Correction of Astigmatism by a Single-Focus Toric Intraocular Lens during Cataract Surgery: Refractive State and Visual Acuity

Purpose: the main purpose of study is to obtain a better visual outcome after implantation of a monofocal toric IOLs by accurate measurement, calculations and visual assessment.Methods. Fifty eyes with astigmatism of more than 2.5 D were included in a hospital-based prospective study. A biometric evaluation is done by Lenstar. Barette's toric calculation method is used to measure toric IOLs power. In a vertical position, preoperative axis marking was done by both bubble marker and direct slit beam. On table, in a horizontal position, axis marking was reassessed. After phacoemulsification, a monofocal Supra Phob toric IOL was implanted and rotated to match corneal axis marking. Best-corrected visual acuity was measured postoperatively at 1 and 3 months.Results. Reduction of mean of refractive astigmatism was reported postoperatively from 4.0 ± 0.79 preoperatively to 0.7 ± 0.28 at 1 month and 0.6 ± 0.27 at 3 months postoperatively. In whole, 96 % has residual astigmatism less than 1 D at 3 months postoperatively, while 8 % eyes had residual astigmatism more than 1 D. In whole, 76 % patients had IOLs rotation of less than or equal to 5°, 20 % patients had it between 6° and 10° and 4 % eyes had more than 10° at day 7 postoperatively, in which repositioning of IOLs was required.Conclusion. To reduce postoperative residual astigmatism after toric IOLs and to get better results, accurate measurement of parameters and proper calculation are essential.

Comparison of trifocal toric and bifocal toric intraocular lens implantation in patients with cataract and high corneal astigmatism

AIM: To investigate and compare the quality of life, satisfaction, contrast sensitivity, glare, depth perception, and intraocular lens (IOL) rotation in patients who underwent trifocal toric and bifocal toric IOLs. METHODS: A total of 80 eyes of 40 patients were included in this prospective study. Twenty patients in each group were implanted with trifocal toric and bifocal toric IOL, respectively. Preoperative and postoperative 6-month measurements were recorded for both patient groups. Comprehensive anterior and posterior segment examinations, distance-intermediate-near visual acuity values and the visual function scale questionnaire results were evaluated at these examinations. Patient satisfaction, contrast sensitivity, glare, intermediate-near and distance stereopsis and IOL rotation were also evaluated. RESULTS: No significant difference was found between the groups in terms of distance and near visual acuities (P=0.269, P=0.451). Intermediate visual acuity was significantly increased in the trifocal toric group (P<0.001). The visual function scale results were increased after surgery in both groups (P=0.001 and P<0.001), with no difference determined between them (P=0.158 and P=0.691). The number of patients wearing glasses was low in both groups and there was no significant difference between the groups (P>0.05). The overall satisfaction in the trifocal toric group was significantly higher than in the bifocal toric group (P=0.03). The highest sensitivity was observed at 6 cpd spatial frequency in all patients under photopic conditions (1.80±0.24 logU, 1.74±0.20 logU). Distance-intermediate-near binocular depth perception results in both groups were higher in the trifocal toric group (P=0.02, 0.048, 0.003, respectively). Although there was no significant difference for 3 meters stereopsis, the trifocal toric group had higher depth perception (P=0.577). Mean rotation was 5.76°±3.93° in the trifocal toric group and 12°±7.1° in the bifocal toric group. CONCLUSION: Better results in the middle distance are obtained in the trifocal toric group and less IOL rotation due to digital system-coordinated surgery. Moreover, the overall satisfaction in the trifocal toric group is significantly higher than in the bifocal toric group.

Automatic detection of pupil reactions in cataract surgery videos

In the light of an increased use of premium intraocular lenses (IOL), such as EDOF IOLs, multifocal IOLs or toric IOLs even minor intraoperative complications such as decentrations or an IOL tilt, will hamper the visual performance of these IOLs. Thus, the post-operative analysis of cataract surgeries to detect even minor intraoperative deviations that might explain a lack of a post-operative success becomes more and more important. Up-to-now surgical videos are evaluated by just looking at a very limited number of intraoperative data sets, or as done in studies evaluating the pupil changes that occur during surgeries, in a small number intraoperative picture only. A continuous measurement of pupil changes over the whole surgery, that would achieve clinically more relevant data, has not yet been described. Therefore, the automatic retrieval of such events may be a great support for a post-operative analysis. This would be especially true if large data files could be evaluated automatically. In this work, we automatically detect pupil reactions in cataract surgery videos. We employ a Mask R-CNN architecture as a segmentation algorithm to segment the pupil and iris with pixel-based accuracy and then track their sizes across the entire video. We can detect pupil reactions with a harmonic mean (H) of Recall, Precision, and Ground Truth Coverage Rate (GTCR) of 60.9% and average prediction length (PL) of 18.93 seconds. However, we consider the best configuration for practical use the one with the H value of 59.4% and PL of 10.2 seconds, which is much shorter. We further investigate the generalization ability of this method on a slightly different dataset without retraining the model. In this evaluation, we achieve the H value of 49.3% with the PL of 18.15 seconds.

Analys of multifocal and toric extended depth of focus intraocular lenses implantation

Purpose. Analysis of the functional results of new IOL with an extended depth of focus implantation a in the short-term (6 months) follow-up period. Material and methods. The prospective study included 27 patients (40 eyes) after bilateral (n=12) or monolateral (n=15) implantation of EDOF IOL Tecnis Symfony with an average follow-up period of 6.5±0.2 (6-7) months. In all cases, IOL implantation was preceded by cataract phacoemulsification or removal of the transparent lens for refractive purposes. The age range was from 39 to 78 (60.6±10.1) years. EDOF IOL Tecnis Symfony ZXR00 was implanted in 30 eyes, and toric EDOF IOL Tecnis Symfony ZXT100, ZXT150, ZTX225, and ZXT300 were implanted in 10 eyes in the presence of clinically significant astigmatism. Results. An increase in UCNVA from 0.18±0.04 to 0.79±0.11, UCIVA from 0.21±0.07 to 0.89±0.10, UCDVA from 0.24±0.06 to 0.95±0.16, BCNVA from 0.61±0.05 to 0.80±0.03, BCIVA from 0.58±0.10 to 0.97±0.19, and BCDVA from 0.65±0.08 to 1.0±0.06 (p<0.05 in all cases). The spherical equivalent of refraction decreased from -4.5±1.8 in the preoperative period to -0.18±0.92 in the follow-up period of 6 months after implantation of the Tecnis Symfony ZXR00 IOL. In the group with toric IOLs, a decrease in the cylindrical component of refraction was shown from 1.33±1.02 (modulo) to 0.61±0.44 (modulo) during the maximum observation period. In all cases, the rotational stability of the implanted IOLs was noted. In 9 patients out of 24 (37.5%), permanent or periodic optical phenomena were detected, of which 4 patients (16.7%) had halos, 3 (12.5%) had glare, and 2 (8.3%) had difficulty driving in the dark. These side effects did not affect the overall patient satisfaction – 22 patients (91.7%) rated the result of the operation as "excellent", and 2 patients (8.3%) – as "good". Conclusion. The paper presents an analysis of the first experience in the Russian Federation of implantation of new multifocal and toric IOLs with extended depth of focus in 27 patients. Data on the effectiveness of this IOL for vision correction at all distances, low frequency of side optical phenomena, and high patient satisfaction are presented. Further comparative studies with other multifocal IOLs are needed. Key words: cataract; presbyopia; multifocal IOL; IOL with extended depth of focus; EDOF; Symphony.

Changes of anthropometric parameters of an eye during the implantation of toric intraocular lenses in children with congenital cataracts.

Aim. The aim of the study is to examine changes in the anthropometric and refractive parameters of the eyeball in children with congenital cataracts who have been implanted with various types of IOLs (toric or classic monofocal). Materials and methods. In this work, we retrospectively studied the medical history of 34 children (42 eyes) aged 4 to 15 years, who underwent phacoemulsification of congenital cataracts with implantation of various types of IOLs: toric and simple monofocal. Further, in these groups, by statistical methods, the dynamics of refraction in the first three years after the operation, the incidence of postoperative astigmatism, and its dynamics were assessed. We also assessed the rate of change in the anteroposterior axis of the eyeball, the dynamics of refraction in terms of the total spheroequivalent and maximum visual acuity in 3 years after the operation. Results. According to the results of the study, it was shown that toric IOLs significantly better stimulate the process of emmetropization of the eyeball, and also have a significant tendency to completely eliminate postoperative astigmatism, within 3 years after surgery. However, there were no significant differences in maximally corrected visual acuity between the 2 compared groups. There were also no data showing a significant difference in the more frequent development of myopia in the group receiving the toric IOL. Conclusion. The correct choice and calculation of the IOL remains one of the most difficult tasks in pediatric cataract surgery. New technologies are introduced annually and require constant testing. In this study, we have shown the possibility of using toric IOLs and their positive effects in pediatric cataract surgery and in the prevention and treatment of obscuration amblyopia. Key words: pediatric cataract, intraocular lenses, myopia, refraction, phacoemulsification, amblyopia.