Intraocular Lens Optic Power Calculation on “Short” Eyes. A Review

In recent years, due to advances in surgical technique, instruments and design of intraocular lenses (IOLs), patient expectations of cataract surgery have increased significantly, often matching those after refractive interventions. A number of factors affect postoperative visual acuity, including the presence of concomitant pathology in patients, the experience of the surgeon, the choice of IOL model and other factors. In the presence of “short” eyes, with an axial length of less than 22 mm, the formulas available in the arsenal for calculating the optical power of the IOL are less accurate than for eyes with normal sizes, which is of great difficulty for the surgeon. The most important factors include the choice of model and calculation of IOL optic power associated in case of failure with patient dissatisfaction with the treatment. The review discusses the definitions of the concepts of hyperopia, microphthalmos and nanophthalmos. The sources of errors are presented when choosing a formula for calculating the IOL optic power, including the use of various instruments for measuring axial length and other parameters of the eye. The necessity of optimizing the IOL constants for “short” eyes is given. The effectiveness of the main currently used formulas is considered, including Hoffer Q, Haigis, Holladay 1, Holladay 2, SRK / T, Barrett Universal, Super Formula, Olsen, T2, Hill-RBF, Kane. Progress in lens disease surgery does not stand still and is aimed at improving diagnostic equipment and standardizing and synchronizing various types of biometers, increasing the number of variables in formulas for calculating the IOL optic power, further standardizing diopter power in the manufacturing of IOLs, and the need to develop a unified formula for calculating optical power Artificial Intelligence IOL with the possibility of its constant access to a huge array of preoperative research data manhole and postoperative assessment of results. Management of patients with an axial length of less than 22.00 mm remains a challenge for ophthalmic surgeons, given the difficulties encountered in choosing an IOL and the complications of surgery. The available formulas for calculating the IOL optic powerneed to be adjusted for this group of patients. 

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