Effect of Intraocular Lens Tilt and Decentration on Visual Acuity, Dysphotopsia and Wavefront Aberrations

Modified "C" Haptic Intraocular Lens Orientation and Negative Dysphotopsia

Phacoemulsification is the standard of care in cataract surgery in the developed world, with patients having high expectations regarding visual results. Postoperative dissatisfaction due to negative dysphotopsia (ND) ranges from rare to very frequent; its etiology is unclear, and it affects postoperative satisfaction. Since one of the most frequently used strategies to avoid ND is related to intraocular lens (IOL) haptic orientation, we conducted a prospective interventional study that enrolled 197 patients who underwent standard phacoemulsification. All patients had a one-piece hydrophobic acrylic IOL implanted; in one group, the haptics were placed in any meridional axis except inferotemporal (IT) meridians, and in the other group, the IOL was implanted with the haptics in an IT position. Our results showed no statistically significant differences between groups when analyzing the correlation between the position of IOL haptics and the presence of ND in week one and month one. Also, pupillary diameter showed no statistically significant differences between patients with or without ND. Despite some studies claiming that haptic orientation prevents ND, we found that haptic orientation does not correlate with ND incidence and that ND decreases from day 1 to month 1. Our results support previous findings on the decrease in ND over time and that haptic orientation should not be considered an intraoperative strategy to avoid this unwanted phenomenon.

Biometric factors associated with the postoperative visual performance of a multifocal intraocular lens

Purpose

To identify the biometric factors associated with postoperative visual performance after uneventful phacoemulsification with multifocal intraocular lens (MIOL) implantation.

Methods

In this retrospective cohort study, 72 eyes of 72 patients implanted with the HumanOptics Diff-aAY MIOL were included. Preoperative examination data including the white-to-white distance (WTW), anterior chamber depth (ACD), axial length and corneal astigmatism were gathered through the electronic medical records. One month postoperatively, the pupil parameters, corneal aberrations, corneal astigmatism, IOL tilts and IOL decentrations were measured using an OPD-Scan III aberrometer. Postoperative visual performance parameters were recorded as the visual acuity, depth of focus, modulation transfer function (MTF) and point spread function (PSF) values, area under log contrast sensitivity function (AULCSF), retinal straylight and visual function questionnaire scores. Univariate and multivariate linear regression analyses were then performed to evaluate the associations between the potential biometric factors and postoperative visual outcomes.

Results

Younger age predicted greater MTF and PSF values, better AULCSF and better retinal straylight (P < 0.05). A lower corneal trefoil predicted better MTF and PSF values (P < 0.05). Smaller IOL decentration predicted better distance-corrected near visual acuity, greater AULCSF and better retinal straylight (P < 0.05). A less negative spherical equivalent (SE) predicted better MTF values (P = 0.017), while a more negative SE predicted better Visual Function Index-14 (VF-14) questionnaire scores and satisfaction scores (P < 0.05). A higher IOL power predicted better best corrected distance visual acuity (P = 0.005). Lower preoperative corneal astigmatism predicted greater MTF values (P = 0.020). Lower postoperative corneal astigmatism, smaller corneal high-order aberrations (HOAs), smaller photopic pupil size, larger WTW and deeper ACD predicted a better AULCSF (P < 0.05).

Conclusions

IOL decentration, IOL power, age, preoperative and postoperative corneal astigmatism, SE, photopic pupil size, corneal trefoil, WTW, ACD and corneal HOAs were significantly associated with postoperative visual performance. These findings might aid in patient selection prior to MIOL implantation.

Comparison of toric intraocular lens tilt and decentration measurement using dynamic Purkinje-meter and anterior segment optical coherence tomography

AIMS

To present a new method of dynamic Purkinje-metry and to verify it by comparison with a commercially available anterior segment optical coherence tomography CASIA2.

PATIENTS AND METHODS

A dynamic Purkinje-meter with a movable fixation target was assembled. A coaxial circular pattern formed by infrared LEDs was projected onto the eye and evoked Purkinje images (1st, 3rd, 4th = P1, P3, P4). The measurement was performed on 29 eyes with an implanted toric IOL (intraocular lens), under mydriatic conditions, with reference to the visual axis. The IOL tilt was calculated from the position of a fixation target at the moment of P3 and P4 superposition. The IOL decentration was determined based on the relative position of P1 during on-axis fixation and of P3 and P4 superposition during off-axis fixation. A custom-developed software was used for distance measurements. Using CASIA2, the IOL position was fully calculated by the device.

RESULTS

The mean absolute difference between CASIA2 and Purkinje-meter values was 0.6° ± 0.4° for the tilt magnitude and 10° ± 10° for the tilt direction, and 0.11 mm ± 0.08 mm for the decentration magnitude and 16° ± 14° for the decentration direction. There was no statistically significant difference between the values determined by the two methods for the tilt and decentration direction. The differences were statistically significant for the tilt and decentration magnitude.

CONCLUSION

The values of IOL tilt and decentration direction are similar for both devices. The values of IOL tilt and decentration magnitude measured by Purkinje-meter are higher than those from CASIA2, but overall, they correspond to the values presented in other published studies.

Analysis of intraocular lens decentration and tilt after femtosecond laser-assisted cataract surgery using swept-source anterior optical coherence tomography

Objective

To evaluate and compare the magnitude of intraocular lens (IOL) decentration and tilt following conventional and femtosecond laser-assisted cataract surgery (FLACS) using swept-source anterior optical coherence tomography (SS-OCT).

Methods

In this retrospective observational study, we enrolled patients who underwent conventional cataract surgery or FLACS with the implantation of hydrophobic 1-piece monofocal IOL. The magnitude of IOL decentration and tilt were measured using SS-OCT. Visual acuity, intraocular pressure, spherical equivalent, axial length, contrast sensitivity, and satisfaction questionnaire were evaluated before and one-month post-surgery. Additionally, postoperative internal cylinder measurements were obtained using a wavefront aberrometer. Correlation factors between each parameter and IOL decentration or tilt were analyzed.

Results

This study included 100 eyes from 100 patients. Mean IOL decentration and tilt were 0.21 ± 0.13 mm and 5.01 ± 1.49°, respectively. Conventional cataract surgery (versus FLACS, P = 0.001) and male sex (versus female, P = 0.047) were significantly correlated with higher postoperative decentration. Preoperative lens diameter (P < 0.001), preoperative lens tilt (P = 0.007), and preoperative intraocular pressure (P = 0.027) were correlated with higher postoperative tilt. Fifty eyes that underwent FLACS demonstrated mean postoperative decentration of 0.21 ± 0.13 mm and tilt of 4.64 ± 1.48°. Compared with the conventional surgery group, the FLACS group significantly differed in postoperative decentration (0.30 ± 0.12 mm, P < 0.001) but not in tilt (5.03 ± 1.35°, P = 0.173). Postoperative visual acuity did not significantly differ between the two groups.

Conclusion

Patients who underwent FLACS demonstrated better IOL decentration and tilt than those who underwent conventional cataract surgery one-month post-surgery. However, differences in IOL decentration and tilt did not affect postoperative visual acuity.

Pupil versus 1st Purkinje capsulotomy centration with femtosecond laser: Long term outcomes with a sinusoidal trifocal lens

PURPOSE

To assess the role of femtosecond laser-assisted capsulotomy centration in the long-term intraocular positioning of a multifocal intraocular lens.

DESIGN

Prospective comparative study.

METHODS

A total of 60 eyes of 30 patients underwent femtosecond laser-assisted Refractive Lens Exchange (RLE). For every patient, capsulotomy centration was randomly performed according to pupil centre (PC) in one eye and first Purkinje reflex (FPR) in the other. The intraocular lens (IOL) positioning, visual acuities, spherical equivalent, internal aberrometry and quality of vision were assessed and compared at 3 years' follow-up between groups (PC and FPR).

RESULTS

Intraocular lens positioning showed a statistically significant difference between groups, with a closer centration to the visual axis in the FPR patients (p < 0.001). Internal aberrometry showed higher values in the PC capsulotomy centration group (p < 0.01).

CONCLUSIONS

FPR centered capsulotomy is associated to a closer centration of the IOL to the visual axis.

An analysis of the factors involved in IOL decentration after phacoemulsification using CASIA 2 anterior segment optical coherence tomography

PURPOSE

To evaluate the magnitude of IOL transversal shift (ITS) after phacoemulsification and to analyse the factors contributing to IOL decentration and ITS.

METHODS

94 consecutive patients who underwent cataract surgery and IOL implantation was enrolled. Each patient underwent anterior segment optical coherence tomography with CASIA 2 (Tomey, Nagoya, Japan) to assess crystalline lens decentration, thickness and diameter seven days preoperatively and at one and sixty days postoperatively. Univariate and multivariate linear regression analysis were performed to evaluate the determinants of ITS and final decentration.

RESULTS

The preoperative crystalline lens diameter was associated with the ITS and with the IOL final decentration. A positive association between the final IOL decentration and the first post-surgical day decentration was found (p < 0.0001).

CONCLUSION

Greater crystalline lens diameter was associated with greater decentration and with greater ITS. Day-one IOL decentration seems to be the main determinant of final IOL decentration.

Effect of decentration and tilt on the in vitro optical quality of monofocal and trifocal intraocular lenses

PURPOSE

To evaluate and compare the effect of decentration and tilt on the optical quality of monofocal and trifocal intraocular lenses (IOL).

METHODS

Optical quality of a monofocal IOL (AcrySof IQ SN60WF; Alcon Laboratories, Inc., USA) and a trifocal IOL (AcrySof IQ PanOptix; Alcon Laboratories, Inc., USA) was assessed using an in vitro optical bench (OptiSpheric IOL R&D; Trioptics GmbH, Germany). At apertures of 3.0 mm and 4.5 mm, modulation transfer function (MTF) at spatial frequency of 50 lp/mm, MTF curve and the United States Air Force (USAF) resolution test chart of the two IOLs were measured and compared at their focus with different degrees of decentration and tilt. Optical quality at infinity, 60 cm and 40 cm and the through-focus MTF curves were compared when the two IOLs were centered at apertures of 3.0 mm and 4.5 mm. Spectral transmittance of the two IOLs was measured by the UV-visible spectrophotometer (UV 3300 PC; MAPADA, China).

RESULTS

The SN60WF and the PanOptix filtered blue light from 400 to 500 nm. Both IOLs at the far focus and the PanOptix at the intermediate focus showed a decrease in optical quality with increasing decentration and tilt. The PanOptix demonstrated enhanced optical quality compared to the previous gradient at the near focus at a decentration range of 0.3-0.7 mm with a 3.0 mm aperture, and 0.5 mm with a 4.5 mm aperture, whereas other conditions exhibited diminished optical quality with increasing decentration and tilt at the focus of both IOLs. When the two IOLs were centered, the SN60WF had better optical quality at infinity, while the PanOptix had better optical quality at 60 cm and 40 cm defocus. The optical quality of the SN60WF exceeded that of the PanOptix at far focus, with a 3 mm aperture decentration up to 0.7 mm and a 4.5 mm aperture decentration up to 0.3 mm; this observation held true for all tilts, irrespective of aperture size. As both decentration and tilt increased, the optical quality of the SN60WF deteriorated more rapidly than that of the PanOptix at the far focal point.

CONCLUSIONS

The SN60WF showed a decrease in optical quality with increasing decentration and tilt. Optical quality of the PanOptix at the near focus increased in some decentration conditions and decreased in some conditions, while it showed a decrease at the other focuses with increasing decentration. While tilt only had a negative effect on optical quality. When both IOLs were centered, the PanOptix provided a wider range of vision, while the SN60WF provided better far distance vision. At the far focus, the SN60WF has better resistance to tilt than the PanOptix, but the optical quality degrades more quickly when decentered and tilted.

Effect of decentration on the quality of vision in two aspheric posterior chamber intraocular lenses: A contralateral eye study

PURPOSE

To perform an intraindividual comparison of the quality of vision and the effect of decentration between two aspheric intraocular lenses: aspheric balanced curve (ABC) design Vivinex iSert XY1 (Hoya Surgical Optics, Singapore) and anterior aspheric design Tecnis ZCB00 (Abbott Medical Optics, CA).

SETTING

Tertiary Eye Care Centre.

DESIGN

Prospective, randomized comparative study using a random number table.

METHODS

Thirty patients were randomized to the implantation of Vivinex iSert XY1 in one eye and Tecnis ZCB00 in the contralateral eye. Then, 12 weeks postoperatively, a laser ray-tracing aberrometer was used to evaluate the visual Strehl ratio, higher-order aberrations (HOA), decentration of IOL from the visual axis and geometric axis, angle alpha, and angle kappa. Contrast sensitivity was measured using the functional visual analyzer.

RESULTS

The visual internal Strehl ratio was higher ( P < 0.05) at all pupil sizes and the spherical aberrations values were lower ( P < 0.05) at larger pupil sizes (5 mm and 6 mm) in the Vivinex group. The mean decentration from the visual axis in the Vivinex group was significantly more than that in the Tecnis group ( P < 0.01). With an increase in angle alpha, there was a greater decline in the visual Strehl ratio for Tecnis; however, there was a statistically significant decline at 3 mm pupil size for Tecnis ZCB00 ( P = 0.028). The contrast sensitivity was similar for both IOLs.

CONCLUSION

In comparison to an anterior aspheric design IOL, the ABC design IOL yielded better quality of vision, neutralized spherical aberrations to a larger extent, and provided a relatively superior quality of vision with decentration.

Screening for multifocal intraocular lens implantation in cataract patients in a public hospital

PURPOSE

To identify the rate and characteristics of cataract surgery candidates suitable for multifocal intraocular lens implantation among patients undergoing preoperative evaluation in a public hospital.

MATERIALS AND METHODS

Screening was performed based on the patient's medical records, comprehensive ophthalmic examination, optical biometry (Zeiss, IOL Master 700) and optical coherence tomography (OCT) (Heidelberg, OCT Spectralis) in accordance with the relevant indications and contraindications mentioned in the pertinent literature. Patients were included in the present study if they were eligible for bilateral cataract surgery. The exclusion criteria were the presence of central nervous system or motility issues, prior refractive surgery, the presence of astigmatism greater than 1 dioptre and/or the presence of important ocular comorbidities in either eye.

RESULTS

The study evaluated 1200 consecutive patients. Four hundred thirty-two patients (36%) were not eligible for bilateral surgery and were excluded from the study. Of the 768 patients included in the present study, 346 (45.1%) were considered suitable candidates. Four hundred twenty-two patients (54.9%) were excluded for one or both eyes. Among them, 121 (28.7%) were excluded because of retinal disease, 120 (28.4%) because of regular astigmatism (> 1.0 D of corneal astigmatism), 32 (7.5%) because of pseudoexfoliation or zonular instability, and 30 (7.1%) because of glaucoma or ocular hypertension; in addition, 90 (21.3%) patients were excluded for multiple reasons. Suitable candidates were significantly younger (70 and 75 years, respectively) (p < 0.001). After being informed about the potential risks and benefits of MOIL implantation, 212 of 346 (83.8%) eligible patients provided consent.

CONCLUSION

Close to half of cataract patients in a public hospital were eligible for MOIL implantation, and the majority of patients would proceed to surgery. The most prevalent contraindication was macular disease.

Bilaterally subluxed diffractive intraocular lenses: big expectations and even bigger comorbidities

A 78-year-old woman with an ocular history of cataract surgery with a diffractive intraocular lens (IOL) in each eye has developed fluctuating vision, greater in the right eye than the left eye, after 4 years. She has a history of inactive central serous retinopathy and a vision potential of 20/25 + 2 in the right eye and 20/25 in the left eye. She has well-controlled diabetes, hypertension, and hypercholesterolemia. She has enjoyed her spectacle independence for some time and wishes to have her vision restored. On examination, her uncorrected distance visual acuity (UDVA) was 20/50 in the right eye and 20/25 in the left eye and her uncorrected near visual acuity (UNVA) was J3 in the right eye and J1 in the left eye. Intraocular pressures (IOPs) measured 22 mm Hg in the right eye and 18 mm Hg in the left eye. Pupils had limited reactivity with irregularity in the right eye but no obvious relative afferent pupillary defect. Motility and confrontation visual fields were unremarkable in both eyes. Retinal acuity meter was 20/20 in both eyes, and manifest refraction was plano -1.25 × 105 20/40, J3 in the right eye and +0.50 × 20/25, J1 in the left eye. Pertinent findings on slitlamp examination included temporal iris atrophy and transillumination defects greater in the right eye than the left eye, peripupillary pseudoexfoliative changes in both eyes, significant inferior subluxation of a diffractive 3-piece posterior chamber IOL in the capsular bag with lens-pitting peripherally and few central, moderate pseudophacodonesis, and an open posterior capsule in the right eye. In the left eye, she had mild inferior subluxation of a single-piece acrylic diffractive IOL in the capsular bag with moderate pseudophacodonesis and an open posterior capsule (Figure 1JOURNAL/jcrs/04.03/02158034-202403000-00019/figure1/v/2024-02-20T193212Z/r/image-tiff). All other anterior segment findings were unremarkable. On dilated posterior examination, she had a cup-to-disc ratio of 0.50 in the right eye and 0.65 in the left eye without edema hemorrhage or pallor. There were attenuated vessels in both eyes, posterior vitreous detachment in both eyes, and a few small drusen peripherally in both eyes. There was retinal pigment epithelium irregularity and dropout parafoveal in the right eye and subfoveal in the left eye (Figure 2). There was no evidence of macular edema, subretinal fluid, choroidal thickening, or neovascular membranes. The periphery was unremarkable in both eyes.JOURNAL/jcrs/04.03/02158034-202403000-00019/figure2/v/2024-02-20T193212Z/r/image-tiff What testing would you obtain preoperatively to help guide your decision-making? How would you counsel the patient regarding comorbid conditions and expectations?

Severe astigmatism secondary to large intraocular lens pantoscopic tilt because of a malpositioned haptic following cataract surgery

An 80-year-old woman presented with painless blurring of vision and monocular diplopia in her left eye following routine phacoemulsification and monofocal intraocular lens (IOL) implantation 5 weeks earlier. Her uncorrected visual acuity (VA) was 6/60 correctable with pinhole to 6/21. Her best-corrected VA was 6/15 with a subjective refraction of -0.50DS/-5.25DCx37. Her corneal astigmatism was -1.25DCx74. Ophthalmic examination disclosed a severely tilted single-piece posterior chamber IOL in the capsular bag. The inferior portion of the optic was tilted posteriorly because of a twisted and malpositioned haptic. The patient underwent remedial surgery to untwist and reposition the IOL haptic which led to immediate improvement of the IOL position. Her uncorrected VA improved to 6/12-2 correctable with pinhole to 12+1 with an autorefraction of +0.25DS/-2.00DCx74 on the first postoperative day. One month postoperatively, her best-corrected VA was 6/12 with a refraction of +0.50DS/-2.50DCx82. Her final vision was limited by myopic macular degeneration.

Chord mu and chord alpha as postoperative predictors in multifocal intraocular lens implantation

PURPOSE

With the aging population, the prevalence of presbyopia and the popularity of multifocal intraocular lenses is also growing worldwide. Unfortunately, in some cases, they are still associated with postoperative visual disturbances. Recent literature started to evaluate angle kappa- and angle alpha-derived metrics of chord mu and chord alpha as possible predictive values for visual outcomes after multifocal intraocular lens implantation but the published results are inconsistent between studies. Thus, this article aims to review the role of chord mu and chord alpha as postoperative predictors after multifocal intraocular lens implantation and lay the foundation for further research.

METHODS

Relevant articles were identified using the following keywords: "presbyopia," "multifocal intraocular lens," "angle kappa," "angle alpha," "Chord mu," and "Chord alpha" up to June 2022. An attempt was made to present the majority of publications that addressed the topic.

CONCLUSIONS

Chord mu and chord alpha have a predictive role on the outcomes after multifocal intraocular lens implantation but to a different extent. Cataract surgeons should take them into consideration and avoid implanting a multifocal intraocular lens for patients with speculated critical values of chord mu and alpha above 0.5-0.6 mm, depending on the device used for measurement and the multifocal intraocular lens implanted. Currently, chord alpha seems to be a more stable, more widely applicable, and reliable determinant in predicting postoperative outcomes and in patient selection prior to multifocal intraocular lens implantation when compared to chord mu. To draw conclusions on the topic, a controlled study is needed.

Incidence and predisposing factors of intraocular Lens tilt following secondary ciliary sulcus implantation in children: An ultrasound biomicroscopic study

PURPOSE

To evaluate the incidence and causes of intraocular lens (IOL) tilt and changes in anterior chamber angle after secondary IOL sulcus implantation following congenital cataract removal.

METHODS

A retrospective observational study was conducted on children who underwent secondary sulcus IOL implantation following pediatric cataract removal in the period from 2017-2020 in Cairo university Hospitals. Children were examined for IOL position, centration, and tilt. Intraocular pressure (IOP) measurement, fundus and gonioscopic examination was performed. Ultrasound biomicroscopy (UBM) was performed on both eyes in children with clinically detected tilt.

RESULTS

Ciliary sulcus secondary IOL implantation was performed in 102 eyes (57 children). IOL tilt was detected clinically in 16 eyes of 14 children (15.7%). UBM showed clinically undetected tilt in the fellow eye in additional 4 eyes. The mean angle of tilt was 12.8 ± 3.9° in clinically detected tilt compared to 7.5 ± 1.2° in UBM detected tilt. Mean anterior chamber depth (ACD) was 2.4 ± 0.5 mm IOP was >21 mmHg in 1.9% of eyes. Narrowing of the anterior chamber angle (ACA) after sulcus implantation occurred in 40% of eyes with open angle. Sulcus proliferations and obliterated sulcus were detected in all 20 eyes. Sommering's ring was found in 7 eyes (35%). Axial length, corneal diameter, and presence of persistent fetal vasculature did not affect IOL position.

CONCLUSION

The presence of residual lens matter or an obliterated ciliary sulcus is associated with a higher incidence of IOL malposition following ciliary sulcus implantation.

Comparison of intraocular lens tilt after capsular sutured scleral fixation with capsular segments versus uneventful cataract surgery

PURPOSE

To evaluate and compare intraocular lens (IOL) tilt between uneventful phacoemulsification with in-the-bag IOL implantation and sutured scleral fixation (SSF) of the lens bag with a capsular tension segment (type 6 D / Morcher) using a Sheimpflug camera.

SETTING

Clinical Practice, Hospital. Barcelona and A Coruña, Spain.

DESIGN

Retrospective, comparative multicenter study.

METHODS

IOL tilt was compared between patients who underwent sutured scleral fixation with a capsular tension segment in a single eye (SSF group, n = 15) with patients who underwent uneventful IOL implantation (control group, n = 12) that were matched by biometric measurements. Post-operative refractive accuracy of biometric formulas by means of mean absolute error (MAE) was also reported. All patients underwent a general ophthalmic evaluation, anterior segment photography, and postoperative optical biometry (Zeiss IOLMaster® 500). In addition, IOL tilt was measured with a Scheimpflug camera (Pentacam R, Oculus Optikgerate Gmbh).

RESULTS

Mean vertical tilt was similar in both groups (2.20+/-2.47° SSF vs 1.97 +/- 1.79° control; p = 0.836) but mean horizontal tilt tended to higher values in the SSF series (2.09 +/- 2.74° vs 0.94 +/- 1.17°; p = 0.139). Considering post-operative refractive error in diopters by MAE calculations, there was an underestimation of IOL power in the SSF group which was only statistically significant for Barrett Universal II (1.07 vs 0.32; p = 0.028) and Hill-RBF (0.95 vs 0.26; p = 0.024) formulas, but not for SRK/T (0.99 vs 0.42; p = 0.285) and Kane (0.96 vs 0.33; p = 0.083).

CONCLUSION

Sutured scleral fixation of capsular tension segments in the presence of zonular instability does not seem to induce clinically significant IOL tilt compared to uneventful cataract extraction cases.

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.

Four-Point Flange Intrascleral Fixation With Double Suture Through the Dislocated Plate-Haptic Trifocal Intraocular Lens

PURPOSE

To describe a technique for the replacement of dislocation of plate-haptic trifocal intraocular lens (IOL) through double-suture 4-point flange intrascleral fixation.

DESIGN

Retrospective, interventional, noncomparative, case series.

METHODS

A total of 7 eyes of 7 patients with a dislocated plate-haptic trifocal IOL were enrolled for 4-point flange intrascleral fixation with double 7-0 polypropylene suture. Preoperative and postoperative visual acuity, operating time, refractive results, postoperative IOL tilt and decentration, and intraoperative and postoperative complications were recorded.

RESULTS

The mean postoperative uncorrected distance visual acuity (UDVA) was 0.05 ± 0.06 logarithm of the minimum angle of resolution (logMAR). The mean postoperative uncorrected intermediate visual acuity (UIVA) at 80 cm was 0.09 ± 0.06 logMAR and the mean postoperative uncorrected near visual acuity (UNVA) at 40 cm was 0.06 ± 0.07 logMAR. The mean postoperative residual spherical equivalent values were -0.27 ± 0.39 diopters. The visual function index-14 questionnaire showed that no difficulty was found in >80% of subjects for all tasks. The mean surgical time was 16.23 ± 5.64 min. The mean tilt of IOL was 3.74° ± 1.31° and the mean decentration of the IOL was 0.18 ± 0.09 mm. No important complications appeared.

CONCLUSION

We have described the technique of 4-point flange intrascleral fixation for plate-haptic trifocal IOL.

Bibliometric analysis of research relating to refractive cataract surgery over a 20-year period: from 2003 to 2022

AIM

To investigate the research trend on refractive cataract surgery, compare the contributions of different countries, institutions, journals, and authors in the past 20y, and explore its potential research hotspots.

METHODS

All publications were extracted relating to refractive cataract surgery from 2003 to 2022 from Web of Science. Document types were limited to original articles and reviews, and the language was limited to English. Quantitatively and qualitatively of the publications were analyzed through Microsoft Excel and GraphPad Prism. VOSviewer and CiteSpace were used for bibliometric and visualized analysis.

RESULTS

A total of 2090 publications were enrolled. The United States contributed the most publications (434, 20.8%), followed by China (345, 16.5%) and England (163, 7.80%). Publications from the United States were cited more frequently (9552 citations) with the highest H-index of 48. China ranked second in the total number of publications, the papers were not cited that frequently (3237 citations), and the H-index ranked sixth (H-index=29). Journal of Cataract and Refractive Surgery published the most papers (333, 15.9%), and the University of London had the highest number of publications (75, 3.59%). Dick HB from Germany published the most papers. Corneal astigmatism-related research, cataract surgery method-related research, postoperative visual-quality relate to research, and postoperative complications-relate research are the hotspots in this field. The most significant limitation was that the database was updated frequently and the latest publications were not included.

CONCLUSION

The bibliometric analysis shows a brief summarization of the contribution of the authors, institutions, countries, and journals. Corneal astigmatism, cataract surgery method, postoperative visual-quality and postoperative complications related researches have become the emerging hotspots, which can give a direction in the future researches.

Clinical and Anatomic Outcomes of 3-Piece Poly(methyl methacrylate) Intraocular Lens Rescue and Needle-Assisted Transconjunctival Intrascleral Lens Fixation

Purpose: To report the clinical and anatomic outcomes of a single-stage rescue and sutureless 30-gauge needle-assisted transconjunctival intrascleral fixation of dislocated 3-piece rigid poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs). Methods: This retrospective noncomparative single-surgeon interventional study comprised eyes that had concurrent 23- or 25-gauge pars plana vitrectomy and IOL rescue with sutureless transconjunctival needle-assisted flanged haptic intrascleral fixation. Lamellar scleral dissection for haptic fixation was performed 3 mm posterior to the surgical limbus with 30-gauge needles. Primary endpoints included visual acuity (VA), IOL tilt measured with ultrasound biomicroscopy (UBM), and postoperative complications. Results: The study evaluated 25 eyes of 24 patients. The IOL was successfully refixated in 24 of the 25 eyes. The mean preoperative logMAR VA of 1.21 ± 0.79 SD (median 1.3; Snellen equivalent 20/400) improved to 0.28 ± 0.35 (median 0.14; Snellen equivalent 20/30) postoperatively (P < .0001). The mean IOL tilt measured by UBM (n = 7) was 3.79 ± 3.60 degrees. The mean postoperative follow-up was 348 ± 284 days (range, 7-979 days). Postoperative complications included self-clearing vitreous hemorrhage (n = 9), retinal detachment (RD) (n = 1), cystoid macular edema (n = 3), and corneal edema (n = 3). Three eyes (13%) required additional surgery, 1 for RD and 2 for delayed haptic slippage and secondary IOL tilt causing irregular astigmatism. Conclusions: Intrascleral needle-assisted fixation of dislocated or mobile 3-piece PMMA IOLs is an effective, safe method to restore VA.

Comprehensive assessment of the anterior segment in refraction corrected OCT based on multitask learning

Anterior segment diseases are among the leading causes of irreversible blindness. However, a method capable of recognizing all important anterior segment structures for clinical diagnosis is lacking. By sharing the knowledge learned from each task, we proposed a fully automated multitask deep learning method that allows for simultaneous segmentation and quantification of all major anterior segment structures, including the iris, lens, cornea, as well as implantable collamer lens (ICL) and intraocular lens (IOL), and meanwhile for landmark detection of scleral spur and iris root in anterior segment OCT (AS-OCT) images. In addition, we proposed a refraction correction method to correct for the true geometry of the anterior segment distorted by light refraction during OCT imaging. 1251 AS-OCT images from 180 patients were collected and were used to train and test the model. Experiments demonstrated that our proposed network was superior to state-of-the-art segmentation and landmark detection methods, and close agreement was achieved between manually and automatically computed clinical parameters associated with anterior chamber, pupil, iris, ICL, and IOL. Finally, as an example, we demonstrated how our proposed method can be applied to facilitate the clinical evaluation of cataract surgery.

Influence of decentration of plate-haptic toric intraocular lens on postoperative visual quality

BACKGROUND

To evaluate the influence of decentration of plate-haptic toric intraocular lens (IOLs) on visual quality.

METHODS

This study enrolled 78 eyes of 78 patients. Patients in group A were implanted with toric IOLs, and patients in group B were implanted with monofocal IOLs. All patients were divided into group A1 and B1 (decentration below 0.3 mm) and group A2 and B2 (decentration above 0.3 mm). The uncorrected distance visual acuity (UDVA), best corrected visual acuity (BCVA), modulation transfer function cutoff (MTF cutoff), objective scatter index (OSI), strehl ratio (SR), optical interference and patients' satisfaction were measured in different pupils at three months postoperatively. The associations between decentration and visual quality were analyzed by Spearman correlation.

RESULTS

There were no significant differences in UDVA, BCVA, MTF cutoff, OSI, SR, optical interference and patients' satisfaction among subgroups. The differences in decentration between groups A and B were not statistically significant. In group A2, the total higher order aberrations (tHOAs) at pupil sizes of 3 mm (P = 0.046), 5 mm (P = 0.014), spherical aberrations at pupil sizes of 3 mm (P = 0.011), 4 mm (P = 0.014), 5 mm (P = 0.000), secondary astigmatism at pupil sizes of 3 mm (P = 0.002), 4 mm (P = 0.005) were higher than in group B2. Compared to group A1, group A2 had higher spherical aberrations at pupil sizes of 4 mm (P = 0.042), 5 mm (P = 0.001), 6 mm (P = 0.038), secondary astigmatism at pupil sizes of 3 mm (P = 0.013), 4 mm (P = 0.005), 6 mm (P = 0.013). Group B2 has higher coma and secondary astigmatism than group B1 at 6-mm pupil (P = 0.014, P = 0.045). Significant positive correlations were found between spherical aberrations and the decentration of group A1 and A2 at 6-mm pupils.

CONCLUSION

The decentration above 0.3 mm negatively affected visual quality due to increased tHOAs, spherical aberrations, coma and secondary astigmatism aberrations, the influence become larger with increasing pupil diameter. And toric IOLs are more affected by decentration than monofocal IOLs.

Intraocular lens tilt due to optic-haptic junction distortion following intrascleral haptic fixation with the Yamane technique

Purpose

To report two patients with a complication of Yamane intrascleral haptic fixation surgery (ISHF) with the Zeiss CT Lucia 602 lens: severely tilted intraocular lens (IOL) leading to significantly decreased vision in the early post-operative period.

Observations

We report two patients presenting with severely tilted IOL implants one day and one month following Yamane ISHF. The first patient is a monocular 81-year-old woman referred for treatment of cornea edema. Initial surgery involved replacement of an anterior chamber lens with a CT Lucia 602 posterior chamber lens using Yamane technique and Descemet's stripping endothelial keratoplasty. The patient returned at one month follow-up with poor vision and IOL tilt observable at the slit lamp through a peripheral iridectomy site. Explanation of the Zeiss lens revealed haptic distortion at the optic-haptic insertion point such that each haptic was about 45° off axis to the plane of the optic in approximately equal and opposite directions. The second patient, a 75-year-old woman, was referred with a completely dislocated lens-bag complex in the right eye. The initial operative treatment for this patient included pars plana vitrectomy, retrieval and removal of the dislocated lens-bag complex, and placement of a Zeiss 602 lens via Yamane ISHF technique. On the first postoperative day, the patient was count fingers in the right eye with an intraocular pressure of 5 mm Hg and obvious IOL tilt on slit lamp examination. Explanation of the lens revealed severely distorted haptics relative to the optic by more than a 60-degree angle on both sides. In both cases, initial surgery was performed with an IOL inspected prior to implantation and found to have normal appearing haptics. At the end of each case, there was adequate centration and no tilt of the IOL. Management in both patients included removal of the defective lens and placement of a new, same power CT Lucia 602 lens via the Yamane technique. Visual acuity improved from CF to 20/30 best corrected after reoperation in both cases.

Conclusions and importance

In summary, we describe a complication of Yamane ISHF with the CT Lucia 602 lens in which there is lens tilting associated with distortion at the optic-haptic fastening zone in the early postoperative period. In the event of a titled lens following Yamane ISHF, awareness of this complication may help surgeons consider lens replacement, as the haptics may be permanently distorted or damaged.

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

BACKGROUND/OBJECTIVES

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.

SUBJECTS/METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Optical performance of a new design of a trifocal intraocular lens based on the Devil's diffractive lens

In this work, we propose a new diffractive trifocal intraocular lens design with focus extension, conceived to provide a high visual performance at intermediate distances. This design is based on a fractal structure known as the "Devil's staircase". To assess its optical performance, numerical simulations have been performed with a ray tracing program using the Liou-Brennan model eye under polychromatic illumination. The simulated through the focus visual acuity was the merit function employed to test its pupil-dependence and its behavior against decentering. A qualitative assessment of the multifocal intraocular lens (MIOL) was also performed experimentally with an adaptive optics visual simulator. The experimental results confirm our numerical predictions. We found that our MIOL design has a trifocal profile, which is very robust to decentration and has low degree of pupil dependence. It performs better at intermediate distances than at near distances and, for a pupil diameter of 3 mm, it works like an EDoF lens over almost the entire defocus range.

Astigmatism Tolerance and Visual Outcomes After Bilateral Implantation of a Hybrid Continuous Transitional Focus IOL

PURPOSE

To evaluate the astigmatism tolerance and the visual outcomes after implantation of a premium intraocular lens (IOL) with a continuous transitional focus (Precizon Presbyopic; Ophtec BV) in pseudophakic presbyopia correction.

METHODS

This prospective study enrolled 20 patients (40 eyes) after bilateral phacoemulsification and IOL implantation. Corrected and uncorrected visual acuities at 4 m and 80, 67, and 40 cm (CDVA, UDVA, DCI80VA, UI80VA, DCI67VA, UI67VA, DCNVA, and UNVA), astigmatic and spheric defocus curve, mean reading speed (MRS), critical print size (CPS), contrast sensitivity, optical aberrations (modulation transfer function [MTF] cut-off, Strehl ratio, and higher order aberration root mean square [HOA RMS]), objective halometry, and National Eye Institute Refractive Error Quality of Life Instrument 42 [NEI RQL-42] questionnaire were evaluated 3 months after surgery.

RESULTS

Astigmatic defocus curves revealed a tolerance up to -1.00 and +0.75 diopters (D) for with-the-rule astigmatism, and up to -1.00 and +1.00 D for against-the-rule astigmatism. Binocular spheric defocus curve showed that the mean visual acuity was greater than 0.15 logMAR from 1.00 to -1.00 D. MRS, CPS, MTF cut-off, Strehl ratio, and HOA RMS were 116.97 ± 21.94 words/min, 0.45 ± 0.06 logRDA, 20.03 ± 4.86 cycles/degree, 0.11 ± 0.07, and 0.28 ± 0.09, respectively. Contrast sensitivity was within the normal range for all tested light conditions. The NEI RQL-42 evidenced high subjective satisfaction for all subscales, especially for far vision, activity limitations, dependence on correction, suboptimal correction, appearance, and satisfaction with correction.

CONCLUSIONS

The Precizon Presbyopic IOL allows good astigmatism tolerance and both objective and subjective high quality of vision. [J Refract Surg. 2023;39(1):33-39.].

Comparison of Visual and Aberrometric Outcomes in Suture-Free Scleral Fixation: Three-Piece Lenses versus Carlevale Lenses

Purpose: To compare the refractive results between sutureless scleral fixation intraocular lens (IOLs) (Carlevale, Soleko) and suture-free scleral fixation three-piece IOLs (Sensar AR40, Johnson & Johnson) for secondary implantation in patients with IOL dislocation or aphakia. Methods: This is a monocentric retrospective study on 28 patients (28 eyes) with sutureless scleral fixation Carlevale IOL and 25 patients (25 eyes) with suture-free scleral fixation three-piece IOL. Best-corrected visual acuity (BCVA) evaluation, refractive measures and IOL tilt evaluation with anterior segment optical coherence tomography were conducted at one, three, six and twelve months after surgery. Point Spread Function (PSF) was measured using a total ocular aberrometer. Results: BCVA in both groups improved since the postoperative visit at 1 month and reached a stable value at 3 months At month 12, mean BCVA was 0.23 logMAR in group one and 0.32 logMAR in group two. Mean IOL tilt angle at 12 months was 2.76° ± 1.87 in group one and 2.51° ± 1.80 in group two. PSF at 12 months was 0.18 ± 0.09 in group one and 0.15 ± 0.05 in group two. There were no statistically significant differences (p > 0.05) for all comparisons. The post-operative complications were similar within the two groups. Conclusions: Our results show that secondary IOL implantation has similar visual and surgical outcomes when a sutureless Carlevale lens scleral fixation and a suture-free scleral fixation three-piece IOL are used.

Short-term clinic observation of misalignment and rotational stability after implantable collamer lens implantation

PURPOSE

We aimed to investigate misalignment (tilt and decentration) and rotational stability of the implantable collamer lens V4c 6 months after implantation and to explore the potential risk factors associated with postoperative misalignment and rotation.

METHODS

A total of 36 eyes of 36 patients with high myopia and myopic astigmatism who underwent implantable collamer lens V4c implantation were included in this study. Tilt, decentration, and rotation of the implantable collamer lens were assessed postoperatively at l week, 1 month, 3 months, and 6 months. Correlation analysis was used to identify the potential risk factors for implantable collamer lens tilt, decentration, and rotation at 6 months postoperatively. Higher-order aberration was measured to evaluate the effect of implantable collamer lens misalignment on visual quality at pupil diameters of 4.0 mm and 6.0 mm.

RESULTS

The tilt and decentration at the last follow-up were 2.43 ± 1.35° and 0.278 ± 0.160 mm, respectively. There was a significant positive correlation between tilt and decentration (r = 0.31, P = 0.046). No significant correlation was detected between implantable collamer lens decentration and internal higher-order aberrations (P > 0.05). The degree of implantable collamer lens rotation (3.11 ± 2.00°) was significantly associated with the vault (r =  - 0.422, P = 0.01), while it was positively associated with the preoperative anterior chamber depth (r = 0.36, P = 0.034). No significant correlation was found between postoperative astigmatism and rotation (r =  - 0.07, P = 0.351).

CONCLUSIONS

The implantable collamer lens V4c provides relatively stable misalignment and rotation after implantation. The ICL lens vault is a potential risk factor for postoperative implantable collamer lens rotation. The absolute value of decentration and tilt was relatively small, which showed no correlation with internal higher-order aberration in short-term observation.

Effects of Modified Haptics on Surgical Outcomes and Rotational Stability of Toric Intraocular Lens Implantation

PURPOSE

To assess the rotational stability of a new toric intraocular lens (IOL), TECNIS toric II (toric II), which is a modified version of the TECNIS toric IOL (toric I) with frosted haptics (Johnson & Johnson).

METHODS

A total of 101 eyes of 101 patients who had been treated with phacoemulsification and toric IOL implantation were included. Before and 1 day, 1 week, and 1 month after surgery, uncorrected (UDVA) and corrected (CDVA) distance visual acuity were measured. Preoperative corneal astigmatism and postoperative manifest refractive astigmatism at 1 day and 1 month were analyzed. At 1 day and 1 month postoperatively, the amount of IOL axis misalignment from the intended orientation, tilt, and decentration were measured using anterior segment optical coherence tomography.

RESULTS

Fifty-one eyes received the toric I IOL and 50 eyes received the toric II IOL. Toric I IOLs showed a significantly larger amount of axis misalignment than toric II IOLs at both 1 day (9.6 ± 7.6° vs 5.4 ± 4.8°, P = .003) and 1 month (9.1 ± 7.8° vs. 4.7 ± 4.2°, P = .003) postoperatively.The proportion of eyes with misalignment greater than 10° was significantly larger with toric I than toric II IOLs (P < .001). There were no significant differences between IOLs in the amount of residual astigmatism, UDVA, CDVA, and amount of tilt and decentration at 1 day and 1 month postoperatively.

CONCLUSIONS

The TECNIS toric II IOL with frosted haptics has significantly improved rotational stability compared to its previous model. [J Refract Surg. 2022;38(10):648-653.].

Effect of decentration and tilt on four novel extended range of vision intraocular lenses regarding far distance

PURPOSE

To analyze the effect of decentration and tilt on four novel non diffractive extended range of vision intraocular lenses (IOLs).

METHODS

Acrysof Vivity, LuxSmart Crystal, RayOne EMV and Tecnis Eyhance were compared on the optical bench (power of 22 D each). Modulation transfer functions were obtained and Strehl ratio was calculated in an ISO-2 model. Apertures of 3 mm and 4.5 mm were applied. For qualitative assessment, United States Airforce (USAF) chart images were evaluated. Additional to centered IOLs, tilt of 5 degrees and decentration of 1 mm were applied.

RESULTS

RayOne EMV was very robust against misalignment but had considerable deterioration of modulation transfer function (MTF) for large aperture with USAF images seriously blurred. Tilt and decentration decreased the performance of Eyhance significantly but had minor impact on the performance of Vivity and LuxSmart. For 4.5 mm aperture, MTF and Strehl ratio decreased markedly for all IOLs compared to 3 mm aperture size. The best MTF and Strehl ratio was obtained for Eyhance IOL well centered for both sizes of aperture.

CONCLUSION

Tilt and decentration had a major impact on the performance of Eyhance only, which performed best of all IOLs tested when well centered. With large aperture, performance of all IOLs significantly decreased. Manufacturer's different approaches for these novel IOLs to increase depth of focus by increasing spherical aberration lead to a different performance in respect to contrast function and sensitivity to misalignment. Our results apply to the distance vision. Near vision performance will be evaluated in a separate investigation.

Presbyopia-correcting performance and subjective outcomes of a trifocal intraocular lens in eyes with different axial lengths: A prospective cohort study

Purpose

To compare the presbyopia-correcting performance, visual quality, satisfaction and life quality after implantation of a diffractive trifocal intraocular lens (IOL) in eyes with different axial lengths (AL).

Methods

This prospective cohort study enrolled patients with implantation of a trifocal IOL. Manifest refraction, uncorrected and distance-corrected visual acuity at different distances, contrast sensitivity, aberrations and IOL decentration were measured 3 months after surgery. Spectacle independence, adverse photic phenomena, overall satisfaction and life quality were assessed with a questionnaire.

Results

This study included 61 eyes of 61 patients: 16 eyes in the short AL group, 28 eyes in the control group and 17 eyes in the long AL group. Postoperatively, the prediction error (PE) of spherical equivalent showed a difference (P = 0.002). The uncorrected near visual acuity in the long AL group was higher (P = 0.047). Although a higher IOL decentration was obtained in the long AL group (P = 0.034), no significant difference was found in contrast sensitivity and aberrations (all P &gt; 0.05). In the questionnaire, patients in the long AL group showed a relatively lower spectacle independence at near distance (P = 0.060) and had difficulties in near activities, mental health and role in daily life (P = 0.003, 0.021, and 0.033). However, no significant difference was observed in overall satisfaction (P = 0.124).

Conclusion

With detailed preoperative evaluation, the trifocal IOL provided satisfactory visual outcomes for patients with different AL. AL had a certain influence on predictability and IOL decentration. And for patients with long AL, the inadaptability to the near focal point might become an important problem.

Risk factors associated with intraocular lens decentration after cataract surgery

PURPOSE

To identify risk factors associated with intraocular lens (IOL) decentration after uneventful phacoemulsification with IOL implantation.

DESIGN

A prospective cohort study METHODS: All patients underwent a general ophthalmologic examination. One month postoperatively, the magnitude and orientation of IOL decentration relative to the visual axis center were assessed using an OPD-Scan III aberrometer, and the vertical and horizontal decentration values were determined. Univariate and multivariate linear regression analyses were performed to evaluate the association between the IOL decentration and ocular biometric parameters.

RESULTS

In total, 143 eyes of 143 patients were enrolled. The mean decentration magnitude was 0.27±0.15 mm, and the decentration axis appeared at any orientation, with no orientation tendency. The horizontal and vertical decentration were -0.02±0.22 mm and 0.01±0.22 mm, respectively. Multivariate regression analysis showed that the white-to-white distance (WTW) and the magnitude of angle α were positively associated with the decentration magnitude (P<0.001, adj. R²=0.121), the horizontal angle κ and horizontal angle α were positively associated with the horizontal decentration (P<0.001, adj. R²=0.209), and the anterior chamber depth (ACD) and vertical angle κ were positively associated with the vertical decentration (P<0.001, adj. R²=0.152).

CONCLUSIONS

The IOL decentration magnitude was greater in patients with a larger WTW and a larger angle α, the horizontal decentration was greater in patients with a larger horizontal angle κ and a larger horizontal angle α, and the vertical decentration was greater in patients with a deeper ACD and a larger vertical angle κ. In these patients, premium IOLs should be implanted cautiously.

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.

Refractive error induced by intraocular lens tilt after intrascleral intraocular lens fixation

PURPOSE

To investigate the spherical shift of intraocular lens (IOL) tilt after intrascleral fixation.

METHODS

We retrospectively reviewed the medical records of patients who underwent flanged intrascleral IOL fixation with transconjunctival 25- or 27-gauge pars plana vitrectomy at the Department of Ophthalmology of the Jikei University Hospital. The minimum follow-up duration was 3 months. Second-generation anterior segment optical coherence tomography (CASIA2; TOMEY) was used to obtain the values of tilt and decentration of the intrasclerally fixated IOL and postoperative anterior chamber depth. We investigated the relationship between refractive error and various parameters, such as IOL tilt and decentration, axial length, and keratometry. In addition to our clinical investigation, we conducted optical simulations using Zemax to evaluate the spherical shift of the IOL tilt by means of the through-focus response and change in spherical equivalent power.

RESULTS

The study involved 72 eyes of 67 patients. The degree of IOL tilt was correlated with the amount of refractive error (Spearman's rank correlation coefficient [CC] = - 0.32; P = 0.006). In particular, a tilt angle greater than 10° strongly affected the refractive error. The postoperative anterior chamber depth also correlated with the refractive error (CC = 0.50; P < 0.001), as opposed to decentration (CC = - 0.17; P = 0.15), axial length (CC = - 0.08; P = 0.49), and keratometry (CC = - 0.06; P = 0.64). Optical simulations also revealed a myopic shift that exponentially increased as the tilt became greater.

CONCLUSION

IOL tilts that are greater than 10° induce refractive error.

Prediction of residual astigmatism in cataract surgery at different diameter zones using optical biometry measurement

The studies for astigmatism prediction error at different diameters using optical biometry are scant. We investigated patients who underwent cataract surgery with monofocal, nontoric intraocular lens (IOL) from 2017 through 2019 in a medical center. Patients with prior refractive surgeries, corneal opacity, or surgical complications were excluded. Corneal astigmatism (CA) was measured using AL-Scan at 2.4- and 3.3-mm diameter zones and calculated using the Barrett toric calculator preoperatively and postoperatively. The mean absolute error and centroid prediction error for the two zones were computed using double-angle plots. In total, 101 eyes of 76 patients were analyzed. Mean patient age was 68.7 ± 9.3 years and mean preoperative CA power was 0.7 ± 0.5 D. The overall centroid prediction error a 3.3 mm (0.09 ± 0.58 D@25) was significantly lower than that at 2.4 mm (0.09 ± 0.68 D@87) on the X-axis (P = 0.003). The 3.3-mm measurement also had a lower centroid prediction error than the 2.4-mm did for eyes with against-the-rule (ATR) and oblique astigmatism (P = 0.024; 0.002 on X-axis, respectively). The 3.3-mm measurement provided a more accurate CA estimation than the 2.4-mm did, particularly for ATR astigmatism. Diameter zone and astigmatism type should be considered crucial to precise astigmatism calculation.

Surgical Correction for Late Postoperative Subluxation of a Diffractive Optic Multifocal IOL, Capsule Bag and Capsule Tension Ring Complex: Case Report

Diffractive optic intraocular lenses (IOLs) require near perfect centration for best performance. A patient with a multifocal IOL and pseudoexfoliation developed late marked subluxation of the capsule bag, capsule tension ring and multifocal IOL complex. The surgical challenge was to fixate and recenter the diffractive optic IOL in order to restore normal quality vision; traditional surgical methods are not adequate for repositioning IOLs of this nature. A unique surgical plan that included three-point radially oriented suture fixation of an existing standard capsule tension ring (CTR) was conceived and was successful in achieving the patient’s goal of maintaining spectacle independence by returning his vision to previous levels with a well-centered multifocal IOL.

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 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 (1mm) 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 Strehl ratio (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 1mm: 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 Strehl ratio (mean) with 3.0 mm aperture was 0.829/0.543/0.397 and with 4.5 mm aperture 0.259/0.145/0.192. Tilted by 5 degree: 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 Strehl ratio (mean) with 3.0 mm aperture 0.539/0.478/0.514 and with 4.5 mm aperture 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.

The Influence of Angle Alpha, Angle Kappa, and Optical Aberrations on Visual Outcomes after the Implantation of a High-Addition Trifocal IOL

The aim of our investigation was to examine the possible correlations between optical aberrations, angle kappa, angle alpha, and visual outcomes following cataract surgery. In total, 56 eyes of 28 patients were implanted with the Liberty 677MY trifocal intraocular lens (IOL). Pre- and postoperative higher-order aberrations, coma, astigmatism, angle alpha, and angle kappa were registered, along with uncorrected and corrected visual acuities at multiple distances. Visual acuity and contrast sensitivity defocus curves were plotted, and the areas under the curve were calculated 1 and 3 months postoperatively. Excellent visual outcomes were found at all distances. Patients reported low levels of dysphotopsia, and 96.4% of patients achieved complete spectacle independence. While angle kappa significantly decreased during cataract surgery (p = 0.0007), angle alpha remained unchanged (p = 0.5158). Angle alpha correlated with postoperative HOAs and had a negative impact on near vision (p = 0.0543). Preoperative corneal HOA and coma had a strong adverse effect on future intermediate and near vision. Residual astigmatism significantly affected postoperative intermediate vision (p = 0.0091). Our results suggest that angle kappa is not an optimal predictive factor for future visual outcomes, while angle alpha and the preoperative screening of optical aberrations might help patient selection prior to multifocal IOL implantation.

Influence of anterior capsulorhexis shape, centration, size, and location on intraocular lens position: finite element model

PURPOSE

To evaluate the influence of anterior capsulorhexis shape, dimension, and eccentricity on intraocular lens (IOL) position.

SETTING

Laboratory investigation.

DESIGN

Computational model.

METHODS

A finite element model of the human crystalline lens capsule and zonule was created and the anterior capsule opened to simulate centered and decentered circular and elliptic rhexis. The model calculated capsular bag stress, IOL rotation, tilt, decentration, and vaulting, related to both capsular landmarks (absolute) and a reference IOL position defined as that obtained with a 5.0 mm circular and centered rhexis.

RESULTS

Mean von Mises stress along the IOL major z-axis was significantly higher than that along the perpendicular x-axis in all cases (P < .001), both at the equator and at the rhexis edge. Stress at the equator was always greater than that at the rhexis edge (P < .001) regardless of the rhexis shape and position. As rhexis eccentricity increased, the stress difference between the z- and x-axes increased. Absolute IOL tilt (range 10-1 to 10-7 degrees), decentration (10-3 to 10-7 mm), rotation (10-2 to 10-3 degrees), and vaulting (10-1 mm) were negligible from an optical standpoint, but all of them were significantly greater for decentered rhexis (both round and elliptic) compared with centered (P < .05).

CONCLUSIONS

Anterior capsulorhexis irregularity and/or eccentricity increase IOL tilt, decentration, rotation, and vaulting in a numerically significant but optically negligible way. Von Mises stress is much greater at the capsular bag equator compared with the rhexis edge and highly asymmetrically distributed in all cases. Stress asymmetry may influence postoperative biologic processes of capsular bag shrinking and further IOL tilting or decentration.

Refractive Outcomes after Cataract Surgery

A post-operative manifest refractive error as close as possible to target is key when performing cataract surgery with intraocular lens (IOL) implantation, given that residual astigmatism and refractive errors negatively impact patients’ vision and satisfaction. This review explores refractive outcomes prior to modern biometry; advances in biometry and its impact on patients’ vision and refractive outcomes after cataract surgery; key factors that affect prediction accuracy; and residual refractive errors and the impact on visual outcomes. There are numerous pre-, intra-, and post-operative factors that can influence refractive outcomes after cataract surgery, leaving surgeons with a small “error budget” (i.e., the source and sum of all influencing factors). To mitigate these factors, precise measurement and correct application of ocular biometric data are required. With advances in optical biometry, prediction of patient post-operative refractory status has become more accurate, leading to an increased proportion of patients achieving their target refraction. Alongside improvements in biometry, advancements in microsurgical techniques, new IOL technologies, and enhancements to IOL power calculations have also positively impacted patients’ refractory status after cataract surgery.

Evaluation of Decentration, Tilt and Angular Orientation of Toric Intraocular Lens

Purpose

The aim of this study was to develop software for the universal objective evaluation of factors influencing intraocular correction of astigmatism, such as decentration, tilt, axial position and angular orientation the toric intraocular lens (IOL).

Patients and Methods

Software was developed using the MS Visual Studio environment. The analysis was presented using images of 67 eyes with an implanted IOLs of the SN6ATx model series. Decentration and angular position of the lens were obtained from images of the anterior segment of the eye, using a Visucam unit. Tilt was measured on tomographic images from OCT Avanti (in meridian of highest tilt and perpendicular meridian) and preoperative biometry parameters of eye (axial length, anterior chamber depth – ACD, ocular lens thickness – LT, limbus diameter and mean keratometry value) including postoperative anterior chamber depth (pACD) were measured using Lenstar LS900.

Results

Applying the software methodology to the evaluation of individual toric IOL parameters, the following results were obtained: mean decentration 0.25 ± 0.17 mm which was observed in 61.19% of eyes, mean misalignment to the planned axis equal to 3.8 ± 3.6 degrees, mean highest inclination equal to 3.7 ± 1.2 degrees and mean difference of pACD and ACD was equal to 1.46 ± 0.31 mm. There was only a weak nonsignificant correlation between preoperative ACD versus decentration and tilt of IOL or a weak significant correlation between preoperative LT and both decentration and misalignment of IOL.

Conclusion

The use of the presented methodology for determining the positional parameters of the toric IOL provided comparable results with the results of recent studies. Software design can be considered as a suitable alternative to previously published techniques, with the significant advantage of the possibility of using universal input images, their graphical editing and especially the possibility of comprehensive analysis of all parameters.

[Refractive outcomes of out-of-the-bag intraocular lens implantation]

For the moment, the refractive outcomes of out-of-the-bag intraocular lens (IOL) implantation remain insufficiently studied.

PURPOSE

To study and compare the refractive outcomes of retropupillary implantation of an iris-claw lens and transscleral suture fixation of IOL in complicated phacoemulsification.

MATERIAL AND METHODS

The study included 70 patients (73 eyes) after complicated phacoemulsification in combination with grade 2 lens subluxation. The first group included 36 patients (39 eyes) who underwent complicated phacoemulsification using torsional ultrasound and retropupillary implantation of an iris-claw lens. The second group included 34 patients (34 eyes) after complicated phacoemulsification using torsional ultrasound and transscleral suture fixation of an elastic hydrophobic IOL. In the postoperative period we performed a comparative evaluation of uncorrected visual acuity and best corrected visual acuity, the average absolute error of IOL optical power calculation, the precision of postoperative refraction within ±0.5 diopters, the degree of induced astigmatism, and the tilt of the IOL.

RESULTS

At three months after surgery uncorrected visual acuity of 0.8-1.0 was achieved in 33.3% of cases in the first group and 17.6% in the second group, the average absolute error of IOL optical power calculation was 0.34±0.08 diopters in the first group and 0.63±0.19 diopters in the second group, the precision of postoperative refraction within ±0.5 diopters was 94.9% in the first group and 85.3% in the second group, the tilt of the IOL was 0.69±0.21° in the first group and 3.19±0.97° in the second group (p<0.05). There were no significant differences in best corrected visual acuity and the degree of induced astigmatism 3 months after surgery.

CONCLUSION

Implantation of an iris-claw lens in the course of complicated phacoemulsification in lens subluxation significantly improves refractive outcomes of the implantation in comparison with transscleral IOL fixation.

Measurement of tear resistance after manual capsulorhexis and femtosecond laser-assisted capsulotomy of crystalline lenses

Background

In this study, the tear resistance of porcine lens capsules after continuous curvilinear capsulorhexis (CCC) and femtosecond (fs)-laser-assisted capsulotomy for cataract surgery (FLC) with different laser parameters is measured with a custom-made testing setup.

Methods

Forty-five fresh porcine lenses were randomly chosen for CCC (n = 15) or FLC 1 (n = 15) and FLC 2 (n = 15). The FLC 1-group was treated with smaller spot distances than the FLC 2-group. The force necessary to break the opening of the anterior capsule and the maximum displacement were measured.

Results

The mean tear resistance of the CCC-group (150 ± 70 mN) was higher than that of the FLC 1-group (60 ± 20 mN) and the FLC 2-group (30 ± 20 mN).

Conclusion

It could be shown that CCC leads to a significantly higher tear resistance of the opening than FLC in porcine lenses. The femtosecond laser group demonstrated that smaller spot distances lead to a higher tear resistance.

EFFECT OF DECENTRATION ON THE QUALITY OF VISION: A COMPARISON BETWEEN ASPHERIC BALANCE CURVE DESIGN AND POSTERIOR ASPHERIC DESIGN INTRAOCULAR LENSES

PURPOSE

To study the effect of decentration on the quality of vision in two 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.).

SETTING

Advanced Eye Centre, PGIMER, Chandigarh, India.

DESIGN

Randomised Prospective Trial using Random number table.

METHODS

Eighty-five eyes were randomized to Group 1 (Vivinex XY1) and Group 2 (Acrysof IQ) with 40 and 45 eyes respectively. The HOA profile, Strehl's ratio, decentration of IOL from the visual axis (DVA) and the geometric axis (DGA), angle Alpha and Kappa were recorded on the iTrace aberrometer and contrast sensitivity was measured using the Functional Acuity Contrast Test at 12 weeks post-surgery.

RESULTS

The mean values of the Strehl's ratio (p=0.48) and the HOA's (p=0.12) of both IOLs were comparable. The HOA's gradually increased with increasing DVA for both lenses at 3, 4 and 5mm pupil sizes. On comparing the HOA's with the DGA a statistically insignificant positive correlation was observed. The Strehl's ratio did not deteriorate with increasing angle alpha in the Vivinex XY1 group, however worsened in the Acrysof IQ group. The contrast sensitivity was comparable in both the IOLs except at 1.5cpd under photopic conditions where Acrysof IQ was better.

CONCLUSIONS

Decentration of the lens is best measured with respect to the visual axis. In eyes with a large alpha, the ABC design induced lesser HOA's and maintained a better Strehl's ratio.

Three-Dimensional Reconstruction and Swept-Source Optical Coherence Tomography for Crystalline Lens Tilt and Decentration Relative to the Corneal Vertex

Purpose

To investigate crystalline lens tilt and decentration with respect to the corneal vertex (CV) using swept-source optical coherence tomography (SS-OCT) combined with three-dimensional (3D) reconstruction.

Methods

Thirty consecutive patients with cataract (30 right eyes) were included in this prospective, observational, pilot case series study. SS-OCT anterior segment images and 3D reconstructions were used for data analysis.

Results

The mean distance between the central points of crystalline lens plane and limbus plane was approximately 0.33 ± 0.18 mm. The distance of the center of the limbus plane relative to the CV was approximately 0.31 ± 0.14 mm, which approximated the distance of the center of the crystalline lens plane relative to the CV at 0.33 ± 0.20 mm (P = 0.354). However, the centers of the limbus and crystalline planes were not in the same quadrant in 80% of eyes (24/30). Moreover, the crystalline lens tilted by approximately 4.16° ± 1.97° relative to the CV.

Conclusions

The center of the limbus plane was not consistent with that of the crystalline lens plane. The tilt and decentration of the crystalline lens were natural phenomena.

Translational Relevance

The SS-OCT technology combined with 3D reconstruction was useful for quantifying the tilt and decentration of the crystalline lens. The definition of angle alpha used for premium IOL screening should be updated.

Comparison of Clinical Outcomes, Visual Quality and Visual Function of Two Presbyopia-Correcting Intraocular Lenses Made from the Same Material, but with Different Design and Optics

This semi-prospective, parallel, comparative investigation evaluated the clinical outcomes and quality of vision (contrast sensitivity, visual function, dysphotopsia, spectacle use, overall satisfaction) after mono- or bilateral implantation of two presbyopia-correcting intraocular lenses (IOL)—the Liberty^® 677MY or the AT LISA^® tri 839M—in 50 eyes of 25 cataract patients. Clinical outcomes were assessed 3 and 12 months postoperatively. Eighty-nine percent of eyes implanted with the Liberty IOL and 59% of eyes implanted with the AT LISA IOL achieved a refractive outcome ±0.5 diopters of the target (emmetropia). Refractive outcomes were stable with both lenses. The proportions of eyes with 20/20 uncorrected distance visual acuity (UDVA) and 20/20 uncorrected near visual acuity (UNVA) were higher in the Liberty group than in the AT LISA group (UDVA: 56% vs. 41%; UNVA: 83% vs. 66%). Optical quality assessment results were comparable for the two IOLs. Superior photopic contrast sensitivity was found with the Liberty lens. The rate of Nd:YAG capsulotomy at the 12-month follow-up was 16.7% in the Liberty group and 40.6% for the AT LISA IOL. Considering that both lenses are made from the same material, we propose that the noted differences in clinical outcomes may derive from differences in design and optical surface between the two IOLs.

Individual design of aberration-free intraocular lenses

An analytical tool capable of easily calculating a new aspheric intraocular lens (IOL) (shape factor, aspherization) chosen to be designed as "aberration free" in terms of spherical aberration and/or coma is reported. In terms of retinal image quality, the theoretical performances given by the new proposed IOLs compare well with commercial IOLs.

Rotational stability of modified toric intraocular lens

We evaluated the rotational stability of a new toric intraocular lens (IOL), HOYA XY-1 toric IOL that is an improved version of HOYA 355 toric IOL, with longer overall length (13.0 mm vs. 12.5 mm), shortened unfolding time, and texture processing of the surface of haptics. Data from 193 eyes of 165 patients (76.4 ± 8.3 years old) with preoperative corneal astigmatism exceeding 0.75 diopters who had undergone phacoemulsification and toric IOL implantation were collected and analyzed. Corneal astigmatism, refractive astigmatism, and uncorrected (UDVA) and corrected distance visual acuity (CDVA) were evaluated before and 1 day, 1 week, and 1 month after surgery. The degree of IOL decentration, IOL tilt, and toric axis misalignment was assessed at 1 day and 1 month postoperatively. Fifty eyes received AcrySof toric IOL, 51 eyes TECNIS toric IOL, 46 eyes HOYA 355 toric IOL, and 46 eyes HOYA XY-1 toric IOL. The amount of axis misalignment from the intended axis was significantly different among IOLs (p = 0.004, one-way ANOVA), and HOYA XY-1 showed significantly less amount of axis misalignment than TECNIS (p = 0.020, Tukey’s multiple comparison) and HOYA 355 (p = 0.010). The proportion of eyes that showed axis misalignment <10° at 1 month postoperatively was significantly higher with HOYA XY-1 toric IOL than with other toric IOLs (χ² test, p = 0.020). HOYA XY-1 toric IOL, the modified version of HOYA 355 toric IOL, showed excellent rotational stability in comparison with other models of toric IOLs.

Optical aberrations in three different intraocular lens designs of a same platform

PURPOSE:

To compare internal optical aberrations between three different intraocular lenses (IOL) of the same Tecnis platform: monofocal ZCB00, multifocal ZMB00, and enlarged depth-of-focus (EDoF) Symfony ZXR00.

METHODS:

We included in this study 236 eyes of 118 patients who had been bilaterally implanted either with the monofocal, the multifocal, or the EDoF IOL. They were examined with the K1-RW wavefront analyzer (Topcon Medical Systems) 2 months after surgery. Patients with any ocular pathology were excluded from the study. Only high-order aberrations (HOA) of the third and fourth orders of the Zernike polynomials were considered.

RESULTS:

Forty-three patients (86 eyes) were implanted with the monofocal IOL, 45 patients (90 eyes) with the ZMB00 IOL, and 30 patients (60 eyes) with the EDoF Symfony IOL. Mean age was 62.42 ± 7.38, 63.60 ± 6.01, and 64.74 ± 5.84 years, respectively. Mean axial length was 23.37 ± 1.00, 23.49 ± 1.00, and 23.54 ± 0.73 mm, respectively. For a 6-mm pupil, internal total HOA in the monofocal group was 1.01 ± 1.75 μm; in the bifocal group was 1.35 ± 2.12 μm; and in the Symfony group was 0.72 ± 0.63 μm. No optical aberration differences were found among the three groups (P > 0.05).

CONCLUSION:

There are no differences regarding internal optical aberrations between these three IOLs when analyzing them with optical aberrometry. Patients’ pupil size should be considered for the selection of the most appropriate IOL to be implanted, because despite a same optical platform, every IOL implies a different increase of HOA with larger pupil sizes.

Theoretical Effect of Coma and Spherical Aberrations Translation on Refractive Error and Higher Order Aberrations

(1) Background: The purpose of the study is to present a simple theoretical account of the effect of translation of coma and spherical aberrations (SA) on refractive error and higher order aberrations. (2) Methods: A computer software algorithm was implemented based on previously published methods. The effect of translation (0 to +1 mm) was analyzed for SA (0 to +2 µm) and coma (0 to +2 µm) for a circular pupil of 6 mm, without any rotation or scaling effect. The relationship amongst Zernike representations of various aberrations was analyzed under the influence of translation. (3) Results: The translation of +0.40 µm of SA (C[4,0]) by +0.25 mm with a pupil diameter of 6mm resulted in induction of tilt (C[1,1]), −0.03D defocus (C[2,0]), +0.03D astigmatism (C[2,2]) and +0.21 µm coma (C[3,1]). The translation of +0.4 µm of coma (C[3,1]) by +0.25 mm with a pupil diameter of 6 mm resulted in induction of tilt (C[1,1]), −0.13D defocus (C[2,0]) and +0.13D astigmatism (C[2,2]). A theoretical quantitative relationship between SA, coma, astigmatism and defocus is presented under the influence of translation. (4) Conclusion: The results can act as a guide for the clinician, in order to readily assess theoretical impact of wavefront map translation from pupil center to the visual axis. The resultant refractive coupling has to be taken into consideration especially when treating eyes with an abnormal corneal shape and/or large pupil center to corneal vertex chord.