Comparisons of the in-the-bag stabilities of single-piece and three-piece intraocular lenses for age-related cataract patients: a randomized controlled trial

[Intraoperative Complications in Cataract Surgery]

Cataract surgery is frequently and successfully performed in the developed world. The indications for the operation have shifted on one hand towards healthier patients seeking freedom from glasses and on the other hand towards more complex cases. How should the patient be informed? What complications can occur intraoperatively, and what treatment options are available for these complications?This article offers a focus on conditions such as zonulopathy and pseudoexfoliation that can pose challenges to cataract surgery. It discusses the use of specialized tools such as capsular tension rings and capsular hooks and precise maneuvers to minimize stress on weakened zonules in order to ensure in-the-bag fixation of the IOL.Furthermore, the article addresses appropriate actions towards intraoperative complications such as anterior or posterior capsule ruptures and loss of nuclear fragments into the vitreous cavity.Exploring innovative advancements, this article presents the latest alternatives for intracapsular lens fixation, such as sutureless scleral fixation and emerging lens designs in cases where there is insufficient capsular support.Ultimately, the primary objective remains delivering optimal outcomes even for complex cases, and minimizing post-surgical issues. Numerous tools and techniques are available.

Postoperative intraocular lens stability following cataract surgery with or without primary posterior continuous curvilinear capsulorrhexis: an intra-individual randomized controlled trial

PURPOSE

To evaluate the effect of primary posterior continuous curvilinear capsulorrhexis (PPCCC) on the positional stability of IOLs.

METHODS

This study is a prospective intra-individual comparative randomized controlled trial including 31 patients (62 eyes). Eyes of the same patient were randomly assigned to the PPCCC group (18 right eyes and 13 left eyes) or group without PPCCC (NPCCC group). Eyes in both groups were implanted with a one-piece foldable hydrophobic acrylic IOL via routine cataract surgery. Patients in the PPCCC group underwent additional manual PPCCC before IOL implantation. Examinations were performed 1 day, 1 week, 1 month and 3 months postoperatively. IOL tilt (x, y), decentration (x, y), anterior chamber depth (z) and refractive prediction error data were collected and analyzed with Pentacam.

RESULTS

Postoperatively, the range of IOL position change over 3 months in PPCCC group was comparable to NPCCC group, which indicated smaller value in every tilt and decentration index. PPCCC eyes showed comparable tilt and decentration with NPCCC eyes in this study endpoint: mean tilt (x, y), decentration (x, y) and anterior chamber depth (ACD) were 1.04 ± 0.56°, 0.90 ± 0.64°, 0.239 ± 0.140 mm, 0.233 ± 0.133 mm and 4.01 ± 0.32 mm, respectively, in the PPCCC group vs. 1.09 ± 0.76°, 1.10 ± 0.82°, 0.252 ± 0.153 mm, 0.244 ± 0.155 mm and 4.01 ± 0.38 mm, respectively, in the NPCCC group. Refractive prediction error in the PPCCC group demonstrated a mild hyperopic shift vs. the NPCCC group (0.13 ± 0.50 vs. 0.05 ± 0.39; p = 0.208), and corrected distance visual acuity (CDVA) did not differ between the two groups (0.027 ± 0.014 vs. 0.059 ± 0.185; p = 0.377).

CONCLUSIONS

Comparable IOL tilt, decentration, ACD and refractive prediction error were observed in PPCCC eyes with that underwent routine cataract surgery. Little IOL position fluctuation and good visual acuity were shown in PPCCC group over time.

TRAIL REGISTRATION

The study was registered at the Chinese Clinical Trial Register Center on May 27th, 2020 (protocol code ChiCTR2000033304, 27/05/2020).

Current State of the Art and Next Generation of Materials for a Customized IntraOcular Lens according to a Patient-Specific Eye Power

Intraocular lenses (IOLs) are commonly implanted after surgical removal of a cataractous lens. A variety of IOL materials are currently available, including collamer, hydrophobic acrylic, hydrophilic acrylic, PHEMA copolymer, polymethylmethacrylate (PMMA), and silicone. High-quality polymers with distinct physical and optical properties for IOL manufacturing and in line with the highest quality standards on the market have evolved to encompass medical needs. Each of them and their packaging show unique advantages and disadvantages. Here, we highlight the evolution of polymeric materials and mainly the current state of the art of the unique properties of some polymeric systems used for IOL design, identifying current limitations for future improvements. We investigate the characteristics of the next generation of IOL materials, which must satisfy biocompatibility requirements and have tuneable refractive index to create patient-specific eye power, preventing formation of posterior capsular opacification.

Camellens FIL622-1 IOL Implantation in the Ciliary Sulcus: Refractive Outcomes and Optimization of A-constant

PURPOSE

To assess the refractive outcomes of patients who had sulcus implantation of the Camellens FIL622-1 intraocular lens (IOL) (Soleko) after posterior capsular rupture, and to optimize the A-constant suggested by the manufacturer.

METHODS

This study included patients who underwent secondary Camellens FIL622-1 IOL implantation in the ciliary sulcus after complicated cataract surgery with posterior capsular rupture. IOL power was calculated by the SRK/T formula, using the recommended A-constant (118.8) for ciliary sulcus implantation. A new optimized A-constant was obtained and used to evaluate the refractive outcomes. The main outcome measures were mean prediction error (PE), median absolute error (MedAE), mean absolute error (MAE), and percentage of eyes with a PE within ±0.50, ±1.00, and ±2.00 diopters (D).

RESULTS

Forty patients (40 eyes) were included in the study. The new optimized A-constant was 117.5, and the mean PE, MedAE, and MAE was -0.02 ± 0.73, 0.34, and 0.54, respectively. The percentage of eyes with a PE within ±0.50, ±1.00, and ±2.00 D was 65%, 87.5%, and 100%, respectively.

CONCLUSIONS

The Camellens FIL622-1 IOL represents a valid option as sulcus implantation after posterior capsular rupture and it would guarantee the surgeon an on-label option with a more accurate biometric calculation, at the time of surgical implantation, with the new optimized A-constant. [J Refract Surg. 2022;38(12):806-811.].

Predicting Residual Astigmatism in Cataract Surgery

The purpose of this review is to evaluate the prediction of postoperative residual astigmatism and to determine the best prediction method for astigmatism correction. In recent findings for residual astigmatism in non-toric monofocal intraocular lens (IOL) implanted eyes, vector analysis can be used to correctly evaluate residual astigmatism by decomposing it. In predicting residual astigmatism, the with-the-rule (WTR) and against-the-rule (ATR) astigmatism components can now be almost predicted. This may be due to advances in inspection equipment and surgical technique. However, there are still issues with the oblique astigmatism component. In addition, corneal astigmatism is the most important predictor of postoperative residual astigmatism, and other predictors, such as refractive astigmatism, age, and lens thickness, have also been mentioned. However, all but corneal astigmatism are questionable because of the possibility of confounding variables. Total corneal astigmatism is more accurate in predicting residual astigmatism than anterior corneal astigmatism. Several predictions of residual astigmatism have been reported, but complete prediction has not been possible. Further research is needed, especially in predicting oblique astigmatism. However, I emphasize that the accuracy of predicting WTR and ATR astigmatism has improved considerably and can be predicted using regression equations with total corneal astigmatism.

Rotational Stability of a New Hydrophobic Acrylic IOL With Modified C-loop Haptics

PURPOSE

To assess rotational stability, axial stability, decentration, and tilt of the Rayner RAO800C single-piece hydrophobic acrylic intraocular lens (IOL) (Rayner Intraocular Lenses Ltd) from end of surgery to 4 to 7 months postoperatively.

METHODS

Surgeries were performed at the Department of Ophthalmology at the Medical University of Vienna. A total of 130 eyes of 68 patients received an aspheric hydrophobic Rayner RAO0800C IOL. IOLs were randomly implanted to the 0 ± 10, 45 ± 10, 90 ± 10, or 135 ± 10 degree axis. Baseline measurement was performed with the patient still supine on the operating table. Axis alignment after 1 hour, 1 week, 1 month, and 4 months was evaluated by retroillumination pictures. Postoperative IOL decentration, tilt, and aqueous depth at 4 months were assessed using an anterior segment swept-source optical coherence tomography.

RESULTS

Absolute median IOL rotation from end of surgery to 4 months was 2.4 degrees (range: 0.0 to 85.0 degrees). Median IOL rotation from end of surgery to 1 hour, 1 hour to 1 week, 1 week to 1 month, and 1 month to 4 months was 1.6 (range: 0.0 to 86.2), 1.1 (range: 0.0 to 28.8), 0.6 (range: 0.0 to 5.2), and 0.7 (range: 0.0 to 2.6) degrees. Respective proportions of IOLs rotating more than 5, 10, and 20 degrees from end of surgery to 4 months were 23.9%, 11.0%, and 6.4%. Horizontal and vertical decentration at 4 months was -0.09 ± 0.14 and 0.09 ± 0.14 mm, respectively. Horizontal and vertical tilt at 4 months was -4.78 ± 1.36 and -1.58 ± 1.10 degrees, respectively. A posterior axial shift of 0.052 ± 0.055 mm was observed from 1 week to 4 months.

CONCLUSIONS

Although median IOL rotation appeared to be low, a significant proportion of IOLs rotated postoperatively. Decentration and tilt values were generally low. A minimal posterior optic shift was observed after 1 week. [J Refract Surg. 2021;37(2):112-118.].

Characteristics and factors associated with intraocular lens tilt and decentration after cataract surgery

PURPOSE

To analyze the characteristics and factors associated with intraocular lens (IOL) tilt and decentration after uneventful phacoemulsification with IOL implantation.

SETTING

Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.

DESIGN

Cross-sectional study.

METHODS

All patients underwent a general ophthalmologic examination and anterior segment photography. IOL tilt and decentration were measured with a second-generation anterior segment optical coherence tomography (Casia2). Univariate and multivariate regression analyses were performed to assess the association between IOL tilt and decentration with ocular biometric and systemic parameters, and the visual acuity.

RESULTS

A total of 196 eyes of 196 patients were enrolled in this study. IOLs showed a mean tilt of 4.8 degrees toward the inferotemporal direction, and the mean decentration was 0.21 mm. Both eyes presented a mirror symmetry relationship. Twenty-two eyes (11.22%) had a tilt greater than 7 degrees, and 21 eyes (10.72%) had a decentration more than 0.4 mm. Multivariate regression analysis showed previous pars plana vitrectomy (PPV) and short axial length (AL) were associated with greater IOL tilt (P = .014 and P < .001). In addition, long AL, thicker lens, and less capsulorhexis-IOL overlap were positively correlated with decentration (P < .001, P = .029, and P = .026). Corrected distance visual acuity did not directly correlate with IOL tilt and decentration (P = .417 and P = .550).

CONCLUSIONS

PPV history and short AL were associated with greater IOL tilt, whereas longer AL, thicker lens, and overlarge capsulorhexis contribute to greater decentration. Implantation of toric and multifocal IOLs in these patients should be cautious.

The Aravind Pseudoexfoliation Study: 5-Year Postoperative Results. The Effect of Intraocular Lens Choice and Capsular Tension Rings

PURPOSE

We compared rates of intraocular lens (IOL) decentration, neodymium-doped yttrium aluminum garnet capsulotomy for posterior capsule opacification (PCO), and visual acuity (VA) in eyes with and without pseudoexfoliation (PEX) 5 years after undergoing cataract surgery.

DESIGN

Prospective comparative interventional study.

METHODS

This multicenter study population included 1 eye of both 930 cataract patients with and 470 cataract patients without uncomplicated PEX (no small pupils or phacodonesis) all undergoing phacoemulsification by experienced Aravind Eye Care System surgeons. Eyes were randomized to either 1- or 3-piece intraocular lenses (IOLs). PEX eyes were also randomized to either receive or not receive a capsule tension ring. The main outcome measures included IOL decentration and PCO. Secondary outcomes included postoperative best-corrected VA.

RESULTS

Follow-up was 86.2% in the PEX group and 86.7% in the control group at 5 years. The PEX group was older (P < .001) and had more men (P = .01). IOL decentration at 5 years was equally prevalent in PEX and control eyes (1.0% vs 1.1%, respectively, P = .8). Neodymium-doped yttrium aluminum garnet posterior capsulotomy rates for PCO were similar in the PEX group when compared with control subejcts (5.3% compared with 3.2%, respectively, P = .07). Best corrected VA was better at baseline and years 2 and 3 in the control group (P = .0001, P = .0005, and P = .02); however, there was no difference in BCVA at years 1, 4, and 5 between the PEX and control groups (P = .09, P = .29, and P = .5).

CONCLUSION

In a large-scale, long-term, prospective comparative study of cataract surgery in eyes with uncomplicated PEX, the risks of IOL decentration and PCO were low and comparable to that in control subjects. When approaching cataract surgery in eyes with relatively uncomplicated PEX, neither IOL choice (1- vs 3-piece acrylic IOL) nor the presence/absence of a capsule tension ring affects outcomes at 5 years.

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

Tilt and decentration of intraocular lenses (IOL) may occur secondary to a complicated cataract surgery or following an uneventful phacoemulsification. Although up to 2–3° tilt and a 0.2–0.3 mm decentration are common and clinically unnoticed for any design of IOL, larger extent of tilt and decentration has a negative impact on the optical performance and subsequently, the patients’ satisfaction. This negative impact does not affect various types of IOLs equally. In this paper we review the methods of measuring IOL tilt and decentration and focus on the effect of IOL tilt and decentration on visual function, in particular visual acuity, dysphotopsia, and wavefront aberrations. Our review found that the methods to measure the IOL displacement have significantly evolved and the available studies have employed different methods in their measurement, while comparability of these methods is questionable. There has been no universal reference point and axis to measure the IOL displacement between different studies. A remarkably high variety and brands of IOLs are used in various studies and occasionally, opposite results are noticed when two different brands of a same design were compared against another IOL design in two studies. We conclude that <5° of inferotemporal tilt is common in both crystalline lenses and IOLs with a correlation between pre- and postoperative lens tilt. IOL tilt has been noticed more frequently with scleral fixated compared with in-the-bag IOLs. IOL decentration has a greater impact than tilt on reduction of visual acuity. There was no correlation between IOL tilt and decentration and dysphotopsia. The advantages of aspheric IOLs are lost when decentration is >0.5 mm. The effect of IOL displacement on visual function is more pronounced in aberration correcting IOLs compared to spherical and standard non-aberration correcting aspherical IOLs and in multifocal versus monofocal IOLs. Internal coma has been frequently associated with IOL tilt and decentration, and this increases with pupil size. There is no correlation between spherical aberration and IOL tilt or decentration. Although IOL tilt produces significant impact on visual outcome in toric IOLs, these lenses are more sensitive to rotation compared to tilt.

Biomechanical Stability of Three Intraocular Lenses With Different Haptic Designs: In Silico and In Vivo Evaluation

PURPOSE

To assess the biomechanical stability of three different marketed intraocular lenses (IOLs) with different haptic designs (four-loop IOL [Micro F FineVision model] and double C-loop IOL [POD F and POD FT models], all manufactured by PhysIOL), in silico (computer simulation) and in vivo (in the context of lens surgery).

METHODS

An in silico simulation investigation was performed using finite element modeling (FEM) software to reproduce the compression test defined by the International Organization for Standardization and in vivo implantation in patients in the context of lens surgery was evaluated 1 day and 3 months postoperatively. IOL decentration and rotation were tested. In addition, the stress and strains were analyzed with the finite element method.

RESULTS

In the in silico evaluation, the compression force for the POD F IOL was slightly lower than for the POD FT IOL and Micro F IOL for all compression diameters. The axial displacement was maximum for the POD FT IOL and the tilt, rotation, and lateral decentration were substantially lower than the acceptable tolerance limits established in ISO 11979-2. In the in vivo evaluation, a total of 45 eyes from 45 patients were selected, 15 eyes for each IOL model under assessment. Statistically significant differences were found between the Micro F and POD F IOLs for lateral decentration in x-direction (in absolute value) at 3 months postoperatively (P = .03).

CONCLUSIONS

Although statistically significant differences have been found when comparing the displacement, tilt, and rotation between the different lenses, these differences cannot be considered clinically relevant, which would suggest that all three IOL models yield excellent stability in those terms. FEM appears to be a powerful tool for numerical studies of the biomechanical properties of IOLs. [J Refract Surg. 2020;36(9):617-624.].

Impact of vitrectomy and air tamponade on aspheric intraocular lens tilt and decentration and ocular higher-order aberrations: phacovitrectomy versus cataract surgery

PURPOSE

To evaluate the impact of vitrectomy and air tamponade on aspheric intraocular lens (IOL) tilt and decentration and postoperative internal higher-order aberrations (HOAs) in combined cataract surgery and vitrectomy (phacovitrectomy).

STUDY DESIGN

Prospective comparative observational study.

METHODS

Forty-five eyes that underwent phacovitrectomy using aspheric IOLs and 18 eyes that only underwent cataract surgery also using aspheric IOLs were prospectively evaluated. The subjects were divided into three groups: phacovitrectomy without fluid-air exchange (F/Ax) or with F/Ax and cataract surgery alone (Groups A, B, and C, respectively) Surgery-induced changes in lens tilt and decentration and internal HOAs were compared between each pair of groups. Subgroup analysis was conducted for cases with largely tilted (> 7°) or decentered (> 0.40 mm) IOLs 1 month postoperatively.

RESULTS

Surgery-induced changes in lens tilt in Group B were significantly more pronounced than those in Group C at 1 week, 1 month, and 3 months postoperatively (P = 0.007, 0.009, and 0.043, respectively), while there was no significant difference in surgery-induced changes in lens decentration among the groups. IOLs in Group B were tilted and decentered toward the inferonasal direction. In contrast, there was no significant difference in internal HOAs among the groups at any postoperative visit. Only Group B included cases with largely decentered IOLs, and the internal total HOAs in these cases were significantly larger than those in the others (P = 0.015).

CONCLUSION

Although largely decentered IOLs were occasionally found in Group B, aspheric IOLs could be effectively used in phacovitrectomy.

Anterior chamber depth - a predictor of refractive outcomes after age-related cataract surgery

Background

Anterior chamber depth (ACD) is becoming a hot topic and plays an important role in correcting the refractive errors (REs) after cataract surgery. The aim of this study was to assess the ACD changes and their relationship with the REs after phacoemulsification and intraocular lens (IOL) implantation in patients with age-related cataracts.

Methods

One hundred forty-five eyes of 125 age-related cataract patients from the Department of Ophthalmology, Tangdu Hospital, China, were recruited. IOL Master was used for axial length (AL) and the IOL power calculation measurements, and the Pentacam HR device was used for the ACD and lens thickness (LT) measurements. Every patient underwent uncomplicated phacoemulsification by a single surgeon using a single technique. Postoperative refraction results were obtained at 1 month. The appropriate formula used for the IOL power calculation was chosen depending on the AL, specifically the Hoffer Q (AL < 22.0 mm), SRK/T (22.0 mm ≤ AL ≤ 30.0 mm), and Haigis (AL > 30.0 mm) formulas.

Results

The postoperative ACD was deepened and tended to stabilize gradually after 2 weeks. A concurrent hyperopic shift (0.57 ± 0.47 D) was observed when the change in the ACD was less than 1.65 mm, whereas a myopic shift (− 0.18 ± 0.62 D) occurred contrarily, and the difference between the two groups was statistically significant (P < 0.0001). The change in ACD was significantly larger in the shallow anterior chamber (1.92 ± 0.40 mm) than in the deep chamber (1.33 ± 0.42 mm) (P < 0.0001). Similarly, the change in ACD was larger in the short AL (2.12 ± 0.37 mm) than in the long AL (1.32 ± 0.49 mm). The postoperative ACD and refractive changes were correlated with the preoperative ACD and AL (P < 0.0001), respectively. Two regression formulas were proposed: postoperative ACD = 3.524 + 0.294 × preoperative ACD and postoperative ACD = 3.361 + 0.228× (preoperative ACD + 1/2 LT).

Conclusions

The results of this study showed that the ACD deepened and was associated with a concurrent RE after cataract surgery. Postoperative changes in the ACD were related to the preoperative ACD and AL, which determined the refraction status and visual quality. The regression formula of the postoperative ACD could provide a theoretical basis for predicting refractive errors in the clinic.

Haptic fracture and dislocation of polyimide intraocular lens after neodymium: YAG laser capsulotomy: A case report

RATIONALE

We report a case of haptic fracture of polyimide intraocular lens (IOL) and its dislocation after neodymium:YAG (Nd:YAG) laser capsulotomy. To the best of our knowledge, this is the first report of both the fracture and dislocation of the IOL after laser posterior capsulotomy.

PATIENT CONCERNS

A 78-year-old male was referred to our clinic with a history of decreased visual acuity after Nd:YAG laser posterior capsulotomy in the right eye. A dislocated IOL was observed on slit lamp examination.

DIAGNOSIS

On slit-lamp examination, dislocated IOL with intact anterior capsulorrhexis margin was observed in the right eye.

INTERVENTIONS

We removed the dislocated IOL and fixed a 3-piece IOL (Acrysof MN60AC, Alcon Laboratories, Inc) in the ciliary sulcus under retrobulbar anesthesia.

OUTCOMES

After the operation, the observed uncorrected distance visual acuity (UCVA) was 20/20 and the measured intraocular pressure (IOP) was 18 mmHg; the IOL was fixed in the ciliary sulcus.

LESSONS

Three-piece, silicone-polyimide haptics in IOLs can get fractured after Nd:YAG laser capsulotomy. Thus, it is suggested that sufficient haptic dilation should be ensured while performing Nd:YAG laser capsulotomy in patients with polyimide haptics. Moreover, a small-sized capsulotomy is likely to be helpful in such patients.

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.

Influence of material and haptic design on the mechanical stability of intraocular lenses by means of finite-element modeling

Intraocular lenses (IOLs) are used in the cataract treatment for surgical replacement of the opacified crystalline lens. Before being implanted they have to pass the strict quality control to guarantee a good biomechanical stability inside the capsular bag, avoiding the rotation, and to provide a good optical quality. The goal of this study was to investigate the influence of the material and haptic design on the behavior of the IOLs under dynamic compression condition. For this purpose, the strain-stress characteristics of the hydrophobic and hydrophilic materials were estimated experimentally. Next, these data were used as the input for a finite-element model (FEM) to analyze the stability of different IOL haptic designs, according to the procedure described by the ISO standards. Finally, the simulations of the effect of IOL tilt and decentration on the optical performance were performed in an eye model using a ray-tracing software. The results suggest the major importance of the haptic design rather than the material on the postoperative behavior of an IOL. FEM appears to be a powerful tool for numerical studies of the biomechanical properties of IOLs and it allows one to help in the design phase to the manufacturers.