Calculation of IOL in combined surgery: cataract phacoemulsification and vitrectomy. Own experience

At the present stage of development of ophthalmic surgical technique, indications for simultaneous cataract phacoemulsification and pars plana vitrectomy are constantly expanding, however, there is a problem of predicting refractive results, which is due to the difficulty of determining the effective position of the intraocular lens (IOL) in the eye without the presence of a vitreous body. Purpose. Assessment of the accuracy of the preoperative calculation of IOL in the eyes during combined surgery — cataract phacoemulsification and vitrectomy on the state of postoperative refraction. Material and methods. Combined surgery of cataract phacoemulsification and vitrectomy of pars plana with a caliber of 25 Gage was performed in 51 people (51 eyes) aged 70.4 ± 8.4 years. The calculation of IOL before surgery was carried out according to the data of a preoperative examination on an optical biometer IOL-Master-700 (Carl Zeiss, Germany), keratopography was performed on a rotary Scheimpflug camera (Oculus, Germany). The data on SRK-T with a range of more than 22.5 mm and Hoffer-Q with a range of less than 22.5 mm were used as a basis. Results. There were no complications during the operations and in the postoperative period. Preoperative uncorrected visual acuity (UCVA) was 0.21 ± 0.2 (0.05 to 0.8) and the best-corrected visual acuity (BCVA) was 0.44 ± 0.22 (from 0.1 to 0.9). The correction is from –9.0 D to +7.75 D (–0.61 ± 2.71 D). 6 months after the operation, the UCVA was 0.67 ± 0.22 (from 0.05 to 1.0), the BCVA was 0.9 ± 0.2 (from 0.3 to 1.0), respectively, while the correction was from –1.25 D to +1.0 D (–0.17 ± 0.94 D). The deviation from the expected refraction of the target at 1 week after surgery was ± 0.5 D, at 6 months after surgery ± 0.4 D, which turned out to be statistically insignificant (p > 0.05). Conclusions. 1. Combined surgery phacoemulsification and vitrectomy in combination of cataracts with pathology of the vitreomacular interface, significantly increases visual acuity after surgery (by 0.43 ± 0.03, p < 0.001). 2. Changes in clinical refraction during implantation of IOL based on hydrophobic acrylic in combined surgery are not statistically significant (an average shift of ± 0,4–0,5 D, p > 0.05), which allows us to apply generally accepted formulas for calculating the effective position of IOL without using correction factors.