METHOD FOR DETERMINING OPTICAL POWER OF INTRAOCULAR LENS BASED ON PERSONAL SURGICAL TECHNIQUE AND PREOPERATIVE DATA Russian patent published in 2022 - IPC A61F2/16 

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to ophthalmic surgery. To calculate the optical power of the intraocular lens (IOL), a test sample is formed from the IOL implantation data, containing at least ten patient records. The required parameters are: the average radius of curvature of the anterior surface of the cornea (R, mm), the axial length of the eye (AL, mm), the depth of the anterior chamber before surgery (ACD, mm), the optical power of the implanted IOL (P_{IOL_impl}, diopters), the target postoperative refraction ( Ref_target, diopters), postoperative subjective refraction after at least one month (Ref_p/o, diopter), postoperative depth of the anterior chamber - the distance from the anterior surface of the cornea to the anterior surface of the IOL (ACD_p/o, diopter). If available, include parameters: corneal thickness in the central zone (CCT, mm), average curvature of the posterior surface of the cornea (Rz, mm), lens thickness in the central zone (LT, mm), corneal diameter (W, mm), A-constant of the implanted IOL (A_const). According to the test sample data, the optical power of the cornea (P_cor, diopter) is calculated, and the optical power of the eye (P_eye, diopter) and the distance between the second focal point of the cornea and the first focal point of the IOL (N_IOL, mm) are determined by approximating the set of functions. In general, the formula for calculating the IOL has the form

where nwater.moisture is the refractive index of aqueous humor. Using combinations of functions that calculate P_cor, Peye, N_IOL, methods for calculating the optical power of the IOL are formed, which are then used to calculate P_IOL on a test sample. Based on the calculation results, deviations (delta, mm) from the target refraction are calculated for each combination using the formula delta=PIOL-P_{IOL_target}. From the array of calculation formulas, those are selected for which the share of deviations from the target refraction will be no more than ±1 diopter in 85% of cases. After that, the formulas are grouped according to the number and type of parameters included in them for calculation, and in each group for clinical use, the one that has the minimum absolute average value of delta is selected.

EFFECT: application of the invention will improve the accuracy of the calculation of the optical power of the IOL and will provide a breadth of application of the method for any surgical technique and preoperative data.

10 cl, 3 dwg, 6 tbl

P_ИОЛ - P_IOL

P_глаз - P_eye

P_рог - P_cor

N_ИОЛ - N_IOL

n_{вод.влаги} - n_{water.moisture}

Ref_цель - Ref_target