The subject of the study is the relative acoustic density obtained using the ultrasound scan, and its relationship with the mechanical density of the lens. The purpose of the study: to increase the efficiency of surgical treatment of patients with age-related cataracts by developing differential indications for the use of ultrasound phacoemulsification or ultrasonic phacoemulsification using a femtosecond laser based on the determination of the acoustic density of the lens. Research methods: visomometry according to Golovin-Sivtsev's table, biomicroscopy, ophthalmoscopy, tonometry, ultrasonic A scanning on the apparatus of OcuScan RxP, ultrasonic scanning on Quantel Medical Cinescan, computer densitometry, methods of statistical data processing. The correlation between the optical and acoustic density of the lens, which is most pronounced in the anterior third (R = 0.75), is connected with the effect of ultrasonic signal dissipation in the study of the lens. It is established that to calculate the supposed ultrasonic energy required for emulsification of age cataracts, it is necessary to use the data of acoustic density in the anterior third of the lens (R = +0,86). The strength required for penetration of needles of various structures into an in-vitro high density lens with a high density is 65.4 ± 3.6 g using an advanced needle and 104.1 ± 4.3 g for a standard needle for phacoemulsification was found. The mathematical model of calculation of the total ultrasonic energy is developed, which includes the necessity of taking into account the parameters of acoustic density of the lens and allows to specify the possibility of using ultrasonic phacoemulsification as an independent method or ultrasonic phacoemulsification using a femtosecond laser. A computer program was developed, which allows, based on the data of densitometric ultrasound research, to determine the average acoustic density in different planes taking into account the topographic features of the lens for optimization of the method of phacoemulsification of age cataracts. The use of an improved needle for phacoemulsification reduces the total ultrasonic energy needed to emulsify the lens by 38.5%, which is most effective in patients with a high degree of lens density and reduces the risk of development of postoperative edema of the cornea. Recommendations for the choice of ultrasonic phacoemulsification as an independent method or ultrasonic phacoemulsification in conjunction with a femtosecond laser in patients with age-related cataracts are developed, depending on the degree of lens density. So, in cases with a high degree of density at which using the mathematical model the predicted total energy is determined to be more than 14.1 с.u. it is expedient to conduct phacoemulsification using the improved needle. In cases with a low degree of density, for which the total energy is less than 14.1 c.u., it is necessary to conduct ultrasonic phacoemulsification using a femtosecond laser. The results of the work are implemented in the clinical practice of the Department of glaucoma and pathology of the lens of the State Institution "The Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine", ophthalmologic department №2 of Lviv Rgional Clinical Hospital, ophthalmologic department of Podilsky Central District Hospital, ophthalmologic department of Khust Central District Hospital.
