Diffractive Multifocal Intraocular Lens Research Articles

Impact of posterior vitreous detachment on visual acuity after the implantation of a diffractive multifocal intraocular lens

Purpose: To investigate the effect of posterior vitreous detachment (PVD) on visual acuity (VA) after implantation of a diffractive multifocal intraocular lens (mIOL). Setting: Eye Clinic, Okayama, Japan. Design: Retrospective case series. Methods: This study evaluated 475 eyes of 475 patients who underwent cataract surgery with a TECNIS Multifocal ZLB00 lens implant between November 2017 and October 2019. Patient eyes were classified into the complete PVD group (PVD group) or the control group with no PVD/partial PVD (non-PVD group) and divided into 3 age categories: 65 to 69, 70 to 74, and 75 to 79 years. The postoperative VA of the PVD and non-PVD groups was compared between and within groups by age. Results: Distance-corrected near VA (DCNVA) was significantly worse in the PVD group than in the non-PVD group in all age categories (P ≤ .029). In the PVD group, both corrected distance VA (CDVA) and DCNVA were significantly worse in the 75 to 79 years age group than in the 65 to 69 and 70 to 74 years age groups (P ≤ .034). CDVA and DCNVA in the non-PVD group did not differ significantly between age categories. Conclusions: The results of this study suggest that complete PVD worsens near VA in eyes with a diffractive mIOL. Furthermore, eyes with complete PVD may show an age-related decline in both CDVA and DCNVA. In particular, eyes ≥75 years of age with complete PVD have a poor visual prognosis and should be given careful consideration when deciding whether to implant a diffractive mIOL.

Rotational stability of monofocal and diffractive multifocal toric intraocular lens with identical design and material: a propensity score based prospective comparative study

PurposeTo compare the rotational stability of a monofocal and a diffractive multifocal toric intraocular lens(IOLs) with identical design and material.MethodsThis prospective study enrolled patients who underwent plate-haptic toric IOL (AT TORBI 709 M and AT LISA 909 M) implantation. Propensity score matching (PSM) was performed to balance baseline factors. Follow-up examinations were conducted at 1 h, 1 day, 3 days, 1 week, 2 weeks, 1 month, and 3 months postoperatively. A linear mixed model of repeated measures was used to investigate the changes in IOL rotation over time. A 2-week timeframe was utilized to assess differences in IOL rotation between the two groups.ResultAfter PSM, a total of 126 eyes were selected from each group for further analysis. Postoperatively, the time course of IOL rotation change in the two groups remained consistent, with the greatest rotation occurring between 1 h and 1 day postoperatively. At the 2-week postoperative mark, the monofocal toric IOL exhibited a higher degree of rotation compared to the multifocal toric IOL (5.40 ± 7.77° vs. 3.53 ± 3.54°, P = 0.015). In lens thickness(LT) ≥ 4.5 mm and white-to-white distance(WTW) ≥ 11.6 mm subgroups, the monofocal toric IOL rotated greater than the multifocal toric IOL (P = 0.026 and P = 0.011, respectively).ConclusionThe diffractive multifocal toric IOL exhibits superior rotational stability compared to the monofocal toric IOL, especially in subgroups LT ≥ 4.5 mm and WTW ≥ 11.6 mm. Moreover, the time course of IOL rotation change is consistent for both, with the maximum rotation occurring between 1 h and 1 day postoperatively.

Comparison of the optical behaviour of five different multifocal diffractive intraocular lenses in a model eye

The purpose of this study was to investigate and compare the optical performance of five trifocal intraocular lenses (IOLs) following the ISO 11979-2 standards, analysing the impact of tilt and decentration. Five different diffractive trifocal IOLs were evaluated in this experimental study: Acriva Trinova (VSY-Biotechnology) (AT), FineVision HP (PhysIOL) (FVHP), AT LISA tri 839 MP (Zeiss) (ATLT), PanOptix TFNT00 IOL (Alcon) (PO), and Tecnis Synergy (J&J Vision) (TS). In-vitro optical quality analysis of them was performed with the Lambda PMTF system that has an aberration neutral cornea model (Lambda-X Ophthalmics). Measurements were performed on-axis, with 5º of IOL tilt and with 0.5 mm of IOL decentration using 543-nm monochromatic light. Finally, IOL dimensions and diffractive disk profile inspection was performed using the VisIOLA system (Rotlex). On-axis measurements showed a far through-focus MTF > 0.3 at 3 mm aperture, except for TS. FVHP and PO showed better far MTFs for larger apertures (3.75 mm and 4.5 mm) while AT showed good intermediate and near vision for such apertures. With 5º of IOL tilt, the better optical performance at all distances was found with AT for medium-sized pupils (3 mm) and an important reduction of MTF was found for ATLT and PO, especially in the intermediate focus. The induction of 0.5 mm of IOL decentration especially affected the intermediate focus of ATLT and TS and the far focus of FVHP and PO. IOL dimensions and diffractive profile were consistent with those described by the manufacturer. In conclusion, there are differences in the optical performance according to the pupil aperture of the five trifocal IOLs evaluated and this should be considered in clinical practice when selecting the most appropriate implant in each specific case. IOL tilt and decentration can affect significantly in most of the designs evaluated the performance of the IOL at intermediate vision range. It should be noted that measurements were made with an aberration-free cornea, being necessary future studies analysing the impact of different levels of corneal aberrations.

Multifocal Polypseudophakia With Rayner Sulcoflex Trifocal and In-the-Bag Alcon PanOptix Diffractive Trifocal Intraocular Lenses: A Case Report

Purpose: To describe the use of a sulcus diffractive multifocal intraocular lens (IOL) used in series with an intracapsular diffractive multifocal IOL to improve uncorrected near visual acuity (UNVA). Methods: A 66-year-old pseudophakic woman with bilateral multifocal IOLs presented with symptoms of negative dysphotopsia and poor reading vision in the right eye. A diffractive multifocal sulcus IOL was inserted in the right eye. Results: After 1 month, the patient's right UNVA had improved from N10 to N6. Subjectively there was a 50% improvement in negative dysphotopsia and no increase in photic phenomena. Conclusions: A diffractive trifocal secondary sulcus IOL can be used in series with an intracapsular diffractive trifocal lens. The success of this approach suggests that it may be used to both improve negative dysphotopsia and address postoperative refractive error. [ Journal of Refractive Surgery Case Reports. 2023;3(4):e53–e55.]

Four-flanged polypropylene optic piercing technique for scleral fixation of multifocal intraocular lens

BackgroundTo evaluate the feasibility of creating flanges using an optic piercing technique with a 6 − 0 polypropylene monofilament for scleral fixation of dislocated one-piece diffractive multifocal intraocular lenses (IOLs).Study DesignExperimental study and case series.SubjectsOptical bench test and eyes with IOL dislocation.MethodsTwo separate 6 − 0 polypropylenes were penetrated twice at the opposite peripheral optic of the TECNIS Synergy IOL (Johnson & Johnson Vision). The root mean square of the modulation transfer function (MTFRMS), at between + 1.00 and − 4.00 D of defocus, was measured in the TECNIS Synergy IOL both with and without optic piercing in the optical bench study. This case series included three eyes from two patients who underwent scleral-fixation of multifocal IOLs using the four-flanged polypropylene optic piercing technique. The postoperative corrected distance visual acuity (CDVA) at 4 m, the uncorrected near visual acuity (UNVA) at 40 cm, and IOL centration were evaluated.ResultsThe optical bench test showed no differences in MTFRMS values measured in the TECNIS Synergy IOL, either with or without optic piercing at all defocuses. In all three case series, the postoperative CDVA at 4 m was 20/20 and UNVA at 40 cm was J1. Postoperative anterior segment photographs showed good centration of IOLs in all cases.ConclusionThe four-flanged polypropylene optic piercing technique for multifocal IOL scleral fixation can provide excellent clinical outcomes and IOL stability after surgery without diminishing the performance of the multifocal IOLs.

Clinical Outcomes after Exchange of Diffractive Multifocal Intraocular Lenses with Monofocal Intraocular Lenses

Purpose: To determine the clinical outcomes after exchange of diffractive multifocal intraocular lenses (IOLs) with monofocal IOLs for patients who complained of dysphotopsia after cataract surgery.Methods: We exchanged the IOLs of patients who visited our clinic complaining that dysphotopsia had not improved after they underwent phacoemulsification and diffractive multifocal IOL implants in local eye clinics. We evaluated the corrected distance visual acuity (CDVA) before and after operation, the type of preoperative dysphotopsia, postoperative dysphotopsia status, patient satisfaction, and all complications.Results: We enrolled 35 eyes of 27 patients and observed them for 5.7 ± 3.6 months. After 1 month, the CDVA significantly (<i>p</i> < 0.001) improved from 0.131 ± 0.131 logarithm of the minimal angle resolution (logMAR) preoperatively to 0.0328 ± 0.0900 logMAR postoperatively. Patient satisfaction graded on a scale from 1 (very dissatisfied) to 5 (excellent) significantly (<i>p</i> < 0.001) increased from 1.17 ± 0.382 preoperatively to 4.09 ± 0.818 postoperatively. No vision-threatening complications developed. Postoperative cystoid macular edema developed in one eye but resolved after intravitreal bevacizumab (Avastin<sup>®</sup>, Genetech, Inc, San Francisco, CA, USA) injections.Conclusions: IOL exchange surgery relatively safely improves the vision of patients suffering from dysphotopsia attributable to the characteristics of diffractive multifocal IOLs.

Spatio-chromatic vision with multifocal diffractive intraocular lens

BackgroundThis study aims to detect alterations in the spatio-chromatic pseudophakic vision produced by multifocal diffractive intraocular lenses (IOLs) and provides a physical interpretation.MethodsIn vitro characterization of the imaging performance of two diffractive IOLs: AT LISA Tri (Zeiss) and FineVision (PhysIOL) in on-bench model eye illuminated with red (R, 625 nm), green (G, 530 nm) and blue (B, 455 nm) lights. We used the metrics: energy efficiency (EE), area under the modulation transfer function, longitudinal chromatic aberration (LCA), and halo intensity. Through-focus (TF) analysis and calculation of the expected defocus curve under white (W) daylight were included. In vivo visual acuity (VA) of 50 pseudophakics (60 eyes) was assessed under W, R, G, B lights at far and near. Two clinical experiments evaluated LCA and R, G, B TF-EE effects on pseudophakic vision and their relative importance.ResultsClinical mean VA values under W light agreed with the predicted values at far and near for both IOLs. LCA measurements and R, G, B TF-EE curves were consistent with their lens design based on the 0th and 1st diffraction orders operative for far and near vision, respectively. LCA effects were compensated at near but noticed at far (− 0.75 D under B light). We detected strong asymmetry in visual resolution depending on the object distance and the illuminating wavelength—red predominance at far, blue predominance at near—in consistency with the TF-EE measurements.ConclusionsDiffractive multifocal IOL designs produce asymmetries in the spatio-chromatic vision of pseudophakics beyond the alterations strictly due to LCA. VA asymmetry for far/near object distance under R and B illumination is clinically detectable in subjects implanted with IOLs with 0th and 1st diffraction orders for far and near vision, respectively. Such VA asymmetry cannot be explained solely from the influence of defocus, as would be derived from a chromatic difference of power, but mainly from the wavelength dependence of the EE.

Assessment of Visual Habituation Measured With the Halo & Glare Simulator and Its Impact on Patient Satisfaction Following Quadrifocal IOL Implantation.

To evaluate the levels of habituation and its influence on outcome satisfaction in patients who underwent bilateral multifocal intraocular lens (IOL) implantation. A total of 24 patients underwent bilateral multifocal IOL implantation surgery with the AcrySof IQ PanOptix trifocal diffractive IOL (Alcon Laboratories, Inc) following cataract extraction or for refractive purposes. Data were collected 3 and 6 months after surgery, which included subjective refraction, corrected and uncorrected visual acuity (distance, intermediate, near), a contrast sensitivity test, simulation with the Halo & Glare Simulator (Carl Zeiss Meditec AG), two visual quality surveys, and a slit-lamp examination by an ophthalmologist. All patients were spectacle independent for distance vision and 92% (n = 22) needed no visual aid for near vision. Minor visual acuity improvement was detected between both examinations at monocular uncorrected distance visual acuity (P = .025). Improvements of presence, size, and intensity of visual disturbances were not statistically significant, but overall patient satisfaction (P = .009) and Weber-Contrast sensitivity under mesopic conditions (P = .029) increased significantly. Diffractive multifocal IOLs are a stable treatment for presbyopia and/or cataract with a high spectacle independence rate. Visual disturbances caused by their optics do not decrease significantly between 3 and 6 months after surgery. Habituation and neuroadaptation play a significant role in patient satisfaction and contrast sensitivity during and possibly beyond that period. [J Refract Surg. 2023;39(8):510-517.].

Comparison of the Polychromatic Image Quality of Two Refractive-Segmented and Two Diffractive Multifocal Intraocular Lenses.

Evaluating chromatic aberration for a multifocal intraocular lens (MIOL) in vitro is essential for studying its performance because it helps determine the most appropriate lens for each patient, enhancing surgical outcomes. While refractive MIOLs with angular power variation have shown positive clinical outcomes, studies of these MIOLs on optical benches primarily employed monochromatic green light, neglecting the impact of longitudinal chromatic aberration (LCA) on MIOL performance. To address this gap, we evaluated the through-focus modulation transfer function (TF-MTF) and the point spread function (PSF) of two refractive segmented extended depth of focus intraocular lenses (IOLs) (Femtis Comfort and Precizon Presbyopic), comparing the results with those obtained with two widely known diffractive multifocal intraocular lenses (AcrySof IQ ReSTOR and FineVision Pod F). Measurements of the TF-MTF were conducted using both monochromatic and polychromatic light in a customized optical bench. The refractive designs exhibited distinct haloes in the PSFs. When comparing the refractive and diffractive designs, opposite signs of LCA were observed at near foci. These findings emphasize the influence of the optical design of IOLs on their performance under polychromatic light, providing valuable information for vision care professionals when selecting the most suitable lens for each patient.

Effect of Multifocal Intraocular Lens on Contrast Sensitivity in Primary Angle-Closure Patients

Objective: To study the effect of multifocal intraocular lens (MIOL) implantation on contrast sensitivity (CS) compared to monofocal intraocular lens (mIOL) in primary angle-closure (PAC) or primary angle-closure glaucoma (PACG) patients. Materials and Methods: This prospective study included patients with PAC or PACG and visually significant cataract. Phacoemulsification with MIOL or mIOL (patient preference) was performed. Collected data included best-corrected distant visual acuity (BCVA), intraocular pressure (IOP), anterior chamber depth (ACD), and contrast sensitivity (CS) measured at spatial frequency 1.5, 3.0, 6.0, 12.0, and 18.0 cycles per degree (CPD) preoperatively, and at 2-6 months postoperatively. Preoperative and postoperative parameters were then compared.   Results: Of the 45 eyes from 35 patients that were enrolled, 33 eyes (15 PAC, 18 PACG) from 26 patients completed the study. Fourteen eyes (11 patients) received diffractive MIOL, and 19 eyes (15 patients) received aspheric mIOL. Preoperative CS was not significantly different between groups. Postoperatively, BCVA, and CS at each spatial frequency were significantly improved in both groups (all p<0.001). Mean postoperative CS at spatial frequency 1.5, 3.0, 6.0, 12.0, and 18.0 CPD was 28.03, 42.63, 44.84, 10.82, and 2.86 in the MIOL group, and 29.55, 49.63, 46.20, 16.83, and 7.09 in the mIOL group, both respectively. Postoperative CS was not significant different between groups at any spatial frequencies. IOP was decreased (p=0.001) and ACD increased (p<0.001) postoperatively in both groups. Conclusion: No significant difference in visual acuity or contrast sensitivity was observed between MIOL and mIOL after cataract removal in patients with PAC/PACG.

Recommendation for Presbyopia-Correcting Intraocular Lenses: A Delphi Consensus Statement by the ESASO Study Group

To establish consensus among experts in lens and refractive surgery to guide general ophthalmologists on issues related to presbyopia-correcting intraocular lenses (IOLs). A modified Delphi method to reach a consensus among experts. A steering committee formulated 105 relevant items grouped into four sections (preoperative considerations, IOL selection, intraoperative considerations, and postoperative considerations). The consensus was defined as ≥ 70% of experts agreeing with the evaluation of a statement. Ten experts participated and completed all rounds of questionnaires (100% response rate). Of 68 items considered in the preoperative considerations, consensus was achieved in 48 (70.6%). There was a lack of consensus over IOL selection, the experts only agreed on the importance of the patient's habits for the optical IOL design selection. Of the 14 considerations related to intraoperative issues, the experts reached a consensus on 10 (71.4%). The postoperative considerations section reached the highest consensus in 10 items of 13 (76.9%). Key recommendations for a diffractive multifocal IOL were a potential postoperative visual acuity > 0.5, a keratometry between 40-45 diopters, a pupil >2.8mm under photopic conditions and <6.0 mm under scotopic conditions, a root mean square of higher order corneal aberrations <0.5 µm for 6-mm pupil size, while monofocal or non-diffractive IOLs should be considered for patients with coexisting eye disorders. A lack of agreement was found in the issues related to the IOL selection.

Visual performance and rotational stability of a multifocal toric intraocular lens in myopic eyes.

This study aimed to evaluate the visual performance and rotational stability of the multifocal toric intraocular lens in myopes. This prospective, observational study included patients with an axial length of ≥24.5 mm and regular corneal astigmatism of >1 diopter who underwent phacoemulsification cataract surgery and implantation of a multifocal toric intraocular lens (AT LISA toric 909M). The visual acuity, defocus curves, residual astigmatism, rotational stability, higher-order aberrations (HOAs), modulation transfer function (MTF), spectacle dependence and patient satisfaction were evaluated 3 months after surgery. Forty-three eyes from 30 patients were enrolled in this study. Postoperatively, uncorrected distance and near visual acuities (logMAR) were 0.09 ± 0.08 (standard deviation, SD) and 0.14 ± 0.08, respectively. The defocus curve analysis provided a bimodal curve showing two peaks of maximum vision at 0.0 D and at -3.0 D defocus level. The multifocal toric intraocular lens showed excellent rotational stability; the mean rotation was 4.02 ± 2.49 (SD) degrees at 3 months postoperatively. Refractive predictability was excellent with a mean spherical equivalent of 0.19 ± 0.37 (SD) diopters (D) and a mean refractive cylinder of -0.34 ± 0.39 (SD) D. The diffractive multifocal toric intraocular lens, AT LISA toric 909M, provided effective distance and near visual acuities in myopic eyes. It was a predictable and effective device with good rotational stability for the correction of preexisting astigmatism during cataract surgery. In this study, more than 80% of patients achieved spectacle independence.

Pitfalls of Using NIR-Based Clinical Instruments to Test Eyes Implanted with Diffractive Intraocular Lenses

The strong wavelength dependency of diffractive elements casts reasonable doubts on the reliability of near-infrared- (NIR)-based clinical instruments, such as aberrometers and double-pass systems, for assessing, post-surgery, the visual quality of eyes implanted with diffractive multifocal intraocular lenses (DMIOLs). The results obtained for such patients when using NIR light can be misleading. Ordinary compensation for the refractive error bound to chromatic aberration is not enough because it only considers the best focus shift but does not take into account the distribution of light energy among the foci which strongly depends on the wavelength-dependent energy efficiency of the diffractive orders used in the DMIOL design. In this paper, we consider three commercial DMIOL designs with the far focus falling within the range of (-1, 0, +1)-diffractive orders. We prove theoretically the differences existing in the physical performance of the studied lenses when using either the design wavelength in the visible spectrum or a NIR wavelength (780 to 850 nm). Based on numerical simulation and on-bench experimental results, we show that such differences cannot be neglected and may affect all the foci of a DMIOL, including the far focus.

The Effect of Psychological Intervention on the Visual Quality of Patients with a Diffractive Multifocal Intraocular Lens Implant.

This study aimed to investigate the effect of psychological intervention on the visual quality of patients with a diffractive multifocal intraocular lens implant and its possible mechanism. Eighty-nine patients undergoing age-related cataract surgery were enrolled in the study at the Affiliated Hospital of Southwest Medical University between December 2015 and July 2017. They were randomly divided into two groups: multiple focus M1 group (n = 45) and multiple focus M2 group (n = 40). The M1 group was only given routine preoperative health education, treatment, and evaluation, while the M2 group also received psychological intervention. After treatment, there was no statistical difference in the uncorrected distance and near visual acuity, corrected distance and near visual acuity, or the vision and near removal rate in either of the two groups (p > 0.05). However, postoperative glare was lower in the M2 group (p < 0.05), and patient satisfaction was higher in the M2 group (p < 0.05). The M2 group had a more obvious improvement in the Symptom Checklist-90 score (p < 0.05), the serum interleukin-6 (IL-6) was lower, and the serum brain-derived neurotrophic factor (BDNF) was higher in the M2 group (p < 0.05). In addition, serum IL-6 had a negative correlation with the depression score, and serum BDNF also showed a negative correlation with the anxiety score (p < 0.05). Psychological intervention improved the stress state of patients with age-related cataracts and diffractive multifocal intraocular lens implants, reduced the level of inflammatory factors in the body, improved the level of BDNF, reduced postoperative visual interference, and improved postoperative satisfaction.

Visual satisfaction and spectacle independence with monofocal intraocular lens with enhanced intermediate vision and trifocal intraocular lenses in the prepresbyopic age group patients with cataracts.

This aims to study visual satisfaction and spectacle independence in prepresbyopic age patients with cataracts after the implantation of either monofocal intraocular lens (IOL) with enhanced intermediate vision or trifocal IOL. Private practice. This prospective, observational case study was conducted on patients in the prepresbyopic age group with cataracts. Patients were allocated to one of the two groups. Thirteen patients (26 eyes) received monofocal IOL with enhanced intermediate vision (intermediate vision group), and 12 patients (24 eyes) received diffractive multifocal IOLs (trifocal group). Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity, Uncorrected intermediate visual acuity (UIVA) and uncorrected near visual acuity (UNVA) values, defocus curves, and contrast sensitivities (CS) of the two groups were compared 3 months' postsurgery. Their spectacle independence and visual satisfaction were also assessed. The study patients were aged 35-45 years and comprised 14 males and 11 females. No significant difference was observed in UDVA (intermediate vision group: 0.02 ± 0.01, trifocal group: 0.02 ± 0.01; P = 0.22) and UIVA (intermediate vision group: 0.20 ± 0.10, trifocal group: 0.19 ± 0.10; P = 0.12). However, a statistically significant difference was observed between the groups in terms of UNVA (intermediate vision group: 0.32 ± 0.10, trifocal group: 0.80 ± 0.10; P = 0.01). The mean CS in monofocal IOL with enhanced intermediate vision and trifocal groups were 1.577 ± 0.3 and 1.550 ± 0.2, respectively (P = 0.40). None of the patients experienced photic phenomena. In total, 10 of 13 patients in the monofocal IOL with enhanced intermediate vision group required spectacle correction for near visual acuity in the range of +1.00 to +2.00 D. This study found that there was no significant difference in distance and intermediate vision between the two groups. However, the trifocal group had better uncorrected near vision compared to the monofocal group that had enhanced intermediate vision. The conclusion is that using trifocal IOLs for both eyes provided complete independence from wearing glasses. In addition, no visual disturbances were observed after implanting the new-generation trifocal IOLs.

Design and Optimization of Diffractive Multifocal Intraocular Lenses

Design and Optimization of Diffractive Multifocal Intraocular Lenses

Comparative Visual Outcome Analysis of a Diffractive Multifocal Intraocular Lens and a New Diffractive Multifocal Lens with Extended Depth of Focus.

This study compares the visual and refractive performance of the TECNIS Synergy (DFR00V-DFW150-225-300-375) multifocal intraocular lens (IOL) and the AcrySof IQ PanOptix (TFAT00-30-40-50-60) multifocal IOL. Patients who underwent phacoemulsification and cataract extraction and received either a multifocal Synergy or PanOptix IOL were included. Monocular uncorrected distance (UDVA), intermediate (UIVA), near (UNVA), and corrected distance (CDVA) visual acuities were assessed at three and six months postoperatively. Secondary outcome measures of photic phenomena were also assessed. A total of 140 patients (224 eyes) were included in this study, with 69 patients (105 eyes) in the Synergy group and 71 patients (119 eyes) in the PanOptix group. There were no statistically significant differences in UIVA or CDVA measurements across all time points. When assessing UDVA, at three months postoperatively, there were more eyes in the PanOptix group with vision better than 20/40 (p = 0.04). At three and six months postoperatively, the average UNVA was superior in the Synergy group (p = 0.01, 0.002). While the Synergy group reported more night vision disturbances at one and three months (p = 0.01, 0.03), the PanOptix group had more night vision disturbances at six months (p = 0.02). Although not statistically significant, the AcrySof IQ PanOptix multifocal IOL demonstrated better UDVA and UIVA sooner postoperatively than the TECNIS Synergy multifocal IOL. The Synergy IOL provided statistically better UNVA compared to the PanOptix IOL at three and six months postoperatively. Synergy patients reported more early photic phenomena than PanOptix patients, which later diminished.

Problems with diffractive IOLs

AbstractIn 2015, it was estimated that approximately 1.8 billion people were affected by presbyopia globally which was about 25% of the world population, and approximately 826 million people lacked proper visual correction. In the year 2030, the number of people with presbyopia is expected to be increasing to 2.1 billion people globally. two major IOL.Treatment and correction of presbyopia have become challenging with increasing demands and expectations of patients since there are no drugs or procedures that can cause perfect vision at all distances without risk. Surgical options, corneal or intraocular, are of increasing interest since they are based on most modern technologies. There are still risks of surgical complications, which are hardly reversible, and the best results are based on careful selection of patients. Moreover, good understanding of the limitation of the present technologies by patients and their trade‐off nature are very important, for example, patients who gain spectacle‐free of near or intermediate vision may experience some dysphotopsias in different lighting conditions or lose some sharpness of vision or stereopsis depending on the offered technology. Multifocal IOLs (MIOLs) can be made using refractive and diffractive surfaces or combination of both. The optical power in the refractive design decreases continuously from the center to the periphery of the lens creating an infinite number of focal points and is derived from the smooth hyperbolic shape of its optics. Thus, the performance of refractive design IOLs is dependent on pupil size and IOL centration. On the other hand, a diffractive IOL generates multifocality making use of light interference and is independent of pupil size. It incorporates a pattern consisting of a series of annular concentric grooves less than one micron in depth, which are engraved around the optical axis on either the front or the back surface of a lens (the echelette technology). One of the recent studies from Japan reported that patients implanted with diffractive multifocal IOLs had notable declines in the corrected distance visual acuity, distance corrected near VA, and near area of focus with aging.When compared to monofocal IOLs, MIOLs will always be related with poorer quality of vision. Moreover, good understanding of the limitation of the present technologies by patients and their trade‐off nature are very important, for example, patients who gain spectacle‐free of near or intermediate vision may experience some dysphotopsias in different lighting conditions or lose some sharpness of vision or stereopsis depending on the offered technology. Halos, glare, reduced contrast sensitivity or reduced retinal illumination are relatively common problems with MIOLs. Halos depend on the intensity and size of the out‐of‐focus image corresponding to the other foci produced by the lens, that is secondary to add power and energy distribution among foci. Moreover, if aberrations are used in their design, their position and centering might be crucial. MIOLs do not replicate the natural condition, thus patients with MIOLs must learn and adapt to their use with so called binocular neuro‐adaptation.

Visual outcomes of epiretinal membrane removal after diffractive-type multifocal intraocular lens implantation

BackgroundTo assess visual outcomes of epiretinal membrane (ERM) removal in multifocal intraocular lens (MIOL)-implanted eyes, according to ERM stage.MethodsRetrospective chart reviews were undertaken in patients with diffractive-type MIOL implants, each undergoing pars plana vitrectomy and ERM removal between February 2018 and November 2020 at Gyeongju St. Mary's Eye Clinic and KEYE Eye Center. Assessments focused on monocular uncorrected and corrected values of distant visual acuity (UDVA and CDVA) and uncorrected near visual acuity (UNVA) at postoperative 12 months according to the stage of ERM.ResultsThe present study included a total of 49 MIOL-implanted eyes from 49 enrollees, 25 undergoing pars plana vitrectomy for ERM removal (11 eyes with Stage 2 and 14 eyes with Stage 3), and 24 acting as age-matched controls. There was a significant difference in UDVA and UNVA between control and Stage 3 ERM (UDVA; 0.01 ± 0.04 for control, and 0.07 ± 0.08 for stage 3 ERM, p = 0.035, UNVA; 0.03 ± 0.05 for control, and 0.13 ± 0.16 for Stage 3 ERM, p = 0.029). There were no significant differences in CDVA between groups (p = 0.121, ANOVA test).ConclusionsEyes with Stage 3 ERM did not achieve visual acuity comparable to control eyes, suggesting the necessity of an early intervention for ERM in eyes with diffractive type MIOL. A meticulous preoperative retinal evaluation for ERM development is mandatory when planning diffractive-type MIOL implantation.

Clinical outcomes of new multifocal intraocular lenses with hydroxyethyl methacrylate and comparative results of contrast sensitivity, objective scatter, and subjective photic phenomena

BackgroundWe investigate the performance of new hydrophobic diffractive multifocal intraocular lenses (IOL) with hydroxyethyl methacrylate (HEMA) and compare their optical quality, contrast sensitivity, and subjective photic phenomena.MethodsMedical records of patients who underwent routine simple cataract surgery and insertion of an existing multifocal IOL (TFNT, TF group) or a new multifocal IOL (CNWT, CN group) were retrospectively reviewed. Clinical data was collected 2 months postoperatively and included optical quality analysis system (OQAS) indices, contrast sensitivity, and subjective degrees of photic phenomena.ResultsOne hundred thirty-five eyes of 135 patients were included (CN group, 71; TF group, 64). There was no significant difference between the two groups in the visual acuity and defocus curve. The indices of OQAS did not show a significant difference between groups. Contrast sensitivity was significantly better in the CN group at all degrees, including the area under the log contrast sensitivity function (p = 0.01). The subjective photic phenomena survey showed better results for the CN group, with the proportion of patients reporting no photic phenomena as 9.9% and 3.1% in the CN and TF groups, respectively. The proportion of patients who reported severe photic phenomena was 11.3% in the CN group and 25.0% in the TF group. Although the follow-up period was only 2 months, glistening, surface scattering, and posterior capsule opacity were not observed in any patient.ConclusionsThe new multifocal IOL with HEMA is safe, and provides stable visual acuity as well as superior contrast sensitivity and lower subjective photic phenomena, over the prior IOL.