Aspheric Intraocular Lens Research Articles

Analysis of higher-order aberrations in relation to the clinical outcome of an enhanced monofocal IOL.

To analyse higher-order aberrations of an enhanced monofocal aspheric intraocular lens (IOL) in relation to the clinical outcome compared to a monofocal aspheric IOL. Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Germany. Prospective, monocentric, controlled, non-randomized, two-armed study. After phacoemulsification, a total of 30 patients (60 eyes) were bilaterally implanted with either TECNIS Eyhance IOL model ICB00 (Johnson & Johnson Surgical Vision, Inc.) or TECNIS Monofocal 1-Piece IOL model ZCB00 (Johnson & Johnson Surgical Vision, Inc.) in 30 eyes each. Assessments were performed 1 and 3 months after surgery including refraction, uncorrected and best-corrected distance, intermediate and near visual acuity, defocus curves, contrast sensitivities under photopic, mesopic and mesopic conditions with glare, higher-order aberrations (HOAs) at pupil sizes of 5, 4, 3 and 2 mm and patient satisfaction. At 3-month follow-up, measurements of HOAs revealed significant higher negative internal and ocular primary spherical aberrations in the ICB00 group at pupil sizes of 5, 4, 3 and 2 mm. The ICB00 showed significant better results in intermediate and near visual acuity, but no difference in distance visual acuity. No significant difference was found in contrast sensitivities at any condition or spatial frequency. Spectacle independence was significant better without significant higher rates of dysphotopsia in the ICB00 group. Higher negative spherical aberrations in the ICB00 group at all measured pupil sizes appear to lead to a superior clinical outcome in intermediate and near vision compared to the ZCB00 group without compromising contrast sensitivity or distance visual acuity.

Evaluation of macular visibility through a high-order aspheric intraocular lens using a simulated model eye.

We evaluated the macular visibility of a newly designed extended depth of focus (EDOF) intraocular lenses (IOL) using a wide viewing system for macular manipulation (Risight;60D, Carl Zeiss Meditec AG) in a model eye and compared it with various other types of IOLs. We used a model eye that was constructed based on the Glustrand model to compare a newly designed EDOF IOL (DIB00V; Johnson & Johnson Surgical Vision), an EDOF IOL with a diffraction grating (ZXR00V; Johnson & Johnson surgical Vision), and a monofocal aspheric (DCB00V; Johnson & Johnson Vision, XY-1; HOYA Surgical Optics, Tokyo, Japan) or spherical IOL (NX70s; Santen Pharmaceutical Co., Ltd). In the model eye, a 1951 United States Air Force (USAF) test was placed at the location of the macula. The contrasts in a range of spatial frequencies were quantified using the images obtained from the 1951 USAF test target. The contrast at each spatial frequency was plotted and integrated to calculate the area under the curve contrast (AUC-contrast). Qualitative evaluations showed that good-quality images were obtained for all IOLs. At a spatial frequency of 16 LP/mm, the average contrast was the highest for the DIB00V and NX70s (0.216 each). The highest average contrast at 32 LP/mm was obtained using the NX70s (0.128), and at 64 LP/mm using the DIB00V (0.123). The horizontal AUC-contrast was the highest for the NX70s (8.754), and the vertical AUC-contrast was the highest for the DIB00V (8.334). On average, the DIB00V had the highest AUC-contrast value (8.227). The high-order aspheric IOL, DIB00V, was found to exhibit good macular visibility despite being an EDOF IOL.

Comparison of two one-piece acrylic foldable intraocular lenses: Short-term change in axial movement after cataract surgery and its effect on refraction.

To compare the change in intraocular lens (IOL) axial movement, corneal power, and postoperative refraction of eyes implanted with two different single-piece, open loop, acrylic foldable IOLs with planar-haptic design: one IOL with hinges vs. one IOL without hinges. The role of IOL axial movement on short-term refractive shift after cataract surgery was also evaluated. This retrospective comparative study enrolled consecutive patients who had phacoemulsification with aspheric IOL implantation. The IOL depth (the distance from corneal endothelium to IOL surface) and corneal power were measured via anterior-segment optical coherence tomography at 4 days and 1 month postoperatively. The changes in axial movement of the IOL, corneal power, and manifest refractive spherical equivalent (MRSE) were compared among groups, and the correlations between each lens were evaluated. IOL with hinges was implanted in 42 eyes of 42 patients and IOL without hinges was implanted in 42 eyes of 42 patients. The change in axial movement between 4 days and 1 month was significantly smaller in the IOL with hinges group than in the IOL without hinges group (p < 0.001). The axial movement of IOL with hinges did not correlate with the MRSE change; however, the forward shift of IOL without hinges correlated with the myopic refractive change (Pearson r = 0.62, p < 0.001). The postoperative axial movement of IOL was more stable in the IOL with hinges group than the IOL without hinges group between 4 days and 1 month after cataract surgery. Even though the two study IOLs with planar-haptic design are made of similar acrylic materials, other characteristics such as hinge structure may affect IOL stability in the bag.

Influence of decentration and tilt of Tecnis ZCB00 on visual acuity and higher order aberrations.

To determine the influence of decentration and tilt of a pseudophakic aspheric intraocular lens (IOL) on visual acuity (VA) and higher-order aberrations (HOAs), and to analyze the agreement between pupil center/axis and iridocorneal angles center/axis when assessing IOL decentration and tilt. A prospective interventional case series study including thirty-three patients undergoing Tecnis ZCB00 (Abbott Medical Optics) implantation. IOL decentration and tilt with respect to two reference systems (pupil and iridocorneal angles centers/axes), in cartesian (X,Y) and polar (radius/tilt, polar angle/azimuth) coordinates, were assessed with optical coherence tomography. VA and internal and ocular HOAs were evaluated. Multiple linear regression models and intraclass correlation coefficient (ICC) were computed. IOL decentration only showed a significant effect on internal HOAs for [Formula: see text] (R2 = 0.20, P = 0.04). IOL decentration with respect to the pupil center showed a significant effect on ocular [Formula: see text] (R2 = 0.18, P = 0.05), [Formula: see text] (R2 = 0.36, P = 0.001) and [Formula: see text] (R2 = 0.24, P = 0.02); and with respect to the center of iridocorneal angles, on ocular [Formula: see text] (R2 = 0.21, P = 0.03), [Formula: see text] (R2 = 0.32, P = 0.003), primary coma (R2 = 0.41, P < 0.001), and coma-like (R2 = 0.40, P = 0.001). Poor agreement between both reference systems was found for IOL decentration measurements (ICC ≤ 0.41), except for the polar angle coordinate (ICC = 0.83). Tilt measurements showed good agreement (ICC ≥ 0.75). Tecnis ZCB00 decentration and tilt values after uneventful implantation appear not to have influence on VA, and their effect on HOAs are not high enough to clinically affect quality of vision. Pupil and iridocorneal angles used as reference systems may be interchangeable for IOL tilt measurements, but not for decentration.

Refractive and Visual Outcomes of a Monofocal Non-Constant Aberration Aspheric Intraocular Lens.

PurposeTo evaluate the refractive and visual outcomes following cataract surgery and implantation of a new monofocal non-constant aberration aspheric intraocular lens (IOL).MethodsNinety eyes of 86 patients who underwent implantation the CT LUCIA 621P IOL (Carl Zeiss Meditec AG) were retrospectively analyzed in this study. Main outcome measures were refractive error and monocular corrected distance visual acuity (CDVA) and monocular uncorrected distance visual acuity (UDVA) values. Patients were evaluated at 1-month post-surgery and intra- and post-operative complications were recorded.ResultsEighty percent of the eyes showed a CDVA of 20/25 or better before surgery. The postoperative mean values of monocular distance Snellen decimal UDVA and CDVA were 0.64±0.22 and 0.89±0.13, respectively. All eyes showed the same or better difference between UDVA and CDVA. In relation to the postoperative spherical equivalent, the highest percentage of eyes, 31.11%, was for the range between −0.50 and −0.14D followed by 22.22% for the ±0.13D range. Ninety percent of the eyes were within ±1.00 D and 73.33% of eyes within ±0.50 D. The mean postoperative spherical equivalent was −0.18±0.55D. 37.78% and 76.67% of the eyes showed a value ≤0.50 D and ≤1.00D, respectively, being the mean postoperative refractive cylinder −0.81±0.50D. No adverse events were reported in whole sample intra and postoperatively.ConclusionThe present study shows that cataract surgery with an monofocal non-constant aberration aspheric IOL implantation resulted in good visual performance and refractive outcomes. This lens may be considered as a valid choice for patients in a standard-routine cataract surgery practice.

Commentary: Aspheric intraocular lens may be the future but not always a simple solution.

Nowadays, cataract surgery is not only to achieve the vision of 20/20; rather, it demands many other qualities of vision to be fulfilled as described by Despande et al.[1] Spherical aberration is one of the varieties of higher-order aberration (HOA) in the eye. The optical design of the aspheric intraocular lens (IOLs) reduced spherical aberrations and increased contrast sensitivity as described by Despande et al.[1] As described by the authors, the crystalline lenses lose their property of negative spherical aberration to compensate for the positive spherical aberration of the eye with overall near-zero spherical aberration of the young adult eyes or very minimal spherical aberration. Wavefront technology is used nowadays more frequently by an aberrometer to map the eye before any refractive surgery to detect any aberration so that customized compensatory optical solution can be done to that eye to achieve the best possible functional vision. Patients having age-related cataracts not only suffer from a decrease in vision but also loss of contrast, especially in mesopic conditions. They did not realize it at that time due to cataracts but after cataract surgery when their contrast also improves along with their vision they are the happiest patients. Theoretically, spherical aberrations increase the depth of focus but decrease modulation transfer function at high spatial frequencies at optimum focus. Spherical aberrations, therefore, play an important role in the balance between visual acuity and depth of focus.[2] Although aspheric IOLs are replacing the spherical IOLs in our country, still PMMA rigid IOL is implanted frequently in below poverty line ( BPL) and ration cardholder patients due to the issue of affordability. Another point to be noted is that the asphericity of aspheric IOL is lost and even leads to more aberrations such as coma and coma-like effects if the IOL is slightly decentred and tilted and these aberrations occur more in aspheric IOL than in spheric IOL and monofocal IOL than multifocal IOL in such scenarios.[3] That is the reason in 1980 and 1990 there was a reluctance for aspheric IOL. However, after the evolvement of phacoemulsification, better surgery techniques such as proper rhexis size, the problems of decentration and tilt has got reduced quite a lot so more and more aspheric IOLs are implanted. The spherical aberration reduced significantly in these aspheric IOL in larger pupil aperture such as in young patients who have undergone corneal refractive surgery, especially in mesopic and scotopic conditions. Thus, the aged population with a small pupil size and having less mesopic and scotopic activity may not need the aspheric IOL. Wavefront technology is used more before corneal refractive surgery or biopics, to measure the corneal and total aberration of eyes so that customized surgery can be planned accordingly for a better functional optical outcome. The future generation of cataract surgery will not be for the recognition acuity only rather for fully functional visual outcome and aberration-free vision. With the better technique of cataract surgery, day by day such as higher competency in phacoemulsification and nowadays femto laser-assisted cataract surgery where precise capsulorhexis is done, more and more aspheric IOL will be the choice of IOL in the coming days.

Effects on ocular aberration and contrast sensitivity after implantation of spherical and aspherical monofocal intraocular lens - A comparative study.

Phacoemulsification with intraocular lens (IOL) implantation is the standard of care for cataractous eyes. Monofocal IOLs are spherical or aspheric. The aspheric design of IOLs reduces the spherical and higher-order aberrations and impacts contrast sensitivity post cataract surgery. There are some studies, but data in the Indian setting with the IOLs we used is lacking. We aimed to compare the effect of implantation of spheric and aspheric foldable intraocular lenses on postoperative quality of vision, spherical aberration, and contrast sensitivity. This prospective observational study was conducted at a tertiary care hospital with an ophthalmology specialty, data collection from January 2017 to May 2018 in 100 patients. Patients meeting the inclusion criteria were selected. Their preoperative and postoperative data were collected and divided into groups based on whether spherical or aspheric IOL was implanted after cataract surgery. Variables assessed were visual acuity on days 7 and 30, spherical aberrations, and contrast sensitivity was assessed at 1-month postoperative. The mean age of the patients in this study was 64 ± 8 years with a majority of patients (60%) being females. There is no significant difference in postoperative visual acuity between the two groups. Internal SA was significantly lower (~50%) in eyes implanted with aspheric IOLs (P value = 0.004, 0.0001) compared with the spherical group. Contrast sensitivity of patients of the aspheric group was significantly better (P value <0.05). The optical design of the aspheric IOLs reduced spherical aberrations and increased contrast sensitivity.

Comparative study of decentration, tilt and visual quality after implantation of aspherical intraocular lenses

Objective: To compare the difference of decentration and tilt among 4 kinds of aspherical intraocular lenses (IOLs), and to analyze their objective visual quality. Methods: Prospective non-randomized controlled clinical trial. Age-related cataract patients who planned to undergo phacoemulsification and IOL implantation in the Affiliated Hospital of North Sichuan Medical College from April to June in 2020 were divided into ZCB00 group, SN60WF group, A1-UV group, and AO group according to IOL types. Thirty right eyes and thirty left eyes were selected in each group. Before operation and at 1 day, 1 week and 1 month postoperatively, decentration and tilt values were measured by a new swept-source anterior-segment optical coherence tomography device (CASIA2), and wavefront aberrations, objective scatter index (OSI), modulation transfer function cut off frequency (MTF cut off) and Strehl ratio (SR) were also examined. Values of decentration, tilt and visual quality compared among 4 groups were took from the right eye. One-way analysis of variance was used for inter-group comparison, and repeated measurement one-way analysis of variance was used for intra-group comparison. Data between right eyes and left eyes from all the individuals were compared by independent sample t-test. Results: A total of 181 patients (240 eyes) were enrolled, and 169 patients (224 eyes) completed the follow-up (114 right eyes and 110 left eyes). There were 77 males and 92 females, with an age of (69±9) years. There was no significant difference in gender, age, axial length, decentration and tilt of crystalline lens and IOL power among 4 groups (all P>0.05). At 1 day, 1 week and 1 month postoperatively, there was significant difference in decentration value among 4 groups (F=7.11, 6.12, 4.66; all P<0.05). For further pairwise comparison, the decentration value of SN60WF group was higher than that of the other 3 groups at 1 day and 1 week postoperatively, and the decentration value of SN60WF group was (0.259±0.101) mm at 1 month postoperatively, which was higher than that of ZCB00 group (0.177±0.099) mm and AO group (0.163±0.122) mm, and the differences were statistically significant (using SNK-q test, both P<0.05). The IOL tilt value in the ZCB00 group, SN60WF group, A1-UV group, and AO group at 1 month postoperatively were (4.806±1.129)°, (5.080±1.309)°, (4.586±1.338)°, (5.112±1.406)°, respectively. No significant difference in tilt value among 4 groups was found at any time after surgery (all P>0.05). In each group, there was no significant difference in decentration and tilt value at different postoperative time points (all P>0.05). At 1 month postoperatively, there was no significant difference in decentration and tilt at horizontal and vertical directions respectively among 4 groups (all P>0.05), and in each group, there was no significant difference in decentration and tilt value between right eyes and left eyes (all P>0.05), and IOLs tended to tilt towards the inferonasal or inferotemporal direction in both eyes. With 4-mm and 6-mm pupil diameter, there was significant difference in internal (F=131.32, 85.17) and ocular (F=46.64, 47.55) spherical aberration among 4 groups (all P<0.01). For further pairwise comparison, the spherical aberration of AO group was higher than that of the other 3 groups, and the difference was statistically significant (using SNK-q test, all P<0.05). There was no significant difference in OSI, MTF cut off and SR among 4 groups (all P>0.05). Conclusions: The four types of IOLs show decentration and tilt in varying degrees after implantation in the capsular bag, but this difference do not lead to clinical significance. Human eyes have tolerance to mild decentration and tilt of aspheric IOLs, showing good visual quality.

Enhanced Stereopsis of Rotationally Asymmetric Multifocal Intraocular Lens With + 1.5 Diopters Near Addition.

To the Editor: Stereopsis is the highest level of binocular vision and contributes to the determination of depth and distance in solid object recognition. Currently, multi-focal intraocular lenses (IOLs) with various added powers are selected based on patient preferences and lifestyles. The European Society of Cataract and Refractive Surgery (ESCRS) Functional Vision Working Group report1 emphasized the importance of the postoperative functionality of near and intermediate vision, which are necessary for everyday activities. Conventional multifocal IOLs with 2 distinct foci provide patients with good far and near vision, but unsatisfactory intermediate vision. The use of low-addition multifocal IOLs (low-add IOLs) can improve intermediate vision.2 Herein, we discussed the stereopsis from far to near in patients implanted with low-add IOLs. Twenty-one patients bilaterally implanted with the low-add IOL (Lentis Comfort LS-313MF15 IOL, Santen Pharmaceutical) (69.7 ± 5.2 years, Low-add group) and 22 with the aspheric monofocal IOL (Tecnis ZCB00 V, Johnson & Johnson Surgical Vision) (69.7 ± 5.2 years, Monofocal group) were examined. All surgeries were performed using a standard technique of sutureless phacoemulsification under topical anesthesia by the same experienced surgeon. The low-add IOL was a foldable plate-haptic, rotationally asymmetric, refractive multifocal IOL, combining an aspheric distance vision zone and a sector-shaped near vision zone with an add power of + 1.5 diopters (D) on the lens plane, that was positioned inferiorly. Inclusion criteria were: 1) having postoperative distance-corrected visual acuity (DCVA) of Snellen 20/25 or better in both eyes, 2) refraction difference of < 2.0 D between both eyes, and 3) without manifest strabismus. DCVA and stereoacuity were measured at far (5 m, 2 m), intermediate (1 m, 70 cm, 50 cm), and near (30 cm) using a Binoptometer 4 P (Oculus Optikgeräte GmbH) at 2 months postoperatively. Significantly better distance-corrected intermediate visual acuity, and distance-corrected near visual acuity were attained in the Low-add group than in the Monofocal group (P < 0.001 for 50 cm and 70 cm; P < 0.01 for 30 cm and 1 m) (Supplemental Digital Content Fig. 1A, http://links.lww.com/APJO/A122) Stereoacuity at 30 cm and 50 cm was significantly better in the Low-add group than in the Monofocal group (Supplemental Digital Content Fig. 1B, http://links.lww.com/APJO/A122). The rates of normal range3 (≤ 100 seconds of arc for 5 m, 2 m, 1 m, 70 cm, 50 cm, and 30 cm) were 85%, 77%, 81%, 58%, 53%, and 24% in the Low-add group, while they were 82%, 64%, 59%, 37%, 18%, and 0% in the Monofocal group. The rates of normal range at 30 cm (P = 0.002) and 50 cm (P = 0.017) in the Low-add group were significantly higher than those in the Monofocal group. Consistent with a previous study,4 a low-add IOL provided good postoperative far and intermediate visual acuity. Unlike the double-peak curve pattern observed with conventional far/near bifocal IOLs, the DCVA showed a gradual decrease from far to near. The Titmus stereoscopic test is the most common test measured at a standardized distance (40 cm) as near ster-eoacuity. The current study measured ster-eoacuity under binocular natural viewing conditions at several distances to assess stereopsis similar to those experienced in everyday life. In the Monofocal group, the DCVA and the rates of the normal range of stereoacuity decreased with a shorter target distance. At a distance of 30 cm, no patient showed a normal range of stereoacuity. The effects of optical blur on stereopsis5 have been reported and are comparable to the results in the Monofocal group. In contrast, a normal range of stereoacuity was attained for 1 m to 5 m in approximately 80% of patients in the Low-add group. The Cat-quest-9SF QoL questionnaire6 for assessing intermediate vision1 should have been utilized; however, its validated Japanese version is not currently available. In summary, the rotationally asymmetric multifocal IOLs with + 1.5 D near addition provided enhanced stereoacuity and vision at near and intermediate levels compared with monofocal IOLs. It may be an option for enhanced functional vision, leading to better overall patient satisfaction.

Evaluation of a Novel Non-Diffractive Extended Depth of Focus Intraocular Lens – First Results from a Prospective Study

Purpose To evaluate a novel hydrophobic, non-diffractive, extended depth of focus (EDOF) intraocular lens (IOL) design in comparison to two monofocal aspheric lenses. Methods Inclusion criteria for this prospective, monocentric cohort study were opacification of the crystalline lens and patients’ wishes for surgery. In the case of the EDOF IOL, patients asked for a presbyopia correction. All patients received surgery on both eyes. Corrected and uncorrected distance visual acuity (CDVA, UCDVA), uncorrected and distance corrected intermediate visual acuity (UIVA, DCIVA) and defocus curves (all monocular and binocular) were compared three months postoperatively. Results Fifty-six eyes were implanted with an EDOF IOL (LuxSmartTM, Bausch & Lomb GmbH, Berlin, Germany), 50 eyes with a monofocal aspheric IOL: 32 eyes with a clear IOL (Polylens® AS 61, Polytech Domilens, Roßdorf, Germany), 16 eyes with a yellow IOL (iSert® 251, Hoya Surgical Optics GmbH, Frankfurt, Germany). Three months postoperatively, UCDVA was comparable with the EDOF IOL, versus the monofocal IOL (P > 0.9). Binocular DCIVA in the EDOF IOL was significantly higher than in the monofocal IOL (P = 0.001). Monocular DCIVA better than 20/23 Snellen was achieved in 10% with the monofocal IOL and in 68% (P < 0.0001) with the EDOF IOL. Defocus curves showed a depth of focus at 20/23 Snellen of 1.6 vs. 0.83 diopters (D) in the EDOF IOL, vs. the monofocal IOL. No patient reported halos or starbursts in non-standardized questioning. Conclusion This non-diffractive EDOF IOL provided comparably high UCDVA and significantly higher DCIVA than the mono-focal lenses, causing only mild optical phenomena.

Effect of decentration on the quality of vision: comparison between aspheric balance curve design and posterior aspheric design intraocular lenses.

To study the effect of decentration on the quality of vision in 2 aspheric intraocular lenses (IOLs): aspheric balance curve (ABC) design Vivinex iSert XY1 (Hoya Surgical Opticals, Inc.) and posterior aspheric design AcrySof IQ SN60WF (Alcon Laboratories, Inc.). Advanced Eye Centre, PGIMER, Chandigarh, India. Randomized prospective trial using a random number table. 85 eyes were randomized to group 1 (Vivinex XY1) and group 2 (AcrySof IQ) with 40 and 45 eyes, respectively. The higher-order aberration (HOA) profile, Strehl ratio, decentration of the IOL from the visual axis (decentration from the visual axis [DVA]) and the geometric axis (decentration from the geometric axis [DGA]), angle α, and κ were recorded on the iTrace aberrometer, and contrast sensitivity was measured using the Functional Acuity Contrast Test at 12 weeks postsurgery. A total of 85 eyes in 60 patients were evaluated in this study. The mean values of the Strehl ratio (P = .48) and the HOAs (P = .12) of both IOLs were comparable. The HOAs gradually increased with increasing DVA for both lenses at 3.0 mm, 4.0 mm, and 5.0 mm pupil sizes. On comparing the HOAs with the DGA, a statistically insignificant positive correlation was observed. The Strehl ratio did not deteriorate with an increasing angle α in the Vivinex XY1 group; however, it worsened in the AcrySof IQ group. Contrast sensitivity was comparable in both the IOLs except at 1.5 cycles per degree under photopic conditions where the AcrySof IQ was better. Decentration of the lens was best measured with respect to the visual axis. In eyes with a large α, the ABC design induced lesser HOAs and maintained a better Strehl ratio.

Tilt and decentration with various intraocular lenses: A narrative review.

We find that tilt and decentration of intraocular lens (IOL) commonly cause visual quality deterioration after cataract surgery. Multiple factors affect IOL tilt and decentration in the pre-, mid-, and post-operation phases. Moreover, the tilt and decentration of 1-piece IOL are less correlated with internal ocular HOAs than those of 3-piece IOL. Aspherical IOLs are more sensitive to decentration or tilt than spherical IOLs. Furthermore, the optical performance of toric IOLs with an accurate axis remains stable irrespective of tilt and decentration. The optical quality of asymmetric multifocal IOLs varies significantly after decentration and tilt in different directions. The image quality enhances or deteriorates in the direction of the decentered IOL. An extended depth of focus IOL can achieve good visual acuity in the distant, intermediate, and near range. Additionally, its tilt and decentration have less impact on the vision than bifocal and trifocal IOL. This is the first review that compares the effect of IOL tilt and decentration on image quality for various IOL designs. The result indicates that a deeper understanding of tilt and decentration of various IOLs can help achieve a better visual effect to visually improve refractive cataract surgery.

Project Hyperopic Power Prediction II: The Effects of Second Eye Refinement Methods on Prediction Error in Hyperopic Eyes

Purpose The purpose of the study was to evaluate the potential accuracy of different second eye refinement methods in a patient cohort with short axial eye length to assess the performance of intraocular lens (IOL) power calculation schemes in high hyperopes. Methods The study design was a single-center, single-surgeon retrospective consecutive case series. The setting of the study was in Augen- und Laserklinik, Castrop-Rauxel, Germany. Patients were assessed after uneventful bilateral cataract surgery implanting either spherical (SA60AT) or aspheric (ZCB00) IOLs. Inclusion criteria were an axial eye length of ≤21.5 mm and/or emmetropizing IOL power of >28.5 dpt. Outcome measures were the mean absolute prediction error (MAE), median absolute prediction error, mean prediction error with standard deviation, median prediction error, and the percentage of eyes with an absolute prediction error (absPE) within 0.25 dpt, 0.5 dpt, 0.75 dpt, or 1.0 dpt. Second eye refinement was performed using the first eye prediction error, either with a correction coefficient of 0.50 (SER1), or an individual coefficient optimized for MAE. Results A total of 55 patients were assessed. A statistically significant reduction in the absPE after the application of SER1 was observed in 9 of 13 formulae. The SER1 refined Hoffer Q, refined Holladay I, refined Holladay II, refined Kane, refined Okulix, and refined PEARL-DGS provided a smaller absPE than other methods. Conclusion In this patient cohort with a short axial eye length, the second eye refinement led to a lower MAE in almost all formulae. The use of refinement in Kane, Okulix, PEARL-DGS, and Castrop formulae exhibited the lowest MAE.

Comparison of Visual Outcomes Between Toric Intraocular Lenses and Clear Corneal Incisions to Correct Astigmatism in Image-Guided Cataract Surgery.

PurposeTo compare the astigmatism correction effects of toric intraocular lenses (IOL) and clear corneal incisions during image-guided cataract surgery.MethodsAll patients with regular corneal astigmatism of 0.75–1.5 D underwent cataract surgery and astigmatism correction using the Callisto eye image-guided system. One group had implantation of an AcrySof toric IOL. Another group had implantation of aspheric IOL with 3.0 mm single clear corneal incision (SCCI) on the steep axis. Uncorrected and best-corrected spectacle visual acuity, refraction, and toric IOL axis were evaluated at 1, 4, and 12 weeks postoperatively.ResultsSixty-eight eyes of 68 patients were included. The mean residual refractive cylinder was 0.34 ± 0.40 D in the toric group and 0.64 ± 0.57 D in the SCCI group. There were no significant differences in residual refractive cylinder, spherical equivalent, uncorrected distance visual acuity (UDVA), and best-corrected spectacle visual acuity (BCSVA) between groups. The percentage of the residual cylinder within ± 0.50 D was 75 and 56% for toric and SCCI cases, respectively (p > 0.1). The mean surgical induced astigmatism vector was 0.61 ± 0.29 D in the SCCI group and 1.04 ± 0.38 D in the toric group. The mean magnitude of error was negative (−0.54 ± 0.48 D) and the correction index was <1.0 (p < 0.05) in SCCI group. At 3 months, all toric IOL alignment errors were within 5 degrees from the intended axis.ConclusionsBoth toric IOL and SCCI can correct low and medium astigmatism effectively with the help of a precise image-guided system.

Randomized contralateral comparison of visual outcomes following implantation of two monofocal aspherical intraocular lenses after cataract surgery.

To compare optical and visual performances of two one-piece aspherical implanted intraocular lenses (IOLs) following phacoemulsification cataract surgery in a contralateral eye study. In this prospective randomized parallel-group study, 25 patients with bilateral age-related cataract were implanted in one eye with the EnVista IOL (MX60, Bausch & Lomb Corporations, Rochester, NY, USA) and the Acrysof IQ IOL (Acrysof IQ SN60WF, Alcon Surgical Laboratories, Fort Worth, TX, USA) in the other eye. Uncorrected and corrected distance visual acuity (UDVA, CDVA), refractive status, higher-orders aberrations (HOAs) in 5 and 6mm pupil size, contrast sensitivity (CS) with and without glare, color vision status, and patient satisfaction were assessed in the two eyes at 1 and 3months after surgery. There was no significant difference in CDVA (P > 0.99), UDVA (P = 0.46), spherical equivalent refractive error (P = 0.63), CS with and without glare across different spatial frequencies, color vision, and root mean square (RMS) of aberrometric values between the two IOLs after 3-month follow-up. Spherical aberration with 5 and 6mm pupil sizes (P = 0.02) and horizontal coma with a 6mm pupil size (P < 0.001) were lower with the EnVista IOL. Patient's satisfaction showed no cases of dissatisfaction, and most patients were highly or moderately satisfied with both IOLs. The visual and optical performance of eyes implanted with the EnVista IOL or the Acrysof IQ IOL was similar, although the aberration profile differed.

Impact of Decentration and Tilt on Spherical, Aberration Correcting, and Specific Aspherical Intraocular Lenses: An Optical Bench Analysis

Introduction: The human eye is not optically symmetrical, and very few intraocular lens (IOLs) are perfectly centered in the eye. That is why contrast sensitivity can degrade in some conditions, especially in low light. In an optical bench analysis, we compare spherical (A), aberration correcting (B), and specific aspherical lenses (C) in terms of impact of decentration and tilt on the modulation transfer function as well as the simulated overall quality with USAF test targets. Material and Methods: The OptiSpheric IOL PRO2 was used to measure the optical performance of IOLs (A, B, C). In order to assess the optical quality of the IOLs, the optical quality parameters for the aperture size of 3.0 mm and 4.5 mm at the IOL plane were assessed. Through Frequency Modulation Transfer Function (MTF) and Strehl Ratio (SR) values, as well as the “US Airforce 1951 resolution test chart images” as qualitative simulation, were analyzed. All measurements (ISO) were repeated and done for centered, decentered (1 mm), and tilted (5°) IOLs. Results: Centered: The MTF (mean) at 50 lp/mm (IOL A, B, C) with 3.0-mm aperture was 0.794/0.716/0.797 (ISO-1 cornea) and 0.673/0.752/0.723 (ISO-2 cornea) and with 4.5-mm aperture 0.728/0.365/0.751 (ISO 1) and 0.276/0.767/0.505 (ISO 2). The SR (mean) with 3.0-mm aperture was 0.763/0.829/0.898 and with 4.5-mm aperture 0.228/0.386/0.432. Decentered by 1 mm: The MTF (mean) at 50 lp/mm with 3.0-mm aperture was 0.779/0.459/0.726 (ISO 1) and 0.695/0.381/0.662 (ISO 2). The MTF (mean) at 50 lp/mm with 4.5-mm aperture was 0.732/0.348/0.653 (ISO 1) and 0.355/0.069/0.346 (ISO 2). The SR (mean) with 3.0-mm aperture was 0.829/0.543/0.397 and with 4.5-mm aperture was 0.259/0.145/0.192. Tilted by 5°: The MTF (mean) at 50 lp/mm with 3.0-mm aperture was 0.731/0.705/0.751 (ISO 1) and 0.623/0.727/0.732 (ISO 2). The MTF (mean) at 50 lp/mm with 4.5-mm aperture was 0.579/0.406/0.701 (ISO 1) and 0.277/0.512/0.429 (ISO 2). The SR (mean) with 3.0-mm aperture was 0.539/0.478/0.514 and with 4.5-mm aperture was 0.262/0.136/0.201. Conclusion: Aberration correcting IOLs perform best when perfectly centered. The optical performance of aberration correcting IOLs can be markedly downgraded by misalignment. The examined ZO optic performed well in decentration and tilt. The ZO concept seems to be a good alternative to aspheric lenses, as it achieves to combine benefits of spherical and aspheric intraocular lenses. There is no perfect IOL, but fitting and choosing the right one for the individual case seems to be crucial to take advantage of benefits and minimize disadvantages. This is why knowledge of optical properties is also mandatory for the surgeon.

Clinical experience with an anti-dysphotopic intraocular lens.

PURPOSE:Report experience regarding an anterior capsulotomy fixated intraocular lens (IOL) designed to prevent negative dysphotopsia (ND).METHODS:A prospective, nonrandomized clinical study was done at Péterfy Sándor Street Hospital-Clinic, and Jenő Manninger National Trauma Institute, Budapest, Hungary. The Morcher (Masket) 90S IOL has a circumferential groove on the optic that captures the anterior capsulotomy. Thus, part of the optic projects over and anterior to the capsule edge, while the bulk of the IOL is fixated within the capsular bag. We implanted the first version of the 90S IOL into the 40 eyes of 38 patients. These 40 eyes made up the primary investigational cohort. An additional 22 eyes received a modified version of the 90S IOL. The main outcome measure was the presence of ND. There was also a control group of 40 patients who received a single-piece monofocal aspheric hydrophobic acrylic IOL (877 FAB, Medicontur, Budapest, Hungary).RESULTS:None of our 66 test patients experienced ND during the follow-up period. After specific questioning, six patients reported nondebilitating PD that improved or disappeared completely in 5 cases. For the 40 eyes of the control group, there were 10 cases of ND on the first postoperative day and in 2 cases ND persisted for more than 1 year postoperatively.CONCLUSION:The 90S IOL can be used successfully to prevent ND. Since it is fixated by the anterior capsulotomy, additional advantages such as prevention of anterior capsule contraction, limited tilt, stable toric axis, perfect centration on the visual axis, and a more predictable lens position, among others, may be expected, and are under investigation.

Optical bench simulation for intraocular lenses using field-tracing technology.

To evaluate the image quality of intraocular lenses (IOLs) using field-tracing optical simulation and then compare it with the image quality using conventional ray-tracing simulation. We simulated aspheric IOLs with a decenter, tilt, and no misalignment using an aspheric corneal eye model with a positive spherical aberration. The retinal image, Strehl ratio, and modulation transfer function (MTF) were compared between the ray-tracing and field-tracing optical simulation and confirmed by the results reported in an in vitro experiment using the same eye model. The retinal image showed interference fringes from target due to diffraction from the object in a field-tracing simulation. When compared with the experimental results, the field tracing represented the experimental results more precisely than ray tracing after passing over 400 μm of the decentration and 4 degrees of the tilt of the IOLs. The MTF values showed similar results for the case of no IOL misalignment in both the field tracing and ray tracing. In the case of the 200-μm decentration or 8-degree tilt of IOL, the field-traced MTF shows lower values than the ray-traced one. The field-tracing optical bench simulation is a reliable method to evaluate IOL performance according to the IOL misalignment. It can provide retinal image quality close to real by taking into account the wave nature of light, interference and diffraction to explain to patients having the IOL misalignment.

Comparison Between an Intraocular Lens With Extended Depth of Focus (Tecnis Symfony ZXR00) and a New Monofocal Intraocular Lens With Enhanced Intermediate Vision (Tecnis Eyhance ICB00).

Purpose:This study compared the extended depth of focus (EDOF) intraocular lens (IOL) (ZXR00; Tecnis Symfony, Johnson & Johnson Vision, Santa Ana, CA, US) to a novel, higher-order aspheric monofocal IOL (ICB00; Tecnis Eyhance, Johnson & Johnson Vision, Santa Ana, CA, US) which uses the same platform and material.Methods:Medical records of patients undergoing cataract surgery with ZXR00 or ICB00 implantation between March 2020 and January 2021 and with the data available for the 3-month visit were reviewed. The uncorrected near, intermediate, and distance visual acuity (VA); corrected distance VA; and optical quality parameters were the main outcome measures.Results:Among the 174 enrolled patients, 72 and 102 received the ZXR00 and ICB00, respectively. The average patient ages were 59.6 ± 10.6 (range: 49 to 70) and 65.2 ± 8.2 (range: 45 to 82) years in the ZXR00 and ICB00 groups, respectively, with significantly older patients in the ICB00 group. The other baseline parameters were not different for the 2 groups. Compared to the ICB00 group, the ZXR00 group showed markedly superior near VA (P < 0.05) at 3 months postoperatively. In terms of optical quality, ICB00 was, statistically, significantly superior to ZXR00.Conclusions:The ZXR00 showed remarkable near vision and defocus curve smoothness, while the ICB00 achieved better optical quality. The 2 IOLs had comparable distance and intermediate vision.

Анализ влияния наклона и децентрации ИОЛ на индуцированный астигматизм при исследовании методом трассировки лучей на модели глаза

Purpose. Determination of the influence of the intraocular lens (IOL) inclination and decentration on the magnitude of induced astigmatism in a theoretical study using software on an eye model. Material and methods. An eye model with the specified parameters was performed to carry out the calculation. Modulation of the change in the wavefront was carried out using the Zemax program (LLC, USA). In the model eye, the probability of induction of astigmatism was analyzed depending on the change in the position of the aspherical IOL Acrysof IQ 16.0, 22.0 and 24.0 diopters and the toric model Acrysof IQ Toric SN6AT3, SN6AT4 and SN6AT5. The angle of inclination of the IOL relative to the horizontal plane was examined from 0° to 10° with a step of 1°, decentration from 0.1 to 1.5 mm with a step of 0.1 mm. At each IOL position, aberration data of the 2nd order Z (2, 2) were recorded. The obtained results were used to calculate the critical tilt angle and decentration. Results. The magnitude of induced astigmatism increased with the rise of the degree of inclination and decentration, corresponding to an increase in the optical power of the IOL. Accordingly, critically significant were the values of 3.0° inclination for the aspherical IOL with an optical power of 22.0 and 22.0 diopters and 3.5° for 16.0 diopters, decentration – 0.7 mm and 1.0 mm. The inclination of the TIOL relative to the horizontal plane revealed the induction of the magnitude of inverse astigmatism, according to an increase in the inclination angle of 0.3 diopters at a slope of 3–4°. Conclusions. The tilt and decentration of the aspherical and TIOL patterns induce astigmatism depending on the increase in IOL power. The inclination of the TIOL in relation to the horizontal plane set at 90 ° promotes the induction of astigmatism. Key words: astigmatism, toric intraocular lenses, tilt and decentration of the intraocular lens, ray tracing