Risk factors for refractive error after cataract surgery: Analysis of 282 811 cataract extractions reported to the European Registry of Quality Outcomes for cataract and refractive surgery

Refractive tolerance in the use of monofocal intraocular lenses enhanced with new aspheric design

PURPOSE

To evaluate the refractive tolerance in eyes with enhanced monocular intraocular lens (IOL) with a new aspheric design.

METHODS

This study included two assessments. Clinical records of consecutive eyes with conventional monofocal IOL (SY60WF, Alcon) were retrospectively reviewed, and changes in uncorrected distance visual acuity (UDVA) with myopic and hyperopic refractive errors were evaluated using segmented regression analysis. Next, in 39 eyes of 39 cataract patients who received an enhanced monofocal IOL (NSP-3, Nidek), UDVA, refractive error, and photopic and mesopic contrast sensitivities were examined at one-three months postoperatively. Changes in the UDVA with refractive error were evaluated in the same manner. With resultant segmented regression lines, ranges of UDVA of 0.20 logMAR or better were obtained as refractive tolerances.

RESULTS

The clinical records of 717 eyes of 551 patients with SY60WF were analyzed. Segmented regression analysis revealed a breakpoint in emmetropia and UDVA degradation myopically and hyperopically. The refractive tolerance was 2.03 D, while it was 0.73 D on the myopic side. In the prospective study, there was a breakpoint at -1.088 D, where there was a relatively flat slope between the breakpoint and emmetropia, then UDVA steeply degraded. Refractive tolerance on the myopic side was 1.12 D. There was no significant degradation in the photopic/mesopic contrast sensitivity.

CONCLUSION

Enhanced monofocal IOLs provided wider myopic refractive tolerance, in which UDVA of 0.2 logMAR or better would be anticipated between emmetropia and myopic error of -1.12 D.

Prospective Comparison of Clinical Outcomes After Bilateral Implantation of Diffractive Trifocal Extended Depth-of-Focus and Diffractive Trifocal Hydrophobic Intraocular Lenses

PURPOSE

To compare clinical outcomes for patients implanted with either FineVision HP or FineVision Triumf intraocular lenses (IOL) (Beaver-Visitec International, Inc) following cataract surgery.

METHODS

Twenty-six patients bilaterally implanted with the HP IOL and 27 patients with the Triumf IOL were followed up for 6 months in a prospective randomized study. Refraction, uncorrected and corrected distance visual acuity (CDVA), uncorrected and distance-corrected intermediate visual acuity (DCIVA), and uncorrected and distance-corrected near visual acuity (DCNVA) were evaluated. Defocus curves and contrast sensitivity were also measured. Patient-reported outcomes were assessed using the National Eye Institute Visual Function Questionnaire 25, and adverse events were registered.

RESULTS

Ninety-four percent of the eyes in both groups were within ±1.00 diopter (D) of spherical equivalent. All of the patients had 20/20 or better binocular CDVA in both groups and 96% and 100% had 20/25 or better binocular CDIVA in the Triumf and HP IOL groups, respectively, being reduced to 32% and 91.7% for DCNVA, respectively. Differences between groups were statistically significant from -2.00 to -4.50 D with better visual acuity outcomes for the HP IOL group (P < .01). Better monocular photopic contrast sensitivity was found for the Triumf IOL group at 12 and 18 cycles per degree (P < .01). There was a statistically significant increase of the overall composite score in both groups before and after surgery (P < .001). Spectacle independence was similar between groups for distance and intermediate vision but higher for the HP IOL for near vision (96% versus 75%). There were no adverse events related to the IOLs.

CONCLUSIONS

Both IOLs showed good and comparable distance and intermediate visual acuities but near vision was better for the HP IOL. This model provided higher spectacle independence for near vision. [J Refract Surg. 2025;41(3):e102-e113.].

Innovative Polymeric Biomaterials for Intraocular Lenses in Cataract Surgery

Intraocular lenses (IOLs) play a pivotal role in restoring vision following cataract surgery. The evolution of polymeric biomaterials has been central to addressing challenges such as biocompatibility, optical clarity, mechanical stability, and resistance to opacification. This review explores essential requirements for IOL biomaterials, emphasizing their ability to mitigate complications like posterior capsule opacification (PCO) and dysphotopsias while maintaining long-term durability and visual quality. Traditional polymeric materials, including polymethyl methacrylate (PMMA), silicone, and acrylic polymers, are critically analyzed alongside cutting-edge innovations such as hydrogels, shape memory polymers, and light-adjustable lenses (LALs). Advances in polymer engineering have enabled these materials to achieve enhanced flexibility, transparency, and biocompatibility, driving their adoption in modern IOL design. Functionalization strategies, including surface modifications and drug-eluting designs, highlight advancements in preventing inflammation, infection, and other complications. The incorporation of UV-blocking and blue-light-filtering agents is also examined for their potential in reducing retinal damage. Furthermore, emerging technologies like nanotechnology and smart polymer-based biomaterials offer promising avenues for personalized, biocompatible IOLs with enhanced performance. Clinical outcomes, including visual acuity, contrast sensitivity, and patient satisfaction, are evaluated to provide an understanding of the current advancements and limitations in IOL development. We also discuss the current challenges and future directions, underscoring the need for cost-effective, innovative polymer-based solutions to optimize surgical outcomes and improve patients' quality of life.

Refractive Predictability of Two Intraocular Lens Power Formulas in Long, Medium, and Short Eyes Using a Swept Source Optical Coherence Tomography Biometer

Purpose

To compare the refractive predictability of Argos measurements with Barrett Universal II (BUII) and Barrett True Axial Length (BTAL) formulas in a large sample of long, medium, and short axial length (AL) eyes.

Methods

A retrospective chart review identified 445 eyes of 247 patients for inclusion. The Argos was used for preoperative biometry, and BUII formula for intraocular lens (IOL) power calculations. Back calculations were performed using data from the Argos for the BTAL formula. Data were collected for postoperative absolute prediction error (APE), refractive outcomes, and monocular uncorrected and distance corrected visual acuities at distance (UDVA, CDVA).

Results

Overall, mean APE was 0.36 ± 0.33 D for BUII and for 0.34 ± 0.32 D BTAL (p = 0.04). In short AL eyes, mean APE was 0.45 ± 0.37 D for BUII and for 0.37 ± 0.31 D BTAL (p < 0.001). No significant differences between BUII and BTAL were identified for long AL or medium AL eyes. The percentages of eyes with APE of 0.5 D or less in long, medium, and short eyes were 79%, 79% and 51%, respectively, for BUII and 82%, 78% and 69%, respectively, for BTAL.

Conclusion

The prediction accuracies were high with both the BUII and BTAL formulas in long, medium, and short eyes, leading to excellent refractive outcomes. The BTAL formula may have lower absolute prediction error in short eyes compared to BUII.

Refractive outcomes using Barrett formulas and patient characteristics of cataract surgery patients with and without prior LASIK/PRK

PURPOSE

The goal of this study is to describe characteristics of cataract surgery patients who previously underwent laser in situ keratomileusis/photorefractive keratectomy (LASIK/PRK) in comparison to non-LASIK/PRK cataract surgery patients including psychiatric comorbidities, as well as describe refractive prediction error after cataract surgery while accounting for axial length (AL) using the Barrett True-K and Barrett Universal II formulas.

METHODS

This was a retrospective study of patients from the University of Colorado Cataract Outcomes Registry. The primary outcomes were refraction prediction error (RPE), mean absolute RPE, and median absolute RPE. Outcomes were stratified by five axial length groups. Univariate and multivariate models for RPE were stratified by the AL group.

RESULTS

Two hundred eighty-one eyes with prior LASIK/PRK and 3101 eyes without are included in the study. Patients with prior LASIK/PRK were significantly younger: 67.0 vs 69.9 years, p < 0.0001. The LASIK/PRK group had significantly better mean pre-operative BCVA in comparison to the non-LASIK group, logMAR 0.204 vs logMAR 0.288, p = 0.003. The LASIK/PRK group had significantly lower rates of cardiovascular disease (18.5% vs 29.3%, p < 0.001), hypertension (49.1% vs 59.3%, p < 0.012), and type 2 diabetes (10.7% vs 26.0%, p < 0.001), and no significant difference in psychiatric disease. The absolute RPE was higher for the LASIK group for all ALs, but only significantly higher for eyes with AL less than 25 mm.

CONCLUSION

Patient eyes with prior LASIK/PRK surgery undergoing cataract surgery were significantly younger, had significantly less comorbidities, and a significantly better pre-operative BCVA. Using the Barrett formulas, absolute prediction error for eyes with longer ALs was not significantly worse for LASIK/PRK eyes than those without and the difference was smaller for eyes with longer AL.

Comparative Analysis of Refractive Outcomes Following Cataract Surgery Using IOL Master 500 and IOL Master 700 Biometry Devices: A Retrospective Analysis

Background: This study aims to compare the refractive outcomes of cataract surgery using two different biometry devices, the IOL Master 500 and IOL Master 700, and to investigate the influence of patient-related factors on these outcomes. Methods: In this retrospective study, we analyzed data from 2994 eyes that underwent cataract surgery. Multiple linear regression analyses were performed to examine the impact of the biometry device (IOL Master 500 or IOL Master 700), patient age, time elapsed between biometry and surgery, gender, and insurance status, as well as biometric parameters (anterior chamber depth, axial length, and corneal curvature), on postoperative refractive outcomes, specifically the deviation from target refraction. Results: The choice of the IOL Master device did not result in a statistically significant difference between the two devices (p = 0.205). Age (p = 0.006) and gender (p = 0.001) were identified as significant predictors of refractive outcomes, with older patients and males experiencing slightly more hyperopic outcomes compared to younger patients and females, respectively. The time elapsed between biometry and surgery and insurance status did not significantly influence the refractive outcomes. Conclusions: Our study, supported by a large cohort and a diverse group of patients representing typical anatomical variants seen in cataract surgery, supports the thesis that the IOL Master 500 and IOL Master 700 can be regarded as equivalent and effective for biometry in cataract surgery. The differences between the devices were negligible. Therefore, switching between the devices is safe for bilateral patients.

Surgical Outcomes, Ocular Safety and Tolerability of Bio-Interventional Cyclodialysis with Allograft Scleral Reinforcement: Clinical Experience of More than 240 Cases

Background: To report the surgical safety of reinforced bio-interventional cyclodialysis with scleral allograft reinforcement. Methods: This was a consecutive case series of 243 eyes with open-angle glaucoma who underwent a bio-scaffolded cyclodialysis (BSC) procedure for uveoscleral outflow enhancement using allogeneic bio-spacers to maintain patency of the internal filtration conduit. Results: 79% of the eyes underwent concomitant phacoemulsification cataract surgery prior to BSC intervention, while the remaining eyes underwent stand-alone BSC surgery. All patients had a postoperative surgical safety period of at least 30 days. There were no sight-threatening or serious ocular adverse events. There was one case of prolonged iritis beyond 30 days, which resolved with topical treatment. Two cases (0.8%) of intraoperative and five (2%) of postoperative non-sight-threatening hyphema were without clinical sequelae, which resolved with conservative management. There were 11 cases of IOP elevation and one case of numeric hypotony without maculopathy, which resolved within the study period. The rate of secondary surgical intervention for IOP control was low, and overall, IOP for the cohort improved in the postoperative period, with 78.6% of eyes achieving IOP ≤ 18 mmHg without an increase in medications. Conclusions: Allogeneic biotissue for cyclodialysis intervention demonstrates a biocompatible ocular profile as an implantable material for internal scleral reinforcement during uveoscleral outflow enhancement surgery.

EVALUATION AND MANAGEMENT OF POST-OPERATIVE COMPLICATIONS FOLLOWING CATARACT EXTRACTION AND INTRAOCULAR LENS PLACEMENT

THIS REVIEW EXPLORES POST-OPERATIVE CHALLENGES ARISING FROM CATARACT SURGERY, INCLUDING INTRAOCULAR LENS (IOL) DECENTRATION OR DISLOCATION, REFRACTIVE SURPRISES, DYSPHOTOPSIAS, AND IOL OPACIFICATIONS. IOL DECENTRATION OR DISLOCATION IS RARE, HIGHLIGHTING THE NEED FOR CAREFUL MANAGEMENT WITH MONITORING, SURGICAL REPOSITIONING OR LENS EXCHANGE TO ACHIEVE OPTIMAL VISUAL OUTCOMES. REFRACTIVE SURPRISES, ATTRIBUTED TO ERRORS IN IOL CALCULATION AND SELECTION, MAY BE MANAGED CONSERVATIVELY OR SURGICALLY, WITH THE MOST ACCURATE RESULTS ACHIEVED BY LASER VISION CORRECTION. POSITIVE AND NEGATIVE DYSPHOTOPSIAS MAY CONTINUE TO BE INTOLERABLE FOR PATIENTS, AND MAY REQUIRE LENS EXCHANGE AS WELL. IOL OPACIFICATIONS VARY BY IOL MATERIAL AND MAY BE VISUALLY SIGNIFICANT, REQUIRING LENS EXCHANGE. WE UNDERSCORE THE IMPORTANCE OF NUANCED MANAGEMENT AND PROVIDING OPTIMAL PATIENT CARE IN THE ABOVE POST-CATARACT SURGERY AND IOL IMPLANTATION COMPLICATIONS.

Outcomes After Implantation of a Trifocal Toric Intraocular Lens Using Intraoperative Aberrometry, Digital Image Tracking, and Femtosecond Laser

Purpose

To evaluate the refractive and visual acuity outcomes when using trifocal toric intraocular lenses (IOLs), femtosecond laser assisted cataract surgery (FLACS), swept-source optical coherence tomography (SS-OCT) biometry, digital image tracking (DT) and intraoperative aberrometry (IA).

Methods

This prospective, single-arm, observational study of refractive and visual outcomes included 40 eyes of 34 subjects. Preoperative biometry was performed with the Argos, FLACS and digital marking with LenSx, and IA and DT with ORA. Eyes were implanted with the Clareon PanOptix toric IOL. Study outcome measures included absolute prediction error, residual refractive astigmatism, and monocular uncorrected and distance corrected visual acuity at distance (UDVA, CDVA), intermediate (UIVA, DCIVA; 60cm), and near (UNVA, DCNVA; 40cm).

Results

Mean absolute prediction error (spherical equivalent) was 0.43 ± 0.36 D, and the percentage of eyes with absolute prediction error ≤ 0.5 D was 72.5% (29/40 eyes). Mean residual astigmatism was 0.36 ± 0.65 D, and the percentage of eyes with residual astigmatism ≤ 0.5 D was 80% (32/40 eyes). Monocular UDVA, UIVA, and UNVA was 20/25 or better in 75%, 64%, and 87% of eyes respectively. Monocular CDVA, DCIVA, and DCNVA was 20/25 or better in 95%, 64%, and 87% of eyes respectively.

Conclusion

The results of this study suggest that trifocal toric implantation with SS-OCT, FLACS, DT, and IA can provide excellent refractive and visual outcomes.

Risk Factors Associated with Unexpected Refractive Outcomes in Uveitic Cataract Surgery

OBJECTIVE

Assess refractive outcomes following uveitic cataract surgery and identify factors associated with deviations from the target refractive goal.

METHODS

A multicenter retrospective chart review was performed for 216 subjects with uveitis undergoing cataract surgery. Prediction error was calculated and tested for association with demographic and clinical characteristics using single variable and multiple regression analysis.

RESULTS

39.8% of eyes deviated from the intended refractive target by at least 0.5 diopters (D). The mean prediction error was 0.56 ± 0.67 D. Younger age (p = 0.042), preoperative inflammatory corneal findings (keratic precipitates and/or band keratopathy) (p = 0.0004), and poorer postoperative visual acuity (p = 0.0054) were associated with a deviation from the intended refractive target by at least 1 D.

CONCLUSIONS

A higher percentage of eyes undergoing uveitic cataract surgery deviated from the intended refractive target when compared to reported refractive outcomes in normal subjects. Younger age, preoperative inflammatory corneal sequelae, and poorer postoperative visual acuity were associated with this outcome.

Visual and refractive outcomes of opposite clear corneal incision combined with rotationally asymmetric multifocal intraocular lens implantation

Purpose

To evaluate the visual and refractive outcomes of astigmatic cataract patients following opposite clear corneal incision (OCCI) combined with rotationally asymmetric multifocal intraocular lens (IOL) implantation.

Setting

Department of Ophthalmology, Zhongshan Hospital (Xiamen), Fudan University, People's Republic of China.

Design

Retrospective cohort study.

Methods

This study comprised 58 cataract eyes of 54 patients with corneal astigmatism who underwent phacoemulsification and rotationally asymmetric multifocal IOL implantation which received either OCCI (OCCI group) or a single clear corneal incision (SCCI group). The follow-up period was 3 months after surgery. Distance, intermediate and near visual acuity, refractive outcomes, and corneal anterior keratometry were compared between the two groups. Vector analysis was used to evaluate astigmatism correction.

Results

Three months after surgery, the distance, intermediate and near visual acuity, and sphere remained comparable between the two groups, but a significant difference was detected in residual astigmatism and anterior corneal keratometric astigmatism. In the OCCI group, the residual astigmatism and keratometric astigmatism were -0.60 ± 0.29 D and 0.59 ± 0.28 D, respectively, which were lower than those in SCCI groups (-1.18 ± 0.47 D and 1.15 ± 0.45 D, both p < 0.05). In vector analysis, the difference vector (DV), angle of error (AoE), absolute AoE, index of success (IoS) and correction index (CI) were statistically significantly different between the two groups (p < 0.05).

Conclusion

OCCI combined with rotationally asymmetric multifocal intraocular lens implantation showed predictable and desirable efficacy in treating cataract patients with astigmatism.

Effect of residual sphere on uncorrected visual acuity and satisfaction in patients with monofocal and multifocal intraocular lenses

PURPOSE

To assess the effect of residual sphere on vision and satisfaction in pseudophakic patients.

SETTING

Private clinics, United Kingdom.

DESIGN

Retrospective case series.

METHODS

A multivariate model evaluated the effect of 1-month residual sphere on outcomes of pseudophakic patients. Odds ratios (ORs) were calculated to assess the relative risk of not achieving ≥20/20 monocular uncorrected distance visual acuity (UDVA), ≥20/50 uncorrected near visual acuity (UNVA), and not being satisfied with vision. ORs were assessed for residual sphere -1.00 to +1.00 diopter (D) in quarter-diopter steps, using 0.00 D as a reference.

RESULTS

The analysis included 38 828 multifocal and 11 571 monofocal intraocular lenses (IOLs). The residual myopic sphere ≤-0.25 D and hyperopic sphere ≥+0.50 D had a clinically meaningful effect on UDVA. Although monofocal IOLs had an improvement in UNVA with every additional 0.25 D of myopia, the change in ORs with increasing myopia was not significant for multifocal IOLs. The mean improvement in UNVA comparing eyes with 0.00 D and -1.00 D sphere was 0.26 logMAR for monofocal and 0.03 logMAR for multifocal IOLs. Low near-addition IOLs had a slightly higher gain in UNVA with increasing myopia, but the gain was not as substantial as with monofocal IOLs. The effect of ametropia on satisfaction was more pronounced for multifocal IOLs. For every 0.25 D of residual myopia, there was >25% increase in dissatisfied patients.

CONCLUSIONS

Although myopia improved UNVA in eyes with monofocal IOL, multifocal IOLs did not benefit from residual myopia. Multifocal IOL patients desiring distance vision should be targeted closest to emmetropia, even if it means targeting slight hyperopia.

Influence of Lens Thickness on Accuracy of Kane, Hill-RBF 3.0, Barrett Universal II, Emmetropia Verifying Optical, and Pearl-DGS Formulas in Eyes with Nonhigh Myopia and High Myopia

PURPOSE

To investigate the influence of lens thickness (LT) on accuracy of Kane, Hill-RBF 3.0 Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO), and Pearl-DGS formulas in eyes with different axial lengths (AL).

METHODS

The prospective cohort study was conducted at Eye and ENT Hospital of Fudan University. Patients who had uneventful cataract surgery between March 2021 and July 2023 were recruited. Manifest refraction was conducted two-month post-surgery. Eyes were divided into 4 groups based on AL: short (<22mm), medium (22-24.5 mm), medium long (24.5-26mm) and very long (≥26mm). In each AL group, eyes were then divided into 3 subgroups based on the LT measured with IOLmaster700: thin (<4.5 mm), medium (4.5-5.0 mm), and thick (≥ 5 mm). The influence of LT on accuracy of Kane, Hill-RBF 3.0, BUII, EVO, and Pearl-DGS formulas were investigated in each AL group.

RESULTS

A total of 327 eyes from 327 patients were analyzed, with 64, 102, 73 and 88 eyes in each AL group, respectively. In eyes with AL < 24.5 mm, myopic PE was significantly associated with greater LT using all the 5 formulas (all p < 0.05). Backward stepwise multivariate regression analyses revealed that LT was an important influencing factor for PE in all 5 formulas, particularly in eyes with AL <24.5 mm. In eyes with AL <24.5 mm and LT > 5.0 mm, PE of all 5 formulas calculated with the optional parameter LT were more myopic than those calculated without LT.

CONCLUSIONS

Thicker LT was associated with more myopic PE among eyes with AL <24.5 mm when using all 5 formulas. Further optimization of current formulas is necessary, especially for eyes with short AL and thick LT.

Visual Function After Implantation of Trifocal and Trifocal Toric Intraocular Lenses Using Intraoperative Aberrometry

Purpose

To evaluate patient outcomes and visual function following trifocal and trifocal toric intraocular lens (IOL) implantation using intraoperative aberrometry at a single site in the US.

Methods

This prospective, single arm study included 21 subjects that completed 3 month follow-up. Inclusion criteria were visually significant cataract and potential post-operative visual acuity of 20/25 or better. Endpoints included postoperative prediction error, refractive outcomes, uncorrected visual acuities at distance (UDVA), intermediate (UIVA), and near (UNVA), contrast sensitivity, and subject responses on the modified Visual Function Quality of Life Questionnaire (VF-14 QOL).

Results

Binocular UDVA, UIVA, and UNVA were 20/25 or better in 100% (21/21), 100% (21/21), 90% (19/21) of subjects. The absolute prediction error was 0.50 D or less in 79% (33/42) of eyes, and 81% (34/42) and 86% (36/42) of eyes achieved ≤0.5 D of residual astigmatism and manifest refraction spherical equivalent, respectively. On the modified VF-14 QOL, driving at night, reading small print, and reading a newspaper or book were the tasks that had the lowest percentages of subjects reporting no difficulty or a little difficulty.

Conclusion

Implantation with trifocal and trifocal toric IOLs using intraoperative aberrometry can provide high refractive precision, leading to excellent visual performance and low visual task difficulty at all ranges (distance, intermediate, and near).

Tolerance to refractive error with a new extended depth of focus intraocular lens

PURPOSE

To evaluate the tolerance to refractive errors of a new purely refractive extended depth of focus (EDF) intraocular lens (IOL), TECNIS PureSee™ IOL, using preclinical and clinical metrics.

METHODS

Preclinical evaluation included computer simulations of visual acuity (sVA) and dysphotopsia profile of different IOL designs (refractive EDF, diffractive EDF, multifocal, standard, and enhanced monofocals) using an appropriate eye model with and without ±0.50 D defocus and/or +0.75 D of astigmatism. Patients bilaterally implanted with a refractive EDF (Model ZEN00V) or an enhanced monofocal (Model ICB00) IOL from a prospective, randomized study were included. At the 6-month postoperative visit, uncorrected and corrected distance vision (UDVA and CDVA), visual symptoms, satisfaction and dependency on glasses were evaluated in a subgroup of patients with absolute residual refractive error of >0.25 D in one or both eyes.

RESULTS

In the presence of defocus and astigmatism, sVA was comparable for all except the multifocal IOL design. The refractive EDF was more tolerant to myopic outcomes and maintained a monofocal-like dysphotopsia profile with defocus. Binocular logMAR UDVA was -0.03 ± 0.08 for ZEN00V and -0.02 ± 0.11 for ICB00. 100% ZEN00V and 97% ICB00 patients did not need glasses and were satisfied with their distance vision. Monocular CDVA, contrast sensitivity and visual symptoms were also similar between both groups.

CONCLUSIONS

The clinical outcomes of the refractive EDF IOL demonstrated high quality distance vision and dysphotopsia comparable to a monofocal IOL, even in the presence of refractive error, thus matching the design expectations of the EDF IOL.

Toric intraocular lens: A literature review

Toric intraocular lenses (IOLs) are universally recommended in cataract cases with preoperative corneal astigmatism ≥1.5 D. An optimal surgical outcome depends on careful patient selection, complete preoperative evaluation, accurate IOL power calculation, precise marking of the axis, meticulous intraoperative approach, and methodical postoperative care. Understanding the importance of posterior corneal astigmatism, surgically induced astigmatism, and effective lens position in IOL power calculation and newer techniques to measure them directly have resulted in better postoperative refractive outcomes. We present a brief overview of toric IOLs along with the preoperative evaluation, IOL power calculation, different marking methods, intraoperative approach, and postoperative outcomes. Functional and anatomical outcomes, including uncorrected visual acuity, residual refractive astigmatism, and postoperative IOL misalignment, which have been reported for both toric IOLs and multifocal toric IOLs, are reviewed.

Prevalence and associated factors of refractive error among adults in South Ethiopia, a community-based cross-sectional study

INTRODUCTION

The increasing prevalence of refractive error has become a serious health issue that needs serious attention. However, there are few studies regarding the prevalence and associated factors of refractive error at the community level in Ethiopia as well as in the study area. Therefore, providing updated data is crucial to reduce the burdens of refractive error in the community.

OBJECTIVE

To assess the prevalence and associated factors of refractive error among adults in Hawassa City, South Ethiopia, 2023.

METHOD

A community-based cross-sectional study was conducted on 951 adults using a multistage sampling technique from May 8 to June 8, 2023, in Hawassa City, South Ethiopia. A pretested, structured questionnaire combined with an ocular examination and a refraction procedure was used to collect data. The collected data from the Kobo Toolbox was exported to a statistical package for social sciences for analysis. Binary and multivariable logistic regression analyses were performed. A P-value of less than 0.05 was considered statistically significant in the multivariable analysis.

RESULT

A total of 894 study participants were involved in this study with a 94.1% response rate. The prevalence of refractive error was 12.3% (95% CI: 10.2, 14.5%). Regular use of electronic devices (adjusted odds ratio = 3.64, 95% CI: 2.25, 5.91), being diabetic (adjusted odds ratio = 4.02, 95% CI: 2.16, 7.48), positive family history of refractive error (adjusted odds ratio = 2.71, 95% CI 1.59, 4.61) and positive history of cataract surgery (adjusted odds ratio = 5.17, 95% CI 2.19, 12.4) were significantly associated with refractive error.

CONCLUSION AND RECOMMENDATION

The overall magnitude of refractive error in our study area was high. Regular use of electronic devices, being diabetic, positive family history of refractive error, and a positive history of cataract surgery were associated with refractive error.

Refractive outcomes of immediately sequential bilateral cataract surgery in eyes with long and short axial lengths

PURPOSE

To report the refractive outcomes of long (≥25.00 mm) and short (≤22.00 mm) axial length (AL) eyes undergoing immediately sequential bilateral cataract surgery (ISBCS).

METHODS

In this retrospective cohort study, patients who underwent ISBCS were identified and eyes of patients with bilateral long and short ALs were included. Pre- and postoperative biometry, autorefraction, and ocular comorbidities or complications were recorded. The primary outcome was the mean refractive prediction error.

RESULTS

Thirty-seven patients (74 eyes) with long ALs and 18 patients (36 eyes) with short ALs were included. The means ± standard deviations of the ALs were 26.40 ± 1.38 mm and 21.44 ± 0.46 mm in the long and short AL groups, respectively. In long AL eyes, the mean absolute error from the biometry-predicted refraction was - 0.16 ± 0.46 D, corresponding to 74% of eyes achieving a refraction within ±0.50 D of the predicted value. In short AL eyes, the mean absolute error was - 0.63 ± 0.73 D, corresponding to 44% of eyes achieving a refraction within ±0.50 D of the predicted value. Eight (44.4%) patients with short AL eyes had a myopic deviation greater than ±0.50 D from the predicted result in both eyes.

CONCLUSIONS

Compared to patients with long AL eyes, ISBCS in patients with short ALs had a wider variance in refractive outcome and a lower rate of achieving a postoperative refraction within ±0.50 D of the predicted target.

Update on Femtosecond Laser-Assisted Cataract Surgery: A Review

The advent of femtosecond lasers has resulted in a new standard in cataract surgery, intended to overmatch the paradigm of conventional phacoemulsification. Femtosecond laser-assisted cataract surgery (FLACS) enables a higher level of reproducibility, precision, accuracy, and customization when performing several steps of cataract (or lens) surgery. Capsulotomy, corneal incisions, lens fragmentation, and arcuate incisions are the main procedures performed using FLACS. As the demand for better refractive outcomes and spectacle independence increases, the features of FLACS are highly relevant, especially when considering the implantation of premium intraocular lenses, such as toric, enhanced depth-of-focus, or multifocal lenses. The present article reviews the state of the art of femtosecond laser-assisted cataract (lens) surgery, contemplating the advantages and limitations of the two types of femtosecond laser pulses available (high and low energy) by evaluating their reported outcomes and complications.

Refractive Predictability between Standard and Total Keratometry during the Femtosecond Laser-Assisted Cataract Surgery with Monofocal Intraocular Lens with Enhanced Intermediate Function

PURPOSE

We aimed to compare the accuracy of the intraocular lens (IOL) calculation formula using the standard keratometry (K) and total K (TK) during the femtosecond laser-assisted cataract surgery (FLACS) with a monofocal IOL with enhanced intermediate function using currently used formulas.

METHODS

A retrospective review of 125 eyes from 125 patients who had undergone FLACS with implantation of monofocal IOL with enhanced intermediate function was conducted. The predicted refractive power was calculated using an optical biometer (IOLmaster 700) according to the K and TK in the Barrett Universal II, SRK/T, Haigis, and Holladay 2 formulas. Absolute prediction error (APE) obtained from the actual postoperative refractive outcomes and the refractive error predicted in each formula was compared one month after surgery.

RESULTS

Mean APE ranged between 0.29 and 0.39 diopters (D) regardless of the calculation formula and the method of measuring corneal curvature. Significant differences were observed in the APE from the four formulas and the two keratometric measurements (p = 0.014). In a total of 125 eyes from 125 patients, the mean APE was lowest with the Barrett Universal II formula. Across all formulas, both the mean APE and the median APE tended to be lower for K than for TK, although there was no significant difference. Approximately 70% to 80% of the patients were included within 0.5 D of the refractive error across all formulas. The percentage of eyes within 0.5 D of APE outcomes was not statistically different between the K and TK data when using each formula.

CONCLUSIONS

Keratometric measurements considering the poster corneal curvature did not show any additional advantages when implanting the monofocal IOL with enhanced intermediate function during the FLACS.

Light adjustable intraocular lenses in cataract surgery: considerations

PURPOSE OF REVIEW

Light adjustable intraocular lens (LAL) is a promising concept in cataract surgery. This review explores considerations for the use of LALs.

RECENT FINDINGS

Through updates, the safety of LALs and light delivery devices have been enhanced, enabling more efficient treatment with lower ultraviolet (UV) energy. Preoperative topography and aberration are essential for understanding indications for LALs. Furthermore, when determining intraocular lens power, it is crucial to factor in potential postoperative myopia or hyperopic adjustments. This is achieved by establishing a proper postimplantation refractive target and considering potential wavefront changes. Postoperative adjustments for defocus and astigmatism have demonstrated excellent outcomes. Monovision strategy by adjustable blended vision of LALs revealed distance vision of 20/20 along with near vision of J2 in 96% of patients. However, the results of clinical studies on postrefractive cataract surgery showed contrasting outcomes at distance, indicating the need for further research results regarding its effectiveness. A new postoperative workflow needs to be designed to enable a systematic follow-up process.

SUMMARY

LALs are safe and demonstrate promising refractive outcomes. To achieve appropriate results, understanding the changes in optical characteristics associated with adjustment and constructing a new postoperative workflow are necessary.

Refractive cataract surgery

PURPOSE OF REVIEW

The aim of this study to provide an overview of recent publications and opinions in refractive cataract surgery.

RECENT FINDINGS

With the advent of intraocular lenses (IOLs) on different platforms, the surgeon has a wide arena of types of IOL to choose, depending on the patient's visual requirement. Optimization of the tear film, integrating tomography and topography devices for appropriate keratometry values, biometry, use of advanced formulas for IOL power calculation and application of newer IOLs can help achieve target refraction in cases scheduled for cataract surgery. Intraoperative aberrometry can be a useful aid for cataract surgery in postrefractive cases and can help minimize residual postoperative astigmatism.

SUMMARY

Evolvement and rapid advancement of technology allows to impart desired refractive outcomes in most of the cases postcataract surgery. Appropriate preoperative and intraoperative factors should be considered to achieve the desired postoperative outcome.

Immediately sequential bilateral cataract surgery

PURPOSE OF REVIEW

This review aims to clarify the advantages and disadvantages of immediately sequential bilateral cataract surgery (ISBCS) based on recent studies, illustrate the safety of this approach, the cost-effectiveness, and present the importance of inclusion protocols for the best results.

RECENT FINDINGS

In recent studies, the authors found no evidence of an increased risk of bilateral devastating complications such as endophthalmitis with ISBCS based on descriptive evidence compared to delayed sequential bilateral cataract surgery (DSBCS). Furthermore, recent studies on cost analyses showed that ISBCS resulted in fewer costs and significant cost savings to third-party payers, patients, and society compared to DSBCS.

SUMMARY

The ISBCS surgical approach decreases hospital visits, reduces costs, and provides rapid visual rehabilitation and neuro adaptation. The risk of bilateral simultaneous complications is now recognized to be very rare with intracameral antibiotics and compliance with correct protocols. With new generations of optical biometry and lens calculation formulas, refractive surprises are occasional for normal eyes. However, refractive surprise is controversial, especially in the implantation of presbyopia correction intra-ocular lenses, which must be evaluated carefully in the ISBCS approach.

Evaluating the Predictability of Postoperative Target Refraction Using the Prototype of a New Intraoperative Aberrometer

Despite all the progress in cataract and refractive lens surgery, refractive surprise is common in clinical practice. A significant postoperative refractive error is particularly annoying - and contributes to the patient's dissatisfaction with the procedure and the surgeon - when a multifocal IOL, an EDOF-IOL or a toric IOL has been implanted. The relatively new technology of intraoperative aberrometry offers the surgeon the option to intraoperatively measure the eye and its refraction, either directly after lens extraction and/or following IOL implantation. Currently, three different systems are available. In a number of studies, the technology has shown a better refractive predictability than preoperative biometry. Besides giving an evaluation of the prototype of a new intraoperative aberrometer, the I-O-W-A system, we also present our results on the influence of the kind of anaesthesia chosen and of two different IOL designs on the predictability of intraoperative aberrometry.

Refractive Predictability of a Swept Source Optical Coherence Tomography Biometer in Long and Short Eyes Implanted with Extended Depth of Focus Intraocular Lenses

Purpose

To determine the refractive predictability of Argos (Movu, a Santec company) measurements and the Barrett Universal II formula in long and short eyes implanted with an extended depth of focus (EDOF) intraocular lens (IOL).

Methods

This retrospective, non-interventional study included 86 eyes (55 long and 31 short) of 55 patients. Preoperative biometry was performed using the Argos. Preoperative IOL power formulas were the preprogrammed Barrett Universal II (BUII). Data were collected for refractive outcomes, postoperative prediction error (directional and absolute), and monocular corrected distance visual acuity (CDVA, Snellen).

Results

The mean absolute prediction error for BUII was 0.27 ± 0.26 D overall, 0.24 ± 0.20 D in long eyes, and 0.33 ± 0.33 D in short eyes. Overall, the percentage of eyes with ≤ 0.5 D prediction error was 84% for BUII. In long eyes, the percentage of eyes with ≤ 0.5 D prediction error was 90% for BUII. In short eyes, the percentage of eyes with ≤ 0.5 D prediction error was 74% for BUII. The percentage of eyes with ≤ 0.5 D of MRSE was 89% for long eyes and 94% for short eyes. Visual acuities were excellent in both long and short eyes, with > 90% of eyes 20/25 or better in each group.

Conclusion

The prediction error of Argos using BUII was low in long and short eyes at one month after EDOF IOL implantation.

Accuracy of new intraocular lens calculation formulas in Chinese eyes with short axial lengths

PURPOSE

To compare the measurement accuracy of new/updated intraocular lens (IOL) power calculation methods, namely, Kane, Emmetropia Verifying Optical (EVO), with existing methods (Barrett Universal II, Olsen, Haigis, Hoffer Q, Holladay 1, SRK/T) in Chinese eyes with axial lengths ≤ 22.5 mm.

METHODS

The study included data from patients who underwent uneventful cataract surgery with the insertion of ZCB00 IOL. Refractive prediction errors were determined by calculating the difference between postoperative refraction and the predicted refraction using each formula. Various parameters were evaluated, including mean prediction error (ME), mean absolute error (MAE), median absolute error (MedAE), and the percentage of eyes with prediction errors (PE) within different ranges.

RESULTS

The study enrolled 38 eyes of 38 patients, and the Barrett Universal II formula demonstrated the lowest MAE and MedAE among the tested formulas. Post hoc analysis using Wilcoxon signed-rank pairwise comparisons for non-parametric samples with Bonferroni correction revealed no significant difference in postoperative refractive prediction among all the formulas (P > 0.05). The percentage of eyes with PE within ± 0.5 D was as follows: Barrett Universal II, 81.58%; Haigis, 78.95%; EVO, 76.32%; Olsen, 76.32%; Holladay I, 73.68%; SRK/T, 71.05%; Kane, 68.42%; and Hoffer Q, 65.79%.

CONCLUSION

The Barrett Universal II formula was more accurate than the other formulas for Chinese eyes with AL ≤ 22.5 mm.

New Nitinol-based Thermomechanically Adjustable IOL Technology

PURPOSE

To evaluate the feasibility of new adjustable intraocular lens (IOL) technology.

METHODS

The foldable adjustable IOL consists of a nitinol mechanism placed in a haptic-optic cradle. Heating actuators on the nitinol mechanism with a continuous green laser achieve controlled movement of the mechanism and optic. Activation occurs in controlled steps: rotation in 1-degree steps over 360 degrees, and anterior posterior movement in 0.25-diopter (D) steps with a range of +1.50 D. The IOL was tested in vitro and in vivo in a rabbit eye. Foldability and unfolding were demonstrated through a 2.6-mm cartridge.

RESULTS

The adjustable lens mechanism was successfully tested in vitro and in vivo. Activation resulted in a change in optic position relative to the haptics and the capsular bag. Activation of the lever and ratchet mechanism showed radial advancement of the IOL clockwise and counterclockwise. In vivo rotatory movement was achieved after activation by the argon laser at 1 week after implantation. Anterior to posterior movement was accomplished by activating the circular spring actuator mechanism in the laboratory model. Uneventful folding and unfolding were performed.

CONCLUSIONS

A new adjustable IOL with a mechanism that responds in measured steps had been shown to move as planned after activation by argon laser. This was successful in the laboratory in both radial and anterior posterior movement. The radial movement was also proven in vivo in an animal model. Further refinement of the prototype is currently being undertaken. [J Refract Surg. 2023;39(10):662-667.].

Safety of office-based lens surgery: U.S. multicenter study

PURPOSE

To evaluate the rate of adverse events after office-based lens surgery performed across multiple private practices in the United States.

SETTING

36 private practices across the U.S.

DESIGN

Retrospective multicenter study.

METHODS

This analysis included case records of all consecutive patients who underwent office-based lens surgery for visually significant cataract, refractive lens exchange, or phakic intraocular lens implantation between August 2020 and May 2022 at 36 participating sites across the U.S. The study outcome measures included the assessment of intraoperative and postoperative complications such as the incidence of unplanned vitrectomy, iritis, corneal edema, and endophthalmitis after lens surgery. The frequency of patients requiring a return to the operating room (OR) or referral to a retina surgeon and the frequency of patients requiring hospitalization or calling emergency services (911) for any reason were also evaluated.

RESULTS

The study reviewed 18 005 cases of office-based cataract or refractive lens surgery performed at 36 clinical sites. The rates of postoperative endophthalmitis, toxic anterior segment syndrome, and corneal edema were 0.028%, 0.022%, and 0.027%, respectively. Unplanned anterior vitrectomy was performed in 0.177% of patients. Although 0.067% of patients needed to return to the OR, 0.011% of patients were referred to the hospital.

CONCLUSIONS

The rate of adverse events for office-based cataract or refractive lens surgery is similar to or less than the reported adverse event rate for modern cataract surgery in the ambulatory surgery center setting.

Randomized Trial Comparing Prediction Accuracy of Two Swept Source Optical Coherence Tomography Biometers

Purpose

To compare the prediction accuracy of the Argos biometer using standard keratometry to the prediction accuracy of the IOLMaster 700 biometer using Total Keratometry.

Methods

This was a randomized, prospective, single surgeon study of 80 right eyes of 80 patients that had preoperative biometry with both the Argos and IOLMaster 700 devices, followed by cataract surgery and intraocular lens (IOL) implantation. Prediction errors (directional and absolute) for each device were determined from the 1 month postoperative manifest refraction.

Results

The directional prediction error was 0.07 ± 0.32 D for the Argos and 0.08 ± 0.34 D for the IOLMaster 700. The mean of the difference in prediction error (directional) was 0.02 D, which was not statistically significant (p > 0.05). The absolute prediction error was 0.21 ± 0.25 D for the Argos and 0.25 ± 0.24 D for the IOLMaster 700. The mean of the difference in absolute prediction error was 0.04 D, which was statistically significant (p < 0.004) but not clinically significant. The percentage of eyes with absolute prediction error ≤ 0.5 D was 91% (73 eyes) for the Argos and 88% (70 eyes) for the IOLMaster 700. This difference was not statistically significant.

Conclusion

The prediction accuracies were similar between the Argos and IOLMaster 700 in eyes with normal axial length. There was a significant difference in mean absolute prediction error between devices; however, this was not clinically meaningful.

Accuracy of refractive outcomes using standard or total keratometry for intraocular lens power formulas in conventional cataract surgery

PURPOSE

To evaluate if total keratometry (TK) is better than standard keratometry (K) for predicting an accurate intraocular lens (IOL) refractive outcome in virgin eyes using four IOL power calculation formulas.

METHODS

447 eyes that underwent monofocal intraocular lens implantation were enrolled in this study. IOLMaster 700 (Carl Zeiss Meditech, Jena, Germany) was used for optical biometry. Prediction error (PE), mean absolute prediction error (MAE), median absolute prediction error (MedAE), proportions of eyes within ± 0.25 diopters (D), ± 0.50 D, ± 0.75 D, ± 1.00 D, ± 2.00 D prediction error, and formula performance index (FPI) were calculated for each K- and TK-based formula.

RESULTS

Overall, the accuracy of each TK and K formula was comparable. The MAEs and MedAEs showed no difference between most of the K-based and the TK-based formula; only the MAE of TK was significantly higher than that of K using the Haigis. The percent of eyes within ± 0.25 D PE for TK was not significantly different from that for K. The analysis of PE across various optical dimensions revealed that TK had no effect on the refractive results in eyes with different preoperative axial length, anterior chamber depth, keratometry, and lens thickness. The K-based Barrett Universal II formula performed excellently, showed the leading FPI score, and had the best refractive prediction outcomes among the four formulas.

CONCLUSION

TK and K can be used for IOL power calculation in monofocal IOL implantation cataract surgery in virgin eyes, as both are comparable. In all investigated formulas, the predictive accuracy of TK-based formulas is not superior to that of standard K-based formulas.

Prospective Randomized Single-Masked Study of Bilateral Isofocal Optic-Design or Monofocal Intraocular Lenses

PURPOSE

To assess refractive and visual outcomes of bilateral implantation of an isofocal optic-design intraocular lens (IOL) or a monofocal IOL following cataract surgery.

METHODS

A total of 127 patients were recruited into a prospective, single-masked, randomized trial. Sixty-five patients bilaterally implanted with the Isopure Isofocal IOL and 62 patients with the Micropure Monofocal IOL were followed for 4-6 months. Refraction, monocular and binocular uncorrected-distance-visual acuity, corrected-distance-visual acuity (CDVA), uncorrected-intermediate-visual acuity and distance-corrected-intermediate-visual acuity (DCIVA, 66/80 cm), uncorrected-near-visual acuity, and distance-corrected-near-visual acuity (DCNVA, 40 cm) were evaluated. Binocular defocus curve, binocular contrast sensitivity (photopic, mesopic with/without glare), and glare and halo phenomena were also measured.

RESULTS

99.23% of eyes were within ±1.00D and 84.62% of eyes within ±0.50D for the Isopure patients and 98.39% and 82.26% for the Micropure patients, respectively. The mean spherical-equivalent was -0.06 ± 0.36D and 0.10 ± 0.32D for the Isopure and Micropure patients, respectively. 98.5% and 100% of patients implanted with the Isopure and Micropure IOLs showed a cumulative binocular CDVA value ≥20/20, respectively. 80% and 67.70% of patients implanted with the Isopure presented a binocular DCIVA ≥20/25 at 80 and 66 cm, respectively. These percentages were 46.8% and 40.3% with the Micropure IOL, respectively. For Isopure, 7.7%, 30.8%, and 58.5% of patients presented a DCNVA ≥20/25, ≥20/32 and ≥20/40, respectively. These values were lower for the Micropure: 1.6%, 19.4% and 46.8%, respectively. Defocus curves showed similar good visual acuity at distance for both lenses with better intermediate vision for the Isopure. Both groups presented good contrast sensitivity, and the size and intensity of halo and glare phenomena were similar between the two. No adverse-events were reported.

CONCLUSION

Our trial shows that both IOLs provide excellent visual acuity and contrast sensitivity for far vision with similar photic phenomena, and the Isopure IOL improved unaided intermediate vision performance.

Influence and predictive value of optional parameters in new-generation intraocular lens formulas

PURPOSE

To evaluate the accuracy of various variations of new-generation multivariate intraocular lens (IOL) power calculation using the Barrett Universal II, Castrop, Emmetropia Verifying Optical 2.0, Hill-Radial Basis Function 3.0, Kane, and PEARL-DGS formulas with and without optional biometric parameters.

SETTING

Tertiary care academic medical center.

DESIGN

Retrospective case series. Single-center study.

METHODS

Inclusion of patients after uneventful cataract surgery implanting AU00T0 IOLs. Data from one eye per patient were randomly included. Eyes with a corrected distance visual acuity worse than 0.1 logMAR were excluded. IOLCON-optimized constants were used for all formulas other than the Castrop formula. The outcome measures were prediction error (PE) and absolute prediction error (absPE) for the 6 study formulas.

RESULTS

251 eyes from 251 patients were assessed. Excluding lens thickness led to statistically significant differences in absPE in several formulas. Leaving out horizontal corneal diameter did not impact absPE in several formulas. Differences in PE offset were observed between the various formula variations.

CONCLUSIONS

When using multivariate formulas with an A-constant, including certain optional parameters is vital for optimal refractive results. Formula variations excluding certain biometric parameters need specifically optimized constants and do not perform similarly when using the constant of the respective formula using all parameters.

Comparing Predictive Accuracy of a Swept Source Optical Coherence Tomography Biometer and an Optical Low Coherence Reflectometry Biometer

Purpose

To compare the refractive accuracy resulting from calculations based on measurements with a swept-source optical coherence tomography (SS-OCT) biometer compared to calculations based on measurements with an optical low coherence reflectometry (OLCR) biometer at one month postoperatively.

Methods

This was a retrospective comparative non-interventional study of preoperative biometry and postoperative refraction and visual acuity of 200 eyes. All eyes had preoperative biometry with both the Argos (Movu, a Santec company) and Lenstar LS900 (Haag-Streit AG) devices. Data were collected for mean postoperative prediction error (directional and absolute), preoperative mean K, delta K (corneal astigmatism), axial length, and anterior chamber depth.

Results

The mean directional prediction error was -0.15 ± 0.47 D for Argos and -0.31 ± 0.50 D for Lenstar LS900, and there was a statistically significant mean of the differences (0.16 ± 0.24 D; p < 0.001). The mean absolute prediction error was 0.35 ± 0.34 D for Argos and 0.42 ± 0.41 D for Lenstar LS900, and there was a statistically significant mean of the differences (-0.07 ± 0.24 D; p < 0.001). Neither the differences in directional prediction error nor the differences in absolute prediction error were clinically significant.

Conclusion

The directional and absolute prediction accuracies were statistically significant, but not clinically different between the Argos and Lenstar LS900 devices. In addition, differences between preoperative K, AL, and ACD measurements were not clinically significant.

Safety, effectiveness, and cost-effectiveness of immediate versus delayed sequential bilateral cataract surgery in the Netherlands (BICAT-NL study): a multicentre, non-inferiority, randomised controlled trial

BACKGROUND

In an ageing population, efficiency improvements are required to assure future accessibility of cataract care. We aim to address remaining knowledge gaps by evaluating the safety, effectiveness, and cost-effectiveness of immediate sequential bilateral cataract surgery (ISBCS) versus delayed sequential bilateral cataract surgery (DSBCS). We hypothesised that ISBCS is non-inferior to DSBCS, regarding safety and effectiveness, and being superior in cost-effectiveness.

METHODS

We did a multicentre, non-inferiority, randomised controlled trial, which included participants from ten Dutch hospitals. Eligible participants were 18 years or older, underwent expected uncomplicated surgery, and had no increased risk of endophthalmitis or refractive surprise. Participants were randomly assigned (1:1) to either the ISBCS (intervention) group or DSBCS (conventional procedure) group, using a web-based system stratified by centre and axial length. Participants and outcome assessors were not masked to the treatment groups because of the nature of the intervention. The primary outcome was the proportion of second eyes with a target refractive outcome of 1·0 dioptre (D) or less 4 weeks postoperatively, with a non-inferiority margin of -5% for ISBCS versus DSBCS. For the trial-based economic evaluation, the primary endpoint was the incremental societal costs per quality-adjusted life-year. All analyses were done by a modified intention-to-treat principle. Costs were calculated by multiplying volumes of resource use with unit cost prices and converted to 2020 Euros (€) and US$. This study was registered with ClinicalTrials.gov, number NCT03400124, and is now closed for recruitment.

FINDINGS

Between Sept 4, 2018, and July 10, 2020, a total of 865 patients were randomly assigned to either the ISBCS group (427 [49%] patients; 854 eyes) or DSBCS group (438 [51%] patients; 876 eyes). In the modified intention-to-treat analysis, the proportion of second eyes with a target refraction of 1·0 D or less was 97% (404 of 417 patients) in the ISBCS group versus 98% (407 of 417) in the DSBCS group. The percentage difference was -1% (90% CI -3 to 1; p=0·526), thereby establishing non-inferiority for ISBCS compared with DSBCS. Endophthalmitis was not observed or reported in either group. Adverse events were comparable between groups, with only a significant difference in disturbing anisometropia (p=0·0001). Societal costs were €403 (US$507) lower with ISBCS than with DSBCS. The cost-effectiveness probability of ISBCS versus DSBCS was 100% across the willingness-to-pay range of €2500-80 000 (US$3145-100 629) per quality-adjusted life-year.

INTERPRETATION

Our results showed non-inferiority of ISBCS versus DSBCS regarding effectiveness outcomes, comparable safety, and superior cost-effectiveness of ISBCS. National cost savings could amount to €27·4 million (US$34·5 million) annually, advocating for ISBCS if strict inclusion criteria are applied.

FUNDING

Research grant from The Netherlands Organization for Health Research and Development (ZonMw) and Dutch Ophthalmological Society.

Managing low corneal astigmatism in patients with presbyopia correcting intraocular lenses: a narrative review

Cataract surgery has become a refractive procedure in which emmetropia is the goal, with the implantation of extended depth-of-focus or multifocal intraocular lenses (IOLs) being the commonly selected option to restore vision beyond the far distance. The selection criteria for implanting these lenses can differ from those for monofocal IOLs and even between technologies, as eye characteristics can affect postoperative visual performance. Corneal astigmatism is an eye characteristic that can affect visual performance differently, depending on the implanted IOL. The magnitude of corneal astigmatism, the tolerance of the IOL to this astigmatism, economic aspects, comorbidities, and the efficacy of astigmatism treatment are factors that can make surgeons' doubt as to what astigmatism treatment should be applied to each patient. This review aims to summarize the current evidence related to low astigmatism tolerance in presbyopia-correcting lenses, the efficacy achieved through corneal incisions, and their comparison with the implantation of toric IOLs.

Dry Eye Disease as a Cause of Refractive Errors After Cataract Surgery - A Systematic Review

Dry eye disease (DED) is a multifactorial ocular surface disorder characterized by loss of tear film homeostasis with associated ocular symptoms, like dryness, foreign body sensation, and inflammation. Numerous reports confirm an increase in dry eye symptoms after cataract surgery. DED also significantly disturbs preoperative biometric measurements, mainly by changes in keratometry measurements. The purpose of this study is to evaluate the effect of DED on biometric measurements before cataract surgery and postoperative refractive errors. PubMed database was searched for keywords: cataract surgery, dry eye disease, refractive error, refractive outcomes, keratometry, and biometry. Four clinical studies evaluating the effect of DED on refractive errors were included. In all studies, biometry was performed before and after dry eye treatment, and the mean absolute error was compared. Various substances have been used to treat dry eye, such as cyclosporin A, liftitegrast, and loteprednol. The refractive error was significantly lower after treatment in all studies. The results unanimously indicate that refractive errors can be reduced by proper treatment of DED before cataract surgery.

Femtosecond Laser Capsulotomy in Previous Radial Keratotomy

PURPOSE

The aim of this study was to describe clinical experience using femtosecond laser-assisted anterior capsulotomy in eyes with previous radial keratotomy.

METHODS

Eyes of patients with previous radial keratotomy and cataract-related vision impairment who underwent phacoemulsification and intraocular lens implantation were retrospectively reviewed. Eyes with any vision impairment cause other than cataract or previous radial keratotomy were excluded.

RESULTS

Sixteen postradial keratotomy eyes were included. In 5 patients, manual anterior capsulectomy was successfully performed. Six eyes underwent femtosecond laser capsulotomy using routine parameters (incision depth 500 μm and 4 μJ power), of which in 3 eyes capsulotomies were complete, whereas in the other 3 eyes incomplete capsulotomy was evident. In 3 patients, both incision depth and power parameters were doubled (incision depth 1000 μm and 8 μJ power), whereas in 2 patients, only the pulse energy was doubled (8 μJ power) and in all 6 cases, the capsulotomy was successfully completed. At the last follow-up, all capsulotomies were intact without radial tears, and the intraocular lenses were stable and central.

CONCLUSIONS

Radial corneal scars after previous radial keratotomy may interfere with femtosecond laser-assisted anterior capsulotomy using routine parameters. Surgeons should be alert and ready to convert to manual anterior capsulectomy. Modification of the laser parameters may overcome this potential complication.

Comparing Visual Outcomes of Light Adjustable Intraocular Lenses in Patients With and Without Prior History of Corneal Refractive Surgery

PURPOSE

To assess visual outcomes of light adjustable intraocular lens (LAL; Calhoun Vision, Inc) implantation after cataract extraction in patients with a history of corneal refractive surgery.

METHODS

The records of patients who received LALs with and without a history of corneal refractive surgery were retrospectively reviewed. Data for 51 eyes (30 patients) with a history of corneal refractive surgery and 52 eyes (44 patients) without refractive surgery were analyzed. A total of 36 eyes of patients with and 43 eyes of patients without a history of corneal refractive surgery had 12-month follow-up data available. The primary outcomes evaluated were uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA).

RESULTS

At 12 months, 31% of eyes with a history of corneal refractive surgery had a UDVA of 20/20 or better and 97% of eyes were 20/40 or better. In contrast, 63% of patients with no history of corneal refractive surgery had 20/20 UDVA or better at 12 months and 100% were 20/40 or better. Of patients with a history of corneal refractive surgery, 55% and 83% of eyes at 12 months were within ±0.50 and ±1.00 diopters, respectively, of the target refraction compared to 89% and 96% of eyes without a history of corneal refractive surgery.

CONCLUSIONS

LALs are a promising platform for achieving excellent visual outcomes following cataract surgery. Patients with a prior history of corneal refractive surgery can achieve excellent visual outcomes with the LAL. However, this study found that patients with a history of corneal refractive surgery demonstrated less predictable visual acuity outcomes when compared to patients without a history of corneal refractive surgery. [J Refract Surg. 2023;39(5):311-318.].

Accuracy of Intraocular Lens Power Calculation Based on Total Keratometry in Patients With Flat and Steep Corneas

PURPOSE

To analyze the accuracy of the current intraocular lens power calculation formulas using standard keratometry (K) and total keratometry (TK) data in patients with flat and steep corneas.

DESIGN

Retrospective consecutive cross-sectional study.

METHODS

An optical biometer with swept-source optical coherence tomography was used in this retrospective study. The standard deviation (SD), mean absolute error (MAE), median absolute error (MedAE), and the proportion of eyes with prediction error (PE) within ±0.25 diopter (D), ±0.5 D, ±0.75 D, and ±1.00 D were calculated to evaluate the refractive outcomes of each formula.

RESULTS

A total of 231 eyes from 231 patients were included. In the entire study cohort, the Emmetropia Verifying Optical (EVO) formula using TK data showed the lowest SD (0.383) and MAE (0.30) and the highest percentage of cases with a PE within ±0.5 D (81.4%). In the flat keratometry group, the EVO (P = .042), Haigis (P = .043), Hoffer Q (P = .038) and Holladay 1 (P = .013) formulas using TK data had significantly lower SD than using K data. The EVO formula using TK data showed the lowest SD (0.357) and MAE (0.28). In the steep keratometry group, the Hoffer Q (P = .036) and SRK/T (P = .029) formulas using TK data had significantly lower SD than using K data. The BUII TK formula showed the lowest SD (0.431), MedAE (0.26), and MAE (0.32).

CONCLUSION

The TK data set showed a better trend of refractive outcomes, especially in the flat and steep keratometry groups. EVO (TK) and BUII TK formulas were suggested for eyes with K values lower than 42 D and K values higher than 46 D, respectively.

Visual Performance at Different Distances After Implantation of an Isofocal Optic Design Intraocular Lens

PURPOSE

To evaluate refractive and visual outcomes at different distances after implantation of an isofocal optic design intraocular lens (IOL) following cataract surgery.

METHODS

This multicentric, retrospective/prospective, open-label, observational study considered 183 eyes of 109 patients who were implanted with the ISOPURE 123 (PhysIOL) IOL. The main outcome measures were refractive error and monocular and binocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), and distance-corrected intermediate visual acuity (DCIVA) at 66 and 80 cm, uncorrected near visual acuity (UNVA), and distance-corrected near visual acuity (DCNVA) at 40 cm. Binocular visual acuity at different vergences (defocus curve) was also measured. Patients were evaluated at least 120 days postoperatively.

RESULTS

A total of 95.7% of the eyes were within ±1.00 diopter (D) and 73.2% of the eyes were within ±0.50 D; the mean postoperative spherical equivalent was -0.12 ± 0.42 D. There were 90.54% and 98.57% of patients presenting a cumulative binocular UDVA and CDVA value of 20/25 or better, respectively; 80.65% and 50.0% of patients presented a binocular DCIVA value of 20/25 or better at 80 and 66 cm, respectively; and 41.94% of patients presented a binocular DCNVA value of 20/40 or better. The through-focus curve showed good visual acuity at far and intermediate distances with a depth of focus value of 1.50 D. No adverse events were reported.

CONCLUSIONS

The current study shows that this isofocal optic design IOL provides excellent visual performance for far vision and functional intermediate vision with an extended range of vision. This lens is an effective option for providing functional intermediate vision and correcting aphakia. [J Refract Surg. 2023;39(3):150-157.].

Cataracts

94 million people are blind or visually impaired globally, and cataract is the most common cause of blindness worldwide. However, most cases of blindness are avoidable. Cataract is associated with decreased quality of life and reduced life expectancy. Most cases of cataract occur after birth and share ageing and oxidative stress as primary causes, although several non-modifiable and modifiable risk factors can accelerate cataract formation. In most patients, phacoemulsification with intraocular lens implantation is the preferred treatment and is highly cost-effective. There has been an increase in the use of comprehensive cataract surgical services, including diagnoses, treatment referrals, and rehabilitation. However, global inequity in surgical service quality is still a limitation. Implementation of preoperative risk assessment, risk reduction strategies, and new surgical technologies have made cataract surgery possible at an earlier stage of cataract severity with the expectation of good refractive outcomes. The main challenge is making the service that is currently available to some patients accessible to all by use of universal health coverage.

High prevalence of refractive errors in an elderly population; a public health issue

PURPOSE

To determine the prevalence of myopia and hyperopia and their associated demographic and ocular factors in people 60 years of age and above.

METHODS

The sampling was performed using a multi-stage stratified random cluster sampling method. The complete demographic and case history information were collected through an interview. Then, all participants underwent optometric examinations including measurement of uncorrected and best-corrected visual acuity, objective, and subjective refraction. Myopia and hyperopia were defined as a spherical equivalent (SE) refraction worse than -0.50 diopters (D) and + 0.50 D, respectively.

RESULTS

Three thousand three hundred ten of 3791 invitees participated, and the data of 3263 individuals were analyzed for this report. The mean age of participants was 68.25 ± 6.53 (60 to 97) years, and 1895 (58.1%) of them were female (number of male/female participants = 1368/1895). The prevalence of myopia and hyperopia was 31.65% (95% CI: 29.68 -33.61) and 45.36% (95% CI: 43.36 -47.37), respectively. The prevalence of severe myopia and hyperopia was 1.14% (95% CI: 0.73 -1.55) and 2.27% (95% CI: 1.57 -2.97), respectively. Based on the results of multiple logistic regression, the prevalence of myopia had a statistically significant direct relationship with age (OR: 1.04; p < 0.001), history of glaucoma surgery (OR:2.75; p < 0.001), pseudophakia (OR: 2.27; p < 0.001), axial length (OR:3.05; p < 0.001), and mean keratometry (OR:1.61; p < 0.001). The education level was significantly inversely related to the myopia prevalence. Moreover, a history of glaucoma surgery (OR:0.44; p < 0.001), pseudophakia (OR = 0.15; p < 0.001), axial length (OR:35; p < 0.001) and mean keratometry (OR:0.62; p < 0.001) were significantly inversely related to the prevalence of hyperopia. 19% and 40.02% of myopic and hyperopic patients had complete visual acuity after correction of refractive error, respectively.

CONCLUSION

The prevalence of refractive errors was high in the Iranian elderly population. A large percentage of the elderly still did not have complete visual acuity after the correction of refractive errors indicating the necessity for attention to other ocular diseases in this age group. The history of cataract and glaucoma surgery could be associated with a myopic shift of refractive error.

Factors contributing to long-term refractive error after cataract surgery

PURPOSE

To evaluate factors that may influence the direction and extent of long-term refractive error after cataract surgery.

METHODS

This was a retrospective observational study conducted across two private practices in Sydney, NSW, Australia. The study population consisted of patients who underwent cataract phacoemulsification surgery between January 1 and December 31, 2018. Patients who received cataract surgery combined with another procedure were excluded. Demographic and biometric data including anterior chamber depth (ACD), keratometry, central corneal thickness, axial length (AL) and lens thickness were obtained pre-operatively. Spherical equivalent (SEQ) refraction was measured at 2 months and 3 years after surgery and compared with target refraction. Factors associated with refractive error were analyzed.

RESULTS

This study included 221 eyes of 122 patients. A refractive error within 1.00 D was achieved in 217 eyes (98.2%) at 3 years post-operatively. Mean prediction error decreased significantly between 2 months and 3 years after surgery irrespective of whether eyes were more myopic (p < 0.001) or more hypermetropic than predicted (p < .0001). Pre-operative ACD and ACD-to-AL ratio were significantly associated with SEQ prediction error.

CONCLUSION

After cataract surgery, refractive outcomes may be influenced by ACD and ACD-to-AL ratio. The pre-operative assessment of these risk factors may better inform IOL selection in individual patients. Prospective studies in a larger cohort are required.

An update on immediate sequential bilateral cataract surgery

PURPOSE OF REVIEW

The aim of this study was to present an overview of recent publications and opinions in the field of same-day bilateral cataract surgery.

RECENT FINDINGS

A Cochrane review was published comparing immediate sequential bilateral cataract surgery (ISBCS) and delayed sequential bilateral cataract surgery (DSBCS) with regard to safety outcomes, costs and cost-effectiveness. In addition, several large database studies provided more information on incidences of rare complications such as unilateral and bilateral endophthalmitis rates.

SUMMARY

Recently available evidence showed that ISBCS is an effective and cost-effective alternative to DSBCS. Nonetheless, additional (randomized) registry studies, randomized controlled trials and cost-effectiveness studies are needed to evaluate bilateral endophthalmitis rates, refractive outcomes and cost-effectiveness of ISBCS compared with DSBCS.

Comparative visual outcomes of EDOF intraocular lens with FLACS vs conventional phacoemulsification

PURPOSE

To investigate the visual quality after femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification surgery (CPS) with the implantation of an extended depth-of-focus (EDOF) intraocular lens (IOL) TECNIS Symfony.

SETTING

Eye Center, the Second Affiliated Hospital of Zhejiang University, Zhejiang, China.

DESIGN

Prospective cohort study.

METHODS

Patients were given the option to choose FLACS or CPS and were implanted with a TECNIS Symfony. Main outcome measures were postoperative examinations that included defocus curves, contrast sensitivity (CS), optic path difference aberrometry scan, anterior segment photography, and questionnaires.

RESULTS

261 patients (261 eyes) were enrolled. The circularity index of FLACS was more precise than that of CPS ( P = .001). FLACS demonstrated a significantly lower IOL decentration ( P = .011) and IOL tilt ( P = .009). FLACS presented a significantly lower total aberration ( P < .001), higher-order aberrations (HOAs) ( P = .001), coma ( P = .001), and spherical aberration ( P < .001). With IOL decentration of more than 0.40 mm, total internal aberration ( P = .023) and HOAs ( P = .045) were significantly deteriorated. As for defocus curve, FLACS was better at -1.00 diopter ( P < .01). The FLACS group achieved higher CS at 6 to 18 cycles per degree under glare condition ( P < .05). With regard to photic phenomena, the FLACS group received better outcomes ( P < .05).

CONCLUSIONS

With the implantation of an EDOF IOL, FLACS could precisely control the shape and size of the capsulotomy and induce a significantly better-centered IOL, leading to higher visual performance compared with CPS.

Advances in artificial intelligence models and algorithms in the field of optometry

The rapid development of computer science over the past few decades has led to unprecedented progress in the field of artificial intelligence (AI). Its wide application in ophthalmology, especially image processing and data analysis, is particularly extensive and its performance excellent. In recent years, AI has been increasingly applied in optometry with remarkable results. This review is a summary of the application progress of different AI models and algorithms used in optometry (for problems such as myopia, strabismus, amblyopia, keratoconus, and intraocular lens) and includes a discussion of the limitations and challenges associated with its application in this field.

Femtosecond laser-assisted cataract surgery: Update and perspectives

Cataract surgery is among the most frequently performed surgical procedures worldwide and has a tremendous impact on patients' quality of life. Phacoemulsification (PCS) is accepted as a standard of care; its technique has continuously evolved and already achieved good anatomical, visual, and refractive outcomes. Lasers in ophthalmology are widely used in clinical practice, femtosecond lasers (FSLs) for corneal surgery in particular. It was natural to assess the usefulness of FSL in cataract surgery as this technology was within reach. Indeed, precise and reproducible cuttings provided by FSL platforms could improve standardization of care and limit the risk associated with the human element in surgery and provide a step toward robot-assisted surgery. After docking and planning the procedure, femtosecond lasers are used to perform corneal incisions, capsulorhexis, lens fragmentation, and arcuate incisions in an automated manner. A well-constructed corneal incision is primordial as it offers safety during the procedure, self-seals afterward, and influences the refractive outcome. Capsulorhexis size, centration, and resistance to shearing influence the surgery, intraocular lens (IOL) centration and stability, and posterior capsular opacification formation. Lens fragmentation is where most of the energy is delivered into the eye, and its amount influences endothelial cell damage and potential damage to other ocular structures. The arcuate incisions offer an additional opportunity to influence postoperative astigmatism. Femtosecond laser-assisted cataract surgery (FLACS) has been a topic of research in many studies and clinical trials that attempted to assess its potential benefits and cost-effectiveness over PCS and is the subject of this mini-review.

Comparisons of outcomes and complications of immediate sequential bilateral cataract surgery and unilateral cataract surgery in a tertiary hospital in South Korea

We investigated the proportions of immediate sequential bilateral cataract surgery (ISBCS) and unilateral cataract surgery during the coronavirus disease 2019 pandemic and compared visual outcomes between the two groups in a tertiary hospital in South Korea. We reviewed 441 cataract surgeries performed between March 1, 2021, and October 31, 2021, at Korea University Guro Hospital by a single surgeon (J.S.S). Medical records of demographics, preoperative visual acuity, corneal astigmatism, axial length, preoperative spherical equivalent, preoperative target (using Barrett's Universal 2 formula), postoperative visual acuity, postoperative refractive error, and postoperative complications were evaluated. Among all patients, 322 (73.0%) eyes underwent ISBCS, and 119 (27.0%) eyes underwent unilateral cataract surgery. The preoperative corrective distance visual acuity (CDVA) was lower in the unilateral cataract surgery group (0.40 ± 0.45 logMAR) than the ISBCS group (0.28 ± 0.16 logMAR, P = 0.008), whereas there was no significant difference in postoperative CDVA between the two groups (0.06 ± 0.10 logMAR vs. 0.07 ± 0.16 logMAR, P = 0.63). There was also no difference in the absolute refractive error between the two groups (0.46 ± 0.37 diopters [D] vs. 0.42 ± 0.38 D, P = 0.63). The preoperative CDVA (P = 0.000) was the significant factor influencing absolute refractive error (r = 0.191, P < 0.001). There was no difference in complications between the two groups, although two patients in the ISBCS group complained of postoperative strabismus.

Unexpected Poor Vision within 24 h of Uneventful Phacoemulsification Surgery-A Review

Review on day one post uneventful phacoemulsification surgery is no longer standard practice due to the infrequency of complications when using modern cataract removal techniques. Clinicians are therefore likely to be unfamiliar with the potential causes of reduced vision when presented with a patient in the immediate postoperative period. The purpose of this review is to discuss the various differential causes of early visual loss, for the benefit of clinicians presented with similar patients in emergency care, with the use of an illustrative clinical case of paracentral acute middle maculopathy (PAMM), which recently presented to the authors. A thorough literature search on Google Scholar was conducted, and only causes of visual loss that would manifest within 24 h postoperatively were included. Complications are inherently rare in this period; however, various optical, anterior segment, lens-related and posterior segment causes have been identified and discussed. Front-line clinicians should be aware of these differentials with different mechanisms. PAMM remains to be the only cause of unexpected visual loss within this time frame that may have no abnormal findings on clinical examination.