Prospective Intrapatient Comparison of 6.0-Millimeter Optic Single-Piece and 3-Piece Hydrophobic Acrylic Foldable Intraocular Lenses

Factors affecting the refractive error after cataract surgery

Modern cataract surgery has entered the era of precision refractive surgery and is no longer only about the restoration of vision, and the factors affecting the refractive error after cataract surgery are gaining increasing attention with the patients' growing expectation of postoperative visual quality. The refractive error after cataract surgery is related to the accurate measurement of ocular biological parameters, the optimization of the intraocular lens calculation formula, and the prediction of the effective lens position. Clinicians must consider multiple factors to reduce the postoperative refractive error and improve the postoperative satisfaction of cataract patients. In this work, we review factors that affect the refractive error after cataract surgery.

How to choose the intraocular lens power calculation formulas in eyes with extremely long axial length? A systematic review and meta-analysis

OBJECTIVE

To evaluate the accuracy of 10 formulas for calculating intraocular lens (IOL) power in cataract eye with an axial length (AL) of more than 28.0 mm.

METHODS

We searched scientific databases including PubMed, EMBASE, Web of Science and Cochrane Library for research published over the past 5 years, up to Sept 2023. The inclusion criteria were case series studies that compared different formulas (Barrett II, EVO, Kane, Hill-RBF, Haigis, Hoffer Q, Holladay 1, SRK/T, Holladay 1 w-k and SRK/T w-k), in patients with extremely long AL undergoing uncomplicated cataract surgery with IOL implantation. The mean difference (MD) of mean absolute error (MAE) and the odds ratio (OR) of both the percentage of eyes within ±0.50D of prediction error (PPE±0.50D) and the percentage of eyes within ±1.00D of prediction error (PPE±1.00D) among different formulas were pooled using meta-analysis.

RESULTS

A total of 11 studies, involving 1376 eyes, were included to evaluate the 10 formulas mentioned above. Among these formulas, Barrett II, EVO, Kane, and Hill-RBF demonstrated significantly lower MAE values compared to SRK/T. Furthermore, Kane and Hill-RBF had lower MAE values than EVO. Additionally, Barrett II and Kane yielded significantly lower MAE values than Haigis while Hill-RBF showed significantly lower MAE values than Holladay 1. Moreover, Hill-RBF showed the highest values for both PPE±0.50D and PPE±1.00D, followed by Kane. Both EVO and Kane had higher values of PPE±0.50D and PPE±1.00D compared to Haigis and SRK/T.

CONCLUSION

The Wang-Koch adjusted formulas and new-generation formulas have shown potential for higher accuracy in predicting IOL power for cataract patients with extremely long AL compared to traditional formulas. Based on the current limited clinical studies, Hill-RBF and Kane formulas seem to be a better choice for eyes with extremely long AL.

Implantation of a capsular tension ring during cataract surgery attenuates predicted remodeling of the post-surgical lens capsule along the visual axis

Introduction: Cataract surgery permanently alters the mechanical environment of the lens capsule by placing a hole in the anterior portion and implanting an intraocular lens (IOL) that has a very different geometry from the native lens. We hypothesized that implant configuration and mechanical interactions with the post-surgical lens capsule play a key role in determining long-term fibrotic remodeling. Methods: We developed the first finite element-growth and remodeling (FE-G&R) model of the post-surgical lens capsule to evaluate how implantation of an IOL with and without a capsular tension ring (CTR) impacted evolving lens capsule mechanics and associated fibrosis over time after cataract surgery. Results: Our models predicted that implantation of a CTR with the IOL into the post-surgical lens capsule reduced the mechanical perturbation, thickening, and stiffening along the visual axis in both the remnant anterior and posterior portions compared to implantation of the IOL alone. Discussion: These findings align with patient studies and suggest that implantation of a CTR with the IOL during routine cataract surgery would attenuate the incidence of visually-debilitating capsule fibrosis. Our work demonstrates that use of such modeling techniques has substantial potential to aid in the design of better surgical strategies and implants.

Influence of the CleaRing intraocular open capsule device on refractive predictability in cataract surgery

BACKGROUND

The marked improvement in cataract surgery and intraocular lens (IOL) quality has led to a decline in posterior capsular opacification (PCO) incidence; however, PCO remains a common complication of cataract surgery. The CleaRing intraocular capsule open device (IOCD) decreases PCO incidence. We aimed to investigate the influence of the CleaRing IOCD on refractive predictability in cataract surgery.

METHODS

We conducted this prospective pilot study at the Wolfson Medical Center, Holon, Israel. Ten eyes of patients who underwent cataract surgery and insertion of an IOL after IOCD implantation into the capsular bag were included. All patients completed 12 months of follow-up, including refraction, measurement of uncorrected (UDVA) and best-corrected distance visual acuity (CDVA), slit-lamp biomicroscopy, and ultrasound biomicroscopy.

RESULTS

All the surgeries were uneventful, with no postoperative complications. The IOL was centred in the device and bag in all cases. The mean prediction error at 1 and 12 months postoperatively was +0.28 ± 0.32 D and +0.50 ± 0.32 D, respectively. The mean UDVA was 0.17 ± 0.13 and 0.15 ± 0.11 logMAR, and the mean CDVA was 0.04 ± 0.10 and 0.04 ± 0.06 logMAR, respectively. The manifest refractive cylinders at 12 months postoperatively were compatible with corneal astigmatism.

CONCLUSIONS

Implantation of the IOCD resulted in a slight, predicted, and stable hyperopic shift with a low standard deviation. The standard deviation of the prediction error demonstrated excellent refractive accuracy and predictability using the IOCD, which was as low as 0.32 D at the 12-month follow-up.

Long-term Clinical Outcomes After Trifocal Intraocular Lens Implantation: A Retrospective Observational Study

PURPOSE

To evaluate the long-term stability of the AcrySof IQ PanOptix TFNT00 intraocular lens (IOL) (Alcon Laboratories, Inc).

METHODS

This was a retrospective review of 1,065 eyes (745 patients) who underwent implantation of a PanOptix IOL. A total of 296 eyes (mean age: 58.62 ± 5.63 years and preoperative refractive error: -0.68 ± 3.01 diopters [D]) met inclusion criteria for this study. The objective refraction, uncorrected distance and near visual acuity (UDVA and UNVA), and corrected distance visual acuity (CDVA) were evaluated at postoperative months 1, 2, 6, 12, 24, and 36.

RESULTS

The refractive error was -0.20 ± 0.36 D at 1 month, -0.20 ± 0.35 D at 2 months (P = .503), -0.10 ± 0.37 D at 6 months (P < .001), -0.02 ± 0.38 D at 12 months (P < .001), 0.00 ± 0.38 D at 24 months (P < .001), and 0.03 ± 0.39 D at 36 months (P < .001). Multivariate analysis showed long-term, independent associations for young age (beta = -0.122; P = .029) and changes in mean keratometry (beta = -0.413; P < .001). A greater refractive change was associated with a greater change in UNVA (r = 0.134; P = .026) but not with UDVA (r = -0.029; P = .631) or CDVA (r = -0.010; P = .875).

CONCLUSIONS

Implantation of the PanOptix IOL yields stable clinical outcomes for visual acuity and refractive error for the first 3 years. A slight hyperopic shift, causing decreased near visual acuity, is anticipated for younger patients. [J Refract Surg. 2023;39(4):236-241.].

Comparing the accuracy of the new-generation intraocular lens power calculation formulae in axial myopic eyes: a meta-analysis

PURPOSE

To compare the accuracy of the new-generation intraocular lens power calculation formulae in axial myopic eyes.

METHODS

Four databases, PubMed, Web of Science, EMBASE and Cochrane library, were searched to select relevant studies published between Apr 11, 2011, and Apr 11, 2021. Axial myopic eyes were defined as an axial length more than 24.5 mm. There are 13 formulae to participate in the final comparison (SRK/T, Hoffer Q, Holladay I, Holladay II, Haigis for traditional formulae, Barrett Universal II, Olsen, T2, VRF, EVO, Kane, Hill-RBF, LSF for the new-generation formulae). The primary outcomes were the percentage of eyes with a refractive prediction error in ± 0.5D and ± 1.0D.

RESULTS

A total of 2273 eyes in 15 studies were enrolled in the final meta-analysis. Overall, the new-generation formulae showed a relatively more accurate outcome in comparison with traditional formulae. The percentage of eyes with a predictive refraction error in ± 0.5D (± 1.0D) of Kane, EVO and LSF was higher than 80% (95%), which was only significantly different from Hoffer Q (all P < 0.05). Moreover, another two new-generation formulae, Barrett Universal II and Olsen, had higher percentages than SRK/T, Hoffer Q, Holladay I and Haigis for eyes with predictive refraction error in ± 0.5D and ± 1.0D (all P < 0.05). In ± 0.5D group, Hill-RBF was better than SRK/T (P = 0.02), and Holladay I was better than EVO (P = 0.03) and LSF (P = 0.009), and Hoffer Q had a lower percentage than EVO, Kane, Hill-RBF and LSF (P = 0.007, 0.004, 0.002, 0.03, respectively). Barrett Universal II was better than T2 (P = 0.02), and Hill-RBF was better than SRK/T (P = 0.009). No significant difference was found in other pairwise comparison.

CONCLUSION

The new-generation formula is more accurate in intraocular lens power calculation for axial myopic eyes in comparison with the third- or fourth-generation formula.

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

Purpose

To compare the change in intraocular lens (IOL) axial movement, corneal power, and postoperative refraction of eyes implanted with two different single-piece, open loop, acrylic foldable IOLs with planar-haptic design: one IOL with hinges vs. one IOL without hinges. The role of IOL axial movement on short-term refractive shift after cataract surgery was also evaluated.

Methods

This retrospective comparative study enrolled consecutive patients who had phacoemulsification with aspheric IOL implantation. The IOL depth (the distance from corneal endothelium to IOL surface) and corneal power were measured via anterior-segment optical coherence tomography at 4 days and 1 month postoperatively. The changes in axial movement of the IOL, corneal power, and manifest refractive spherical equivalent (MRSE) were compared among groups, and the correlations between each lens were evaluated.

Results

IOL with hinges was implanted in 42 eyes of 42 patients and IOL without hinges was implanted in 42 eyes of 42 patients. The change in axial movement between 4 days and 1 month was significantly smaller in the IOL with hinges group than in the IOL without hinges group (p < 0.001). The axial movement of IOL with hinges did not correlate with the MRSE change; however, the forward shift of IOL without hinges correlated with the myopic refractive change (Pearson r = 0.62, p < 0.001).

Conclusion

The postoperative axial movement of IOL was more stable in the IOL with hinges group than the IOL without hinges group between 4 days and 1 month after cataract surgery. Even though the two study IOLs with planar-haptic design are made of similar acrylic materials, other characteristics such as hinge structure may affect IOL stability in the bag.

Comparison of Postoperative Stability of Intraocular Lenses after Phacovitrectomy for Rhegmatogenous Retinal Detachment

We retrospectively compared the stability of intraocular lenses (IOLs) routinely used at our institution by measuring IOL position after phacovitrectomy for rhegmatogenous retinal detachment (RRD). Patients with RRD who underwent phacovitrectomy with gas tamponade received one of three IOLs: 6-mm, single-piece NS-60YG (NIDEK, 15 eyes); 6-mm, single-piece XY1 (HOYA, 11 eyes); or 7-mm, three-piece X-70 (Santen, 11 eyes). Various parameters associated with the anterior chamber, lens, and IOL were measured by swept-source anterior segment optical coherence tomography (CASIA2; Tomey Corp) before and 1 week and 1 month after surgery. IOL position was determined as follows: IOL position = (postoperative aqueous depth [AQD] − preoperative AQD)/lens thickness. We found no significant difference in axial length between the IOLs (p = 0.97). At 1 week, IOL position was as follows: NS-60YG, 0.32; XY1, 0.24; and X-70, 0.26 (p < 0.05). The respective IOL positions at 1 month were 0.35, 0.27, and 0.28 (p < 0.01). These results indicated the smallest anterior shift with NS-60YG. To replicate the anterior shift of IOL position ex vivo, biomechanical measurement was performed. NS-60YG resisted more displacement force than the other IOLs. Thus, in eyes undergoing phacovitrectomy for RRD, NS-60YG was the most stable of the three IOLs studied.

Anterior chamber depth variability between 2 hydrophobic acrylic 1-piece intraocular lenses: randomized trial

PURPOSE

To analyze the difference in anterior chamber depth (ACD) after uneventful cataract surgery between 2 hydrophobic acrylic 1-piece intraocular lenses (IOLs) with different material properties.

SETTING

Hanusch Hospital, Vienna, Austria.

DESIGN

Single-center, bilateral randomized paired-eye controlled study.

METHODS

Patients scheduled for bilateral cataract surgery were randomized to receive the Clareon IOL in 1 eye and the AcrySof IQ IOL (both Alcon Laboratories, Inc.) in the contralateral eye. Preoperatively, a slitlamp examination, optical biometry (IOLMaster 700, Carl Zeiss Meditec AG), refraction, and visual acuity measurements were performed. ACD was assessed 1 hour and 1 week postoperatively and with additional measurement of uncorrected (UDVA) and corrected distance visual acuity (CDVA) 6 months postoperatively.

RESULTS

80 eyes of 40 patients were analyzed in this study. ACD at the 6-month follow-up was 3.94 ± 0.30 mm for the Clareon IOL and 3.91 ± 0.32 mm for the AcrySof IQ IOL (P = .08). Statistically significant differences in the ACD shift between both IOLs were detected between 1 week and 6 months (P = .04) and 1 hour and 6 months (P = .04). There were no statistically significant differences between both IOLs in UDVA (P = .78), CDVA (P = .59), and spherical equivalent (SE, P = .39) at the 6-month visit. The mean absolute error between the measured and the aimed SE was not significant (P = .97).

CONCLUSIONS

There was no clinically relevant difference in ACD between the Clareon IOL and the AcrySof IQ IOL in patients after uneventful cataract surgery. Both IOLs yielded good refraction and visual acuity outcomes.

Relationship Between Postoperative Intraocular Lens Shift and Postoperative Refraction Change in Cataract Surgery Using Three Different Types of Intraocular Lenses

Introduction

Understanding the relationship between postoperative intraocular lens (IOL) shift and refractive change is crucial for the accuracy of predicted postoperative refraction (PPR). We assessed the relationships between different IOL fixation methods, haptic designs, and several metrics.

Methods

Single-center, open-label study which included 69 eyes. We preoperatively measured the anterior chamber depth (ACD), lens thickness (LT), axial length (AL), and PPR. AcrySof IQ (n = 27) and FineVision (n = 24) were fixed in the bag, and FEMTIS (n = 18) was fixed in capsulorhexis. At 1 day, 1 week, and 1 month postoperatively, we checked the IOL position and refraction and compared the IOL shift, refraction change, and the margin of error of the predicted PPR (PR-PPR difference). We also analyzed the correlation between postoperative and preoperative variables.

Results

FEMTIS showed the highest stability in terms of IOL shift and refraction. The in-the-bag-fixated IOLs showed a significant forward shift between 1 day and 1 week postoperatively. There were significant differences in the PR-PPR difference between the IOLs. ACD and AL showed significant positive correlations, and LT showed a significant negative correlation with IOL shift and change in PR between 1 day and 1 week, but not between 1 week and 1 month postoperatively.

Conclusion

The relationship between postoperative IOL shift and refraction change varied according to IOLs with different haptic types. Capsulorhexis fixation may be more stable than in-the-bag fixation. Furthermore, preoperative ACD, LT, and AL may be useful factors to predict IOL shift, change in PR, and to a lesser extent the degree of the margin of error in clinical practice. Our findings may improve the accuracy of PPR and refractive outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-021-00390-x.

Intraocular lens optic edge design for the prevention of posterior capsule opacification after cataract surgery

BACKGROUND

Posterior capsule opacification (PCO) is a clouding of the posterior part of the lens capsule, a skin-like transparent structure, which surrounds the crystalline lens in the human eye. PCO is the most common postoperative complication following modern cataract surgery with implantation of a posterior chamber intraocular lens (IOL). The main symptoms of PCO are a decrease in visual acuity, 'cloudy', blurred vision and reduced contrast sensitivity. PCO is treated with a neodymium:YAG (Nd:YAG) laser to create a small opening in the opaque capsule and regain a clear central visual axis. This capsulotomy might cause further ocular complications, such as raised intraocular pressure or swelling of the central retina (macular oedema). This procedure is also a significant financial burden for health care systems worldwide. In recent decades, there have been advances in the selection of IOL materials and optimisation of IOL designs to help prevent PCO formation after cataract surgery. These include changes to the side structures holding the lens in the centre of the lens capsule bag, called IOL haptics, and IOL optic edge designs.

OBJECTIVES

To compare the effects of different IOL optic edge designs on PCO after cataract surgery.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, Ovid Embase, Latin American and Caribbean Health Sciences Literature Database (LILACS), the ISRCTN registry, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) up to 17 November 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared different types of IOL optic edge design. Our prespecified primary outcome was the proportion of eyes with Nd:YAG capsulotomy one year after surgery. Secondary outcomes included PCO score, best-corrected distance visual acuity (BCDVA) and quality of life score at one year. Due to availability of important long-term data, we also presented data at longer-term follow-up which is a post hoc change to our protocol.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane and the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We included 10 studies (1065 people, 1834 eyes) that compared sharp- and round-edged IOLs. Eight of these studies were within-person studies whereby one eye received a sharp-edged IOL and the fellow eye a round-edged IOL. The IOL materials were acrylic (2 studies), silicone (4 studies), polymethyl methacrylate (PMMA, 3 studies) and different materials (1 study). The studies were conducted in Austria, Germany, India, Japan, Sweden and the UK. Five studies were at high risk of bias in at least one domain. We judged two studies to be at low risk of bias in all domains. There were few cases of Nd:YAG capsulotomy at one year (primary outcome): 1/371 in sharp-edged and 4/371 in round-edged groups. The effect estimate was in favour of sharp-edged IOLs but the confidence intervals were very wide and compatible with higher or lower chance of Nd:YAG capsulotomy in sharp-edged compared with round-edged lenses (Peto odds ratio (OR) 0.30, 95% CI 0.05 to 1.74; I² = 0%; 6 studies, 742 eyes). This corresponds to seven fewer cases of Nd:YAG capsulotomy per 1000 sharp-edged IOLs inserted compared with round-edged IOLs (95% CI 9 fewer to 7 more). We judged this as low-certainty evidence, downgrading for imprecision and risk of bias. A similar reduced risk of Nd:YAG capsulotomy in sharp-edge compared with round-edge IOLs was seen at two, three and five years but as the number of Nd:YAG capsulotomy events increased with longer follow-up this effect was more precisely measured at longer follow-up: two years, risk ratio (RR) 0.35 (0.16 to 0.80); 703 eyes (6 studies); 89 fewer cases per 1000; three years, RR 0.21 (0.11 to 0.41); 538 eyes (6 studies); 170 fewer cases per 1000; five years, RR 0.21 (0.10 to 0.45); 306 eyes (4 studies); 331 fewer cases per 1000. Data at 9 years and 12 years were only available from one study. All studies reported a PCO score. Four studies reported the AQUA (Automated Quantification of After-Cataract) score, four studies reported the EPCO (Evaluation of PCO) score and two studies reported another method of quantifying PCO. It was not possible to pool these data due to the way they were reported, but all studies consistently reported a statistically significant lower average PCO score (of the order of 0.5 to 3 units) with sharp-edged IOLs compared with round-edged IOLs. We judged this to be moderate-certainty evidence downgrading for risk of bias. The logMAR visual acuity score was lower (better) in eyes that received a sharp-edged IOL but the difference was small and likely to be clinically unimportant at one year (mean difference (MD) -0.06 logMAR, 95% CI -0.12 to 0; 2 studies, 153 eyes; low-certainty evidence). Similar effects were seen at longer follow-up periods but non-statistically significant data were less fully reported: two years MD -0.01 logMAR (-0.05 to 0.02); 2 studies, 311 eyes; three years MD -0.09 logMAR (-0.22 to 0.03); 2 studies, 117 eyes; data at five years only available from one study. None of the studies reported quality of life. Very low-certainty evidence on adverse events did not suggest any important differences between the groups.

AUTHORS' CONCLUSIONS

This review provides evidence that sharp-edged IOLs are likely to be associated with less PCO formation than round-edged IOLs, with less Nd:YAG capsulotomy. The effects on visual acuity were less certain. The impact of these lenses on quality of life has not been assessed and there are only very low-certainty comparative data on adverse events.

Long-Term Changes in Manifest Refraction Subsequent to Cataract Surgery

PURPOSE

To examine the long-term refractive changes after stabilization of surgically induced changes (SICs) subsequent to cataract surgery.

SETTING

Private hospital.

DESIGN

Case-control study.

METHODS

Manifest refraction of 300 eyes of 300 patients that underwent phacoemulsification and 300 eyes of 300 age- and sex-matched patients without surgery was examined the day on which SICs stabilized (baseline) and ≥7 years postbaseline using an autorefractometer. Refraction was divided into 3 components: spherical power (M), vertical/horizontal astigmatism (J0), and oblique astigmatism (J45) using power vector analysis, and the components were compared between the 2 time-points and between groups.

RESULTS

In the surgery group, the mean M and J45 did not change significantly between baseline and ≥7 years postbaseline, but the J0 significantly decreased between the 2 time-points (P < .001), indicating an against-the-rule (ATR) shift. In the non-surgery group, the mean M significantly increased and J0 significantly decreased between the time-points (P < .001), whereas J45 did not change significantly. The mean change in M between the 2 time-points was significantly smaller in the surgery group (P < .001), whereas the changes in J0 and J45 did not differ significantly between the time-points.

CONCLUSION

Spherical power did not change and refractive astigmatism significantly changed toward ATR astigmatism during the more than 7-year follow-up after stabilization of SICs in pseudophakic eyes, while hyperopic and ATR shifts occurred in phakic eyes, and the astigmatic changes were comparable between pseudophakic and phakic eyes.

Effect of capsule tension ring on short-term refractive stabilization and visual performance in trifocal intraocular lens implantation

PURPOSE

To provide refractive stability and increase visual performance with the use of a capsular tension ring in trifocal intraocular lens implantation.

METHODS

This prospective randomized study was conducted in the Yeniyüzyıl university ophthalmology department between February 2018 and September 2019. Eighty-six eyes of 43 patients with visual loss due to uncomplicated cataract in both eyes were randomly divided into two groups, A and B. The eyes in both groups underwent refractive lens exchange with implantation of the same design of trifocal IOL (plate haptic design). In group B, a capsular tension ring was inserted into the capsular bag before trifocal IOL implantation. Both groups were examined at 1day, 1week, 1month, and 3months postoperatively. At 3months after surgery, visual acuity, refractive errors and refractive prediction errors were analyzed and compared between groups A and B.

RESULTS

The postoperative values in group A were spherical equivalent (mean±SD), 0.07±0.79 diopters (D); refractive sphere (mean±SD), 0.43±0.84 diopters (D); uncorrected distance acuity, 0.20±0.04 (logMAR); best-corrected distance acuity, 0±0.02 (logMAR). Group B values were 0.14±0.5 diopters (D), 0.61±0.45 diopters (D), 0.25±0.20 (logMAR), 0.01±0.04 (logMAR), respectively. There was no significant difference between the two groups with respect to the postoperative evaluation.

CONCLUSION

The use of CTR in the implantation of the trifocal intraocular lens had no statistically significant impact on refractive stability.

Effect of Capsular Tension Ring on Refractive Outcomes in Patients With Implantation of the Quadrifocal Acrysof PanOptix TFNT00 IOL

PURPOSE

To evaluate the effect of a capsular tension ring (CTR) on refractive outcomes in eyes undergoing implantation of the quadrifocal Acrysof PanOptix TFNT00 intraocular lens (IOL) (Alcon Laboratories, Inc).

METHODS

A retrospective case-control study was undertaken of 91 eyes implanted with the TFNT00 IOL. Of these 91 eyes, a CTR was implanted in 33 and these eyes were compared to the 58 eyes in which a CTR was not implanted. The main outcome measure was the mean absolute error (MAE) of the refractive prediction error. To evaluate the consistency of refractive outcomes, variance of MAE was measured. Using a swept-source optical coherence tomography device, postoperative aqueous depth (AQD) was measured to estimate the position of the IOL.

RESULTS

Eyes with a CTR showed a significantly smaller MAE when compared with eyes without a CTR (P = .038 at 1 m, P = .003 at 2 m, and P = .001 at 6 m). There was a lower variance of MAE in the eyes implanted with a CTR, with higher precision of refraction (P = .058 at 1 m, P = .007 at 2 m, and P = .001 at 6 m). There was a significant difference in the percentage of the eyes showing more than 0.50 D from the estimated target of the Barrett Universal II formula (P = .007 at 1 m, P = .064 at 2 m, and P = .004 at 6 m, respectively). AQD was significantly shallower in eyes with a CTR than in eyes without a CTR (P = .006).

CONCLUSIONS

Use of the CTR enhanced the accuracy of postoperative refractive outcomes after TFNT00 IOL implantation by preventing the posterior bowing of the optic-haptic junction. [J Refract Surg. 2021;37(3):174-179.].

Temporary changes of visual outcomes and anterior chamber parameters after phacoemulsification and low-add-power segmented intraocular lens implantation for primary angle closure disease

PURPOSE

To evaluate the temporary changes in visual outcomes and anterior segment parameters after cataract surgery plus low-add bifocal intraocular lens (IOL) implantation for primary angle closure disease (PACD).

METHODS

This retrospective comparative case-control study included two groups: low-add-power segmented IOL and monofocal IOL. Postoperative examination involved evaluation of uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), uncorrected intermediate visual acuity (UIVA), and spherical equivalent (SE). Anterior segment examination was performed using anterior segment optical coherence tomography.

RESULTS

This study included 19 eyes of 11 consecutive patients who underwent cataract surgery. The low-add group had better UDVA than the monofocal group at 3 months postoperatively, better UIVA at 1 month postoperatively, better UNVA at 1 week postoperatively. In the low-add group, SE increased at 1 and 3 months postoperatively compared with 1 week postoperatively. In the monofocal group, objective SE decreased at 1 and 3 months postoperatively compared with 1 week postoperatively. In the low-add group, the anterior chamber depth (ACD) became significantly deep gradually at 1 and 3 months compared with at 1 week postoperatively. In the monofocal group, the ACD became significantly shallow gradually at 1 and 3 months than at 1 week postoperatively.

CONCLUSION

The low-add-power segmented IOL achieved better far and intermediate distance visual acuity after cataract surgery in PACD patients than did the monofocal IOL. The ACD became deeper and SE showed a hyperopic shift with the low-add-power segmented IOL at 1 and 3 months after cataract surgery compared with at 1 week after cataract surgery.

Altered stress field of the human lens capsule after cataract surgery

The lens capsule of the eye is important in focusing light onto the retina during the process of accommodation and, in later life, housing a prosthetic lens implanted during cataract surgery. Though considerable modeling work has characterized the mechanics of accommodation, little has been done to understand the mechanics of the lens capsule after cataract surgery. As such, we present the first 3-D finite element model of the post-surgical human lens capsule with an implanted tension ring and, separately, an intraocular lens to characterize the altered stress field compared to that in a model of the native lens capsule. All finite element models employed a Holzapfel hyperelastic constitutive model with regional variations in anisotropy. The post-surgical lens capsule demonstrated a dramatic perturbation to the stress field with mostly large reductions in stresses (except at the equator where the implant contacts the capsule) compared to native, wherein maximal changes in Cauchy stress were -100% and -145% for the tension ring and intraocular lens, respectively. However, implantation of the tension ring produced a more uniform stress field compared to the IOL. The magnitudes and distribution of the perturbed stress field may be an important driver of the fibrotic response of inhabiting lens epithelial cells and associated lens capsule remodeling after cataract surgery. Thus, the mechanical effects of an implant on the lens capsule could be an essential consideration in the design of intraocular lenses, particularly those with an accommodative feature.

Short-Term Changes in Prediction Error after Cataract Surgery in Eyes Receiving 1 of 3 Types of Single-Piece Acrylic Intraocular Lenses

PURPOSE

To compare short-term changes in refractive prediction error (PE) after phacoemulsification among eyes receiving different types of single-piece acrylic intraocular lenses (IOLs).

DESIGN

Randomized clinical trial.

METHODS

A total of 195 eyes of 195 patients scheduled for implantation of a single-piece acrylic IOL were randomly assigned to receive 1 of 3 IOLs: 1) an Alcon model SN60WF, 2) a Hoya model XY-1, or 3) an AMO model ZCB00V. Manifest spherical equivalent (MRSE) value, PE, and changes in PE were examined at 1 day and at 1 and 2 months postoperatively and were compared among groups.

RESULTS

The mean MRSE and PE significantly changed toward myopia between 1 day and 2 months postoperatively in all groups (P < .0001). The MRSE and PE did not differ significantly among groups at 1 day and 1 month postoperatively and were significantly smaller in the SN60WF group than in the XY-1 and ZCB00V groups at 2 months (P ≤ .0006). The PE change between 1 day and 2 months postoperatively was significantly smaller in the SN60WF group than in the other groups (P = .0062). IOL type and changes in anterior chamber depth and corneal curvature independently correlated with PE changes.

CONCLUSIONS

The MRSE and PE showed a significant myopic change for 2 months postoperatively in eyes implanted with 1 of 3 types of single-piece acrylic IOLs and were significantly smaller in the SN60WF than in the XY-1 and ZCB00V groups. Changes in PE during the 2 postoperative months were smaller in the SN60WF IOLs than in the other IOLs, suggesting that postoperative refractive stability differs among single-piece acrylic IOLs.

Measurement of Force Required for Anterior Displacement of Intraocular Lenses and Its Defining Parameters

Intraocular stability during or after cataract and glaucoma filtration surgeries and vitreous surgery with a gas/silicone oil tamponade might differ among intraocular lenses (IOLs). We used six different one-piece IOL models and measured the force that displaced the IOLs from the vitreous cavity to anterior chamber as a measure of stability against the pressure gradient between the anterior and posterior IOL surfaces. We measured IOL hardness, haptics junction area, and posterior IOL bulge to identify what determines the IOL displacement force. The KOWA YP2.2 IOL (1.231 mN) required significantly greater force than the HOYA XY1 (0.416 mN, p = 0.0004), HOYA 255 (0.409 mN, p = 0.0003), Alcon SN60WF (0.507 mN, p = 0.0010), and Nidek NS60YG (0.778 mN, p = 0.0186) IOLs; J&J ZCB00V IOL (1.029 mN) required greater force than the HOYA XY1 (p = 0.0032) and HOYA 255 (p = 0.0029) IOLs; the Nidek NS60YG IOL required greater force than the HOYA 255 (p = 0.0468) IOL. The haptics junction area was correlated positively with the IOL displacement force (r = 0.8536, p = 0.0306); the correlations of the other parameters were non-significant. After adjusting for any confounding effects, the haptics junction area was correlated significantly with the IOL displacement force (p = 0.0394); the IOL hardness (p = 0.0573) and posterior IOL bulge (p = 0.0938) were not. The forces that displace IOLs anteriorly differed among one-piece soft-acrylic IOLs, and the optics/haptics junction area was the major force determinant.

Refractive stability of a new single-piece hydrophobic acrylic intraocular lens and corneal wound repair after implantation using a new automated intraocular lens delivery system

PURPOSE

To investigate refractive stability and characterize corneal incision repair up to 3 months after implantation of a new hydrophobic acrylic intraocular lens (IOL) with hydroxyethylmethacrylate using a new automated IOL delivery system.

METHODS

This prospective case series included 50 eyes of 50 patients undergoing phacoemulsification and implantation of the Clareon® CNA0T0 IOL using the AutonoMe® automated delivery system in the Department of Ophthalmology, Keio University School of Medicine. The clinical data were collected from 46 eyes of 46 patients preoperatively and 1 day, 1 week, and 1 and 3 months postoperatively. Endothelial-side incision gaping, posterior incision retraction, and Descemet's membrane detachment were recorded as present or absent using anterior-segment optical coherence tomography postoperatively.

RESULTS

The uncorrected distance and corrected distance visual acuities improved and stabilized 1 week postoperatively. The anterior chamber depth was stable from 1 week postoperatively. The subjective refraction was stable from 1 day postoperatively. Descemet's membrane detachments and endothelial-side wound gaping were seen in 19 (41.3%) eyes and 34 (73.9%) eyes 1 day postoperatively and decreased gradually. Posterior incision retraction was seen in eight eyes (17.4%) on day 1 and increased to 19 eyes (41.3%) 3 months postoperatively.

CONCLUSIONS

The Clareon IOL had excellent refractive stability from day 1 postoperatively. The AutonoMe automated delivery system enables safe IOL implantation through a 2.4-mm corneal incision, although the wound required longer than 1 month to heal postoperatively.

Update on Intraocular Lens Power Calculation Study Protocols: The Better Way to Design and Report Clinical Trials

It was almost 40 years ago when one of the authors (K.J.H.) published an organized system to quantify the accuracy of intraocular lens (IOL) power calculation formulas, methods, and instruments. At the behest of the editor of the American Journal of Ophthalmology, the IOL Power Club (along with a statistician) published an editorial in 2015 modernizing and quantifying the proper protocols for these studies. Over the past decade, so many new optical biometers, formulas, and methods (whose accuracies have yet to be completely tested) have been introduced that we were asked to modernize and update these guidelines yet again to help others design and report correctly the results of clinical studies on IOL power calculation and biometry for 2020. We evaluated guidelines to enroll patients, including visual acuity minimums, exclusion of bilateral eyes, sample size issues, demographics (age, gender, and ethnicity), and whether such studies should not be performed using the same data that were used to develop the formula being tested. We showed the absolute need for constant optimization, which formulas should be tested for comparison, refraction measurement (testing distance), as well as the analysis of the prediction error (median and mean absolute errors; standard deviation; range of errors; percentage of eyes with a prediction within ±0.25 diopter [D], ±0.50 D, ±0.75 D, and ±1.00 D; and interquartile displays) and statistical methods of analyses. We present methods of ranking formula accuracy, including the new Haigis IOL Formula Performance Index. We also point out the issues of who programmed the formulas being tested, that all formulas used in the study must be referenced, and the software version number of all instruments used in the study should be stated clearly. The definition of anterior chamber depth should be stated as measured from the corneal epithelium to the lens. We hope that these recommendations will help researchers to improve the validity and accuracy of their studies with the ultimate goal to improve the accuracy of IOL power calculation.

Comparison of postoperative axial stability of intraocular lens and capsulotomy parameters between precision pulse capsulotomy and continuous curvilinear capsulotomy: A prospective cohort study

OBJECTIVES

The aim of this study was to verify the safety and stability of precision pulse capsulotomy (PPC) by comparison of the axial stability of the intraocular lens (IOL) and the capsulotomy parameters during 6 months of follow-up after cataract surgery using PPC or the conventional method (continuous curvilinear capsulorhexis, CCC).

DESIGN

Prospective observational study.

SETTING

Tertiary referral center.

SUBJECTS

Fifty nine eyes of 59 candidates for cataract surgery.

INTERVENTIONS

PPC (33 eyes) or CCC (26 eyes).

OUTCOME MEASURES

The anterior capsule opacification grade and effective lens position (ELP) were measured 1 week and 1, 3, and 6 months postoperatively.

RESULTS

No significant difference in the mean anterior capsule opacification grade or the effective lens position was found between the PPC and CCC groups at any time point; however, the standard deviation and root mean square of the effective lens position were significantly lower in the PPC group than in the CCC group during follow-up (P = .002 and P = .011, respectively). There was a significantly lower discrepancy between the intended vs achieved capsulotomy area and better circularity in the PPC group than in the CCC group at all time points.

CONCLUSIONS

The overall variability in effective lens position was less when cataract surgery was performed using PPC than when performed using CCC. Circularity was better and had a more predictable size with PPC than with CCC.

Intraocular lens power formula accuracy: Comparison of 7 formulas

PURPOSE

To assess the accuracy of 7 intraocular lens (IOL) power formulas (Barrett Universal II, Haigis, Hoffer Q, Holladay 1, Holladay 2, SRK/T, and T2) using IOLMaster biometry and optimized lens constants.

SETTING

Public hospital ophthalmology department.

DESIGN

Retrospective case series.

METHODS

Data from patients having uneventful cataract surgery with Acrysof IQ SN60WF IOL implantation over 5 years were obtained from the biometry and patient charts. Optimized lens constants were calculated for each formula and used to determine the predicted refractive outcome for each patient. This was compared with the actual refractive outcome to give the prediction error. Eyes were separated into subgroups based on axial length (AL) as follows: short (≤22.0 mm), medium (>22.0 to <24.5 mm), medium long (≥24.5 to <26.0 mm), and long (≥26.0 mm).

RESULTS

The study included 3241 patients. The Barrett Universal II formula had the lowest mean absolute prediction error over the entire AL range (P < .001, all formulas) as well as in the medium (P < .001, all formulas), medium-long (P < .001, except Holladay 1 and T2), and long AL (P < .001, except T2) subgroups. No statistically significant difference was seen between formulas in the short AL subgroup. Overall, the Barrett Universal II formula resulted in the highest percentage of eyes with prediction errors between ±0.25 diopter D, ±0.50 D, and ±1.00 D.

CONCLUSION

In eyes with an AL longer than 22.0 mm, the Barrett Universal II formula was a more accurate predictor of actual postoperative refraction than the other formulas.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Effects of Residual Anterior Lens Epithelial Cell Removal on Axial Position of Intraocular Lens after Cataract Surgery

Purpose

The aim of this study was to assess the effects of residual anterior lens epithelial cell (LEC) removal by anterior capsule polishing on the effective lens position (ELP) and axial position stability of the intraocular lens (IOL) after cataract surgery via postoperative measurement of the anterior chamber depth.

Methods

We enrolled 30 patients (60 eyes) requiring bilateral cataract surgery for age-related cataracts. Meticulous anterior capsule polishing and removal of residual LECs under the capsule were performed using a bimanual irrigation/aspiration system for one randomly selected eye in each patient. The eye without polishing served as a control. ELP was measured at five different time points after surgery, and axial shifting of IOL was determined at each visit by comparison with the position at the previous visit.

Results

The polishing and control groups showed significant differences with regard to the mean ELP at 1 (3.40 ± 0.29 versus 3.53 ± 0.32 mm, resp.; p=0.026) and 2 months (3.42 ± 0.32 versus 3.61 ± 0.35 mm, resp.; p=0.001) after surgery, the mean standard deviation for the five ELP values (0.087 ± 0.093 versus 0.159 ± 0.138 mm, p=0.001), and the root mean square of the change in ELP at each follow-up visit (0.124 ± 0.034 versus 0.246 ± 0.038 mm, p=0.047). The eyes in the control group exhibited a tendency for backward IOL movement with a concurrent hyperopic shift in refraction of approximately 0.2 diopter at 2 months after surgery.

Conclusion

Our findings suggest that residual anterior LEC polishing enhances the axial position stability of IOLs, without any complications, after cataract surgery.

Evaluation of the anterior segment parameters after Nd: YAG laser Capsulotomy: Effect the design of intraocular lens Haptic

Objective:

To evaluate the changes in anterior segment parameters after neodymium–yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy in 1-piece and 3-piece IOLs.

Methods:

In an institution, 65 eyes of 65 consecutive pseudophakic patients with posterior capsule opacification underwent Nd:YAG laser capsulotomy. The patients were divided into two groups according to the IOL type. Group-1 consisted of 35 subjects with 1-piece IOL and Group-2 consisted of 30 subjects with 3-piece IOL. Anterior segment parameters were measured with the Sirius rotating camera before, one week and one month after Nd:YAG laser capsulotomy.

Results:

Mean age was 72.3±5.2 years in 1-piece IOL and 72.3±6.8 years in 3-piece IOL. There were no statistically significant differences before capsulotomy for IOP, axial length, spherical equivalent, anterior chamber depth, central corneal thickness, anterior chamber angle and anterior chamber volume between two IOL groups. BCVA improved after capsulotomy in both groups (p=0.001). Both IOL groups had statistically significant myopic shift compared with the baseline values (P= 0.03 and P=0.01 resp.). Both IOL groups had statistically significant decrease in ACD, from baseline to the 1st week and 1^st month (p=0.04 and 0.03 resp.).

Conclusion:

To achieve the highest percentage of refractive and anterior segment stability surgeons may prefer to implant the 1-piece IOL design.

Comparison of Nd: YAG capsulotomy rate between 1-piece and 3-piece acrylic intraocular lenses: A STROBE-compliant article

The aim of the study is to compare Nd:YAG capsulotomy rate between acrylic 1- and 3-piece intraocular lenses. Among 924 eyes of 762 patients who received cataract surgery, we selected the 303 patients (404 eyes) implanted with an SN60WF 1-piece intraocular lens (Alcon, Fort Worth, TX) or a YA-60BBR 3-piece intraocular lens (Hoya Co., Tokyo, Japan). For intraindividual comparison, we enrolled the 17 patients implanted with an SN60WF in 1 eye and a YA-60BBR in the contralateral eye. We compared Nd:YAG capsulotomy rate between acrylic 1- and 3-piece intraocular lenses 24 months after the operation. Of the 404 eyes in this study, Nd:YAG capsulotomy was performed in 20 of 268 eyes (7.5%) in the SN60WF 1-piece intraocular lens group and 24 of 136 eyes (17.6%) in the YA-60BBR 3-piece intraocular lens group; the difference was statistically significant (P = .002). Among the 17 patients (34 eyes) who were implanted with 2 different inraocular lenses, Nd:YAG capsulotomy was performed in only 2 eyes (12%) in the SN60WF group and 9 eyes (53%) in the YA-60BBR group; the difference was statistically significant (P = .020).The authors found a significantly greater incidence of Nd:YAG capsulotomy in eyes who received 3-piece lenses compared with those who received 1-piece lenses.

Postoperative posterior capsular striae and the posterior capsular opacification in patients implanted with two types of intraocular lens material

AIM

To evaluate the incidence of postoperative posterior capsular striae (PCS) and its influence on posterior capsular opacification (PCO) in patients implanted with two types of lens material.

SETTING

Tertiary eye care center in central rural India.

STUDY DESIGN

A prospective, observational, nonrandomized study.

MATERIALS AND METHODS

The study included 1247 patients having age-related cataract scheduled for removal by phacoemulsification technique and implantation of hydrophilic or hydrophobic intraocular lens (IOL). Demographic profile, nuclear grading, axial length, and IOL power were noted. Details of PCS were noted on the 1st postoperative day in patients with clear cornea. Postoperative follow-up was ensured to study the status of PCS and development of PCO.

RESULTS

The overall incidence of PCS was 19.8% (247 out of 1247 eyes). Out of 1247 patients, 641 patients (51.4%) had hydrophilic IOL implantation and 201 eyes had PCS (31.4%) and 606 patients (48.6%) had hydrophobic IOL implantation and 46 eyes had PCS (7.6%), P = 0.04. Three and more striae were seen in 119 eyes (119/641, 18.6%) in hydrophilic group and 4 eyes (4/606, 0.66%) in hydrophobic group. Sixty-two eyes (62/201, 30.9%) in hydrophilic group with multiple PCS were reported with persistent striae after 6 months of surgery. Two eyes in hydrophobic group had persistent striae even after 3 years of follow-up. Evaluation of PCO score of the hydrophilic group was 0.6 whereas of the hydrophobic group was 0.1 (P = 0.04). Ten patients of the hydrophilic group only required neodymium-doped yttrium aluminum garnet (ND: YAG) laser capsulotomy.

CONCLUSION

The incidence of PCS was higher in hydrophilic than hydrophobic IOLs. Multiple PCS persisting in patients beyond 6 months after operation should be followed up for early development of PCO, particularly in patients implanted with hydrophilic IOL.

Accuracy of optical biometry combined with Placido disc corneal topography for intraocular lens power calculation

PURPOSE

To investigate the accuracy of a new optical biometer for intraocular lens (IOL) power calculation in eyes undergoing cataract surgery.

METHODS

Consecutive eyes of patients undergoing cataract surgery with the same IOL model were enrolled in a prospective cohort study. Axial length (AL) and corneal power were measured with an optical biometer based on optical low-coherence interferometry and Placido-disc corneal topography. IOL power was calculated with the Hoffer Q, Holladay 1 and SRK/T formulas. For each formula the lens constant was optimized in retrospect in order to achieve a mean prediction error (PE) of zero (difference between the predicted and the postoperative refraction). Median absolute error (MedAE) and percentage of eyes with PE ±0.50 D were calculated.

RESULTS

Seventy-four eyes of 74 cataract patients were enrolled. The MedAE was 0.25 D with all formulas. A PE within ±0.50 D was obtained in 89.04% of cases with the Hoffer Q and SRK/T formulas, and in 87.67% of cases with the Holladay 1 formula.

CONCLUSIONS

The optical biometer investigated in the present study provides accurate measurements for IOL power calculation.

Personal A-constant in relation to axial length with various intraocular lenses

PURPOSE

To study the relationship between the axial length and personal A-constant for the 1-piece Tecnis (Abbott ZCB00), AcrySof MA60AC (Alcon) and the Quatrix aspheric preloaded (CROMA) intraocular lenses (IOL).

MATERIALS AND METHODS

Patients matching the inclusion criteria were further subdivided according to the implanted IOL in this prospective comparative study. The obtained refractive outcomes were introduced into the formula installed in the biometry machine (Humphrey model 820 ultrasonic biometer) to obtain the personal A-constant for each eye. Polynomial regression analysis was done to study the individualized A-constant for each type of IOL in relation to preoperative axial length measurement.

RESULTS

Two hundred and forty five eyes of 186 patients were enrolled into this study, of whom 73 eyes with Tecnis 1-piece, 116 eyes with MA60AC, and 56 eyes with Quatrix. The median of personalized A-constant for Tecnis 1-piece, MA60AC, and Quatrix were 119.21 (SD 1.3, Std. Mean error 0.15), 119 (SD 1.2, Std. Mean error 0.11) and 120.4 (SD 1.2, Std. Mean error 0.16) respectively. Regression plots for the same range of axial length among all the groups showed that the Tecnis1 group followed the same pattern of the Quatrix group in which there was a linear relationship of a trend towards myopia when the axial length had increased and a hyperopic shift when decreased. This relationship changed into a plateau when the axial length became in the range of 23.5 mm to 27 mm in the MA60AC group.

CONCLUSIONS

Personal A-constant follows different trends with different IOLs even for the same range of axial length.

Comparison of refractive error in phacovitrectomy for epiretinal membrane using ultrasound and partial coherence interferometry

PURPOSE

To compare the postoperative refractive error (RE) using A-scan ultrasound (US) and partial coherence interferometry (PCI) after phacovitrectomy for idiopathic epiretinal membrane (iERM) and cataract.

METHODS

Eighty-eight participants (88 eyes) with iERM and cataracts underwent phacovitrectomies with internal limiting membrane removal. Postoperative RE was the main outcome measured, calculated by subtracting intended spherical equivalent (SE) from 6-month postoperative SE. Secondary outcomes included axial length (AL) measured by 2 methods, change in best-corrected visual acuity (BCVA), and change in central subfield thickness (CSFT).

RESULTS

Mean postoperative RE using US showed greater myopic shift compared with that using PCI (-0.569 ± 0.571 D vs -0.169 ± 0.415 D, respectively, p&lt;0.001). The 6-month postoperative RE was within ±0.50 D in 43.2% (38/88) using US vs 84.1% (74/88) using PCI and within ±1.00 D in 84.1% (74/88) using US vs 96.6% (85/88) using PCI. Mean AL measured by US was shorter than that measured by PCI (23.50 ± 1.27 mm vs 23.58 ± 1.30 mm, respectively, p&lt;0.001). Postsurgery, BCVA improved from 0.374 ± 0.264 logMAR to 0.144 ± 0.124 logMAR (p&lt;0.001), and CSFT decreased from 449.2 ± 78.5 µm to 378.2 ± 47.0 µm (p&lt;0.001). The BCVA improvement significantly correlated with decreased CSFT (R = 0.268, p = 0.011).

CONCLUSIONS

Estimation of intraocular lens power for phacovitrectomies for iERM and cataracts is more accurate when assessed by PCI than by US.

Comparison of Ocular Aberrations in Two Hydrophobic and Hydrophilic Intraocular Lenses

OBJECTIVE

To compare differences in higher-order aberrations (HOAs) between two standard spherical monofocal intraocular lenses (IOLs), the hydrophobic acrylic Alcon SA60AT (Bausch & Lomb), and hydrophilic acrylic Rayner Superflex (620H) (Rayner).

METHODS

In this case series, sixty-eight eyes of 68 patients who underwent phacoemulsification cataract surgery were studied. In group 1 (n=39), the hydrophobic Alcon SA60AT IOL, and in group 2 (n=29), the hydrophilic Rayner Superflex (620H) IOL, were implanted. Distant best-corrected visual acuity was 20/20. Aberrometry was performed by the OPD Scan III (Nidek) on the undilated pupil and under mesopic conditions at the first and third months after surgery.

RESULTS

There were no differences between the two groups in the mean total coma, total trefoil, total spherical aberration, and total HOAs in the two follow-up sessions (P>0.5, Independent t test). According to the repeated measure analysis of variance test results, total coma, total trefoil, total spherical aberration, and total HOAs significantly increased over time (P=0.033, P=0.017, P=0.005, P=0.004, respectively), although these changes were not significant between the two groups.

CONCLUSION

It seems that IOL optically behaves differently in vivo versus in vitro conditions and environmental factors can affect the increase or decrease in HOAs by an IOL. Therefore, we should consider these factors and the effect of IOL material and design. Also, the implantation of the Alcon SA60AT and Rayner Superflex IOL does not induce higher HOAs in pseudophakic versus phakic eyes.

Postoperative IOL Axial Movements and Refractive Changes After Femtosecond Laser-assisted Cataract Surgery Versus Conventional Phacoemulsification

PURPOSE

To evaluate intraocular lens (IOL) axial movements and refractive changes during a 6-month follow-up period after femtosecond laser-assisted cataract surgery and conventional cataract surgery, investigate the influence of capsulorhexis features on postoperative IOL axial changes, and assess the prediction error for both techniques.

METHODS

Eighty eyes of 80 candidates for cataract extraction were randomized into two groups: femtosecond laser (40 eyes) and manual (40 eyes).

RESULTS

The overall anterior chamber depth variation was significantly lower in the femtosecond laser group compared to the manual group during follow-up (P<.001). At 30 and 180 days postoperatively, the mean spherical equivalent showed a hyperopic shift (0.09±0.28 diopters [D]) in the femtosecond laser group and a myopic shift in the manual group (-0.25±0.18 D). Median absolute error was not significantly different between the two groups with standard formulas ranging between 0.29 and 0.64 (Hoffer Q) in the femtosecond laser group and between 0.24 (SRK-T) and 0.55 D (Hoffer Q) in the manual group. There was a significant lower deviation from intended versus achieved capsulotomy/capsulorhexis area in the femtosecond laser group (P<.001) compared to the manual group. The femtosecond laser group showed better IOL centration compared to the manual group at all time periods (P<.001).

CONCLUSIONS

Femtosecond laser-assisted cataract surgery was related to a lower overall variability of anterior chamber depth compared to conventional cataract surgery with more stable postoperative refraction. The two techniques did not show significant differences of prediction error.

Influence of corneal asphericity on the refractive outcome of intraocular lens implantation in cataract surgery

PURPOSE

To evaluate the possible influence of anterior corneal surface asphericity on the refractive outcomes in eyes having intraocular lens (IOL) implantation after cataract surgery.

SETTING

Fondazione G.B. Bietti IRCCS, Rome, Italy.

DESIGN

Retrospective comparative case series.

METHODS

Intraocular lens power was calculated using the Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. Asphericity (Q-value) was measured at 8.0 mm with a Placido-disk corneal topographer (Keratron), a rotating Scheimpflug camera (Pentacam), and a rotating Scheimpflug camera combined with Placido-disk corneal topography (Sirius). The relationship between the error in refraction prediction (ie, difference between expected refraction and refraction measured 1 month after surgery) and the Q-value was assessed by linear regression.

RESULTS

The same IOL model (Acrysof SA60AT) was implanted in 115 eyes of 115 consecutive patients. Regression analysis showed a statistically significant relationship between the error in refraction prediction and the Q-value with all formulas and all devices. In all cases, a more negative Q-value (prolate cornea) was associated with a myopic outcome, whereas a more positive Q-value (oblate cornea) was associated with a hyperopic outcome. The highest coefficient of determination was detected between the Hoffer Q formula and the Placido-disk corneal topographer (R(2) = 0.2630), for which the error in refraction prediction (y) was related to the Q-value (x) according to the formula y = -0.2641 + 1.4589 × x.

CONCLUSION

Corneal asphericity influences the refractive outcomes of IOL implantation and should be taken into consideration when using third-generation IOL power formulas.

FINANCIAL DISCLOSURE

Dr. Hoffer receives book royalties from Slack, Inc., Thorofare, New Jersey, and formula royalties from all manufacturers using the Hoffer Q formula. No other author has a financial or proprietary interest in any material or method mentioned.

Influence of intraocular lens haptic design on refractive error

PURPOSE

To assess the influence of intraocular (IOL) haptic design on the refraction prediction error in patients having cataract surgery.

SETTING

Private practice.

DESIGN

Comparative case series.

METHODS

Corneal power and axial length were measured with the same devices in eyes with a 3-piece Acrysof IOL and eyes with a 1-piece Acrysof IOL and were entered into the Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. The median absolute error and mean absolute error in refraction prediction (ie, difference between expected refraction and actual refraction) were assessed 1 month postoperatively.

RESULTS

The study evaluated 110 eyes with the 3-piece IOL and 84 eyes with the 1-piece IOL. With all formulas, the median absolute error was lower with the 3-piece IOL. It ranged between 0.15 diopter (D) (Haigis and Holladay 1) and 0.19 D (SRK/T) with the 3-piece IOL and between 0.23 D (Haigis) and 0.30 D (SRK/T) with the 1-piece IOL. With all formulas, a higher percentage of eyes with the 3-piece IOL were within ±0.25 D and ±0.50 D of the target refraction.

CONCLUSIONS

Three-piece IOLs may yield better refractive outcomes than 1-piece IOLs. A possible reason is that once the early forward IOL shift previously observed with the 3-piece design occurs because of the haptic-compression force decay typical of these IOLs, the rigid haptics of 3-piece IOLs still exert more pressure against the capsular bag than the haptics of 1-piece IOLs. Therefore, 3-piece IOLs may better resist subsequent capsule contraction and provide a more predictable effective lens position.

FINANCIAL DISCLOSURE

Dr. Hoffer receives royalties for his book IOL Power, Slack, Inc., and formula royalties from all manufacturers using the Hoffer Q formula. No other author has a financial or proprietary interest in any material or method mentioned.

Comparison of posterior capsule opacification at 360-degree square edge hydrophilic and sharp edge hydrophobic acrylic intraocular lens in diabetic patients

AIM

To compare posterior capsule opacification (PCO) degree and visual functions after phacoemulsification in eyes implanted with 360-degree square edge hydrophilic acrylic intraocular lens (IOL) (570C C-flex, Rayner) and sharp edge hydrophobic acrylic IOL (Sensar AR40e, AMO) in diabetic patients.

METHODS

Sixty diabetic patients underwent uneventful phacoemulsification and randomly implanted one of the two IOLs. The PCO value was measured by retroillumination photographs and Evaluation of Posterior Capsule Opacification (EPCO) 2000 image-analysis software at 1, 6, 12, and 24mo after surgery. Visual acuity, and contrast sensitivity in photopic and mesopic conditions were also examined at each follow up time point. The incidence of eye that required Nd:YAG laser posterior capsulotomy were also compared.

RESULTS

There was not any statistically significant difference in PCO scores between Rayner C-flex 570C group and Sensar AR40e group at each follow up time point. Visual acuity, Nd:YAG capsulotomy incidence and contrast sensitivity also had no significant difference during the 24mo follow-up.

CONCLUSION

For diabetic patients, Rayner 570C C-flex and Sensar AR40e IOLs are same effective for prevent PCO. The 360-degree square edge design maybe is a good alternative technique to improve PCO prevention.

Prospective Comparison of One-Piece and Three-Piece Tecnis Aspheric Intraocular Lenses: 1-year Stability and its Effect on Visual Function

PURPOSE

To compare the stability and visual function of one-piece hydrophobic intraocular lens (IOL) (ZCB00, Abbot Medical Optics) and a three-piece hydrophobic IOL (ZA9003, Abbot Medical Optics) after cataract surgery.

MATERIALS AND METHODS

Eighteen eyes of 18 patients with the one-piece IOL and 20 eyes of 20 patients with the three-piece IOL who underwent cataract surgery were evaluated prospectively on best corrected distance visual acuity, postoperative refractive error, IOL decentration and tilt, anterior chamber depth (ACD), spherical aberration and contrast sensitivity. Measurements were performed 1 week and 1, 3, 6 and 12 months postoperatively. The postoperative outcomes were compared between the two groups.

RESULTS

In the one-piece group, a hyperopic refractive error (p < 0.002) and deeper ACDs during 1-year post-operatively were observed compared with the three-piece group. There were no significant differences in BCVA, IOL tilt, spherical aberration or contrast sensitivity.

CONCLUSIONS

The stability of the one-piece IOL was greater than that of the three-piece IOL. The postoperative ACD and refractive error demonstrated that an anteriorly offset haptic in the one-piece IOL allowed incremental fixation to the posterior capsule.

Economic considerations related to choice of intraocular lens (IOL) and posterior capsule opacification frequency - a comparison of three different IOLs

PURPOSE

To evaluate the posterior capsule opacification (PCO) rates in three different modern standard intraocular lenses (IOL) and analyse the related cost.

METHODS

Retrospective study of medical records from 1527 patients who underwent uneventful cataract surgery by phacoemulsification with posterior chamber implantation of either AcrySof SN60 (n = 375), Akreos Adapt (n = 350) or Tecnis Acryl IOL (n = 801). All surgeries were performed by the same surgeon using the same surgical technique and equipment. Primary end-point was neodymium:yttrium-aluminium-garnet (Nd:YAG) capsulotomy for visual impairment secondary to PCO. Cost of IOL material and Nd:YAG capsulotomy for PCO was then evaluated and compared between the IOLs.

RESULTS

Mean follow-up was 41.5 months, and the only statistically significant variable of developing PCO was IOL type and individual follow-up time. Nd:YAG capsulotomy was performed in 7.47% in the AcrySof group, 17.71% in the Akreos group and 3.75% in the Tecnis group. Average cost for Nd:YAG capsulotomy per surgery was €18.75 in the AcrySof SN60 group, €44.25 in the Akreos Adapt group and €9.25 in the Tecnis Acryl group. The combined cost of cataract surgery and PCO treatment was €9.81 higher in for the Akreos Adapt group than the other two combined.

CONCLUSIONS

This retrospective study shows that the risk of PCO and Nd:YAG capsulotomy is significantly higher in hydrophilic Akreos IOL compared with both AcrySof and Tecnis hydrophobic IOLs. The increased risk of PCO in the hydrophilic IOL is related to higher total average costs for cataract surgery.

Intraocular lens power calculation by ray-tracing after myopic excimer laser surgery

PURPOSE

To investigate the refractive outcomes of intraocular lens (IOL) power calculation by ray-tracing after myopic excimer laser surgery.

DESIGN

Prospective, interventional case series.

METHODS

setting: Multicenter study. participants: Twenty-one eyes of 21 patients undergoing phacoemulsification and IOL implantation after myopic laser in situ keratomileusis or photorefractive keratectomy were enrolled. intervention: IOL power calculation was performed using internal software of a Scheimpflug camera combined with a Placido disc corneal topographer (Sirius; CSO). Exact ray-tracing was carried out after the axial length (measured either by immersion ultrasound biometry or partial coherence interferometry), target refraction, and pupil size had been entered. main outcome measures: Median absolute error, mean absolute error, and mean arithmetic error in refraction prediction, that is, the difference between the expected refraction (as calculated by the software) and the actual refraction 1 month after surgery.

RESULTS

The mean postoperative refraction was -0.43 ± 1.08 diopters (D), with a range between -1.28 and 0.85 D. The mean arithmetic error was -0.13 ± 0.49 D. The median and mean absolute errors were +0.25 D and 0.36 D, respectively. Also, 71.4% of the eyes were within ± 0.50 D of the predicted refraction, 85.7% were within ± 1.00 D, and 100% within ± 1.50 D.

CONCLUSIONS

Ray-tracing can calculate IOL power accurately in eyes with prior myopic laser in situ keratomileusis and photorefractive keratectomy, with no need for preoperative data.

Comparison of methods to measure corneal power for intraocular lens power calculation using a rotating Scheimpflug camera

PURPOSE

To assess the accuracy of corneal power measurements provided by a Scheimpflug camera (Pentacam HR) for intraocular lens (IOL) power calculation in unoperated eyes and compare the results with those of simulated keratometry (SimK) performed with a Placido-disk corneal topographer (Keratron).

SETTING

Private practice.

DESIGN

Evaluation of diagnostic test.

METHODS

Eight Scheimpflug camera corneal power measurements were analyzed: (1) average K, (2) true net power calculated using the Gaussian optics formula, (3) total corneal refractive power at 2.0 mm calculated by ray tracing on a ring and (4) as the average of the zone inside the ring, (5) total corneal refractive power at 3.0 mm on a ring and (6) as the average of the zone inside the ring, (7) the equivalent K reading at 3.0 mm and (8) at 4.5 mm. The IOL power was calculated using the Hoffer Q, Holladay 1, and SRK/T formulas.

RESULTS

No statistically significant differences were observed between any corneal power measurements, including simulated K, in 41 consecutive patients. The latter showed slightly lower mean absolute errors with all 3 formulas (range 0.26 to 0.27 diopter [D]). The Scheimpflug camera gave the lowest median absolute errors with all formulas; that is, the 3.0 mm equivalent K reading with the Hoffer Q formula (0.18 D) and Holladay 1 formula (0.17 D) and the 2.0 mm total corneal refractive power ring with the SRK/T formula (0.18 D).

CONCLUSION

Corneal power measurements provided by the Scheimpflug camera and Placido disk corneal topographer displayed comparable accuracy in IOL power calculation.

Effect of a single-piece and a three-piece acrylic sharp-edged IOL on posterior capsule opacification

BACKGROUND

To compare the intensity of posterior capsule opacification (PCO) between two intraocular lenses (IOLs) of the same optic material, but with different haptic design (1-piece vs. 3-piece).

METHODS

This prospective intraindividual controlled cohort study comprised eighty eyes of 40 patients with bilateral age-related cataract. Each patient received a Polylens Y10 (Polytech, Germany) 1-piece IOL in 1 eye and a Polylens Y30 (Polytech, Germany) 3-piece IOL in the contralateral eye. The IOL type in the first operated eye was randomly assigned before patient recruitment. Digital slitlamp photographs were taken 1 year postoperatively using a standardized photographic technique for regeneratory PCO. The amount of PCO was assessed subjectively at the slitlamp and objectively using automated image-analysis software.

RESULTS

The Polylens Y10 (1-piece) group showed significantly higher regeneratory and fibrotic PCO scores 1 year after surgery in subjective slitlamp evaluation, however not with objective evaluation using automated image-analysis software. Subjective PCO assessment resulted in a mean PCO score (scale = 0-10) of 1.6 in the Polylens Y10 group and 0.6 in the Polylens Y30 group at 1 year (p < 0.05). The mean automated image-analysis software PCO score was 1.5 in the Polylens Y10 group and 0.9 in the Polylens Y30 group (p = 0.6).

CONCLUSION

Both investigated IOLs showed good clinical performance regarding PCO, BCVA and IOL-centration. The Polylens Y10 IOL showed slightly more regeneratory PCO than the 3-piece acrylic IOL 1 year after surgery.