ultrasound examination), lack of electrical activity of the optic nerve and retina according to electrophysiological examination, etc. * patients with a serious general medical condition. * systemic use / administration of drugs that may affect the anatomical or functional characteristics of the cornea (amiodarone, β-blockers, tetracycline, etc.) * any pathology of the eye associated with myopia and myopic changes inside the eye (for example, myopic staphyloma) that may affect the results of the study. * regular intake of medications that may affect the proper function of the eye (antiglaucoma drugs, antibiotics, systemic immunosuppressive therapy, etc.) * systemic pathologies with possible damage to the cornea. * amblyopia. * any other concomitant ocular pathology, trauma or surgery in history. * a patient who cannot adhere to the schedule of visits for research or treatment (for example, patients from other cities). * suspected drug or alcohol abuse.

Keywords: axial stability, cataract surgery, iol, high myopia