Intraocular Lens Power, Myopia, and the Risk of Nd:YAG Capsulotomy after 15,375 Cataract Surgeries

Recurrent Posterior Capsular Opacification in Adults: A Case Report and an Overview of Literature

Posterior capsular opacification (PCO), also known as "secondary cataract", is a common complication following cataract surgery that can significantly impair visual acuity. The incidence of PCO varies widely in the literature, influenced by intraocular lens (IOL) type and patient risk factors. Neodymium-doped yttrium-aluminum-garnet (YAG) laser posterior capsulotomy is the standard treatment for PCO-related visual impairment. Recurrence of PCO after initial treatment with YAG capsulotomy, though more common in children, is rare in adults. Its underlying pathophysiological mechanisms are similar to that of primary PCO, which includes proliferation, migration, and/or clustering of lens epithelial cells (LECs), with subsequent reclosure of the posterior aperture. Potential risk factors for PCO recurrence that have been speculated through a comprehensive search of the current literature include younger age, female sex, high myopia, diabetes, vitrectomized status, uveitis, low-diopter IOLs, and certain IOL types with higher water content. We present a case of recurrent PCO in a highly myopic 48-year-old male following cataract surgery and implantable collamer lens (ICL) explantation who received a hydrophobic acrylic lens with 4% water content. Surgical techniques that may reduce recurrent PCO occurrence and appropriate postoperative care are emphasized to assist surgeons in their approach to patients at high-risk for this complication.

Safety and efficacy of capsular tension ring and capsular hook implantation for managing ectopia lentis in Marfan syndrome: real-world study

PURPOSE

To evaluate the safety and efficacy of capsular tension ring and capsular hook (CTR-CH) implantation in Marfan syndrome (MFS) patients with ectopia lentis (EL).

SETTING

Eye and ENT Hospital of Fudan University, Shanghai, China.

DESIGN

Retrospective propensity score-matched cohort study.

METHODS

This study included patients with MFS who had in-the-bag intraocular lens (IOL) implantation assisted by CTR-CH or modified CTR (MCTR). The safety analysis focused on the resurgery rate. The efficacy analysis compared the corrected distance visual acuity (CDVA) and the incidence of laser capsulotomy after propensity score matching (PSM).

RESULTS

This study encompassed 148 eyes that had the CTR-CH procedure and 162 eyes that received MCTR implantation. In the CTR-CH group, the median age at the time of surgery was 5 years, with a mean follow-up duration of 1.81 ± 0.4 years. 5 eyes (3.38%) required a second surgery because of retinal detachment (2, 1.35%), IOL decentration (2, 1.35%), and CH dislocation (1, 0.68%). The resurgery rate was comparable with that of the MCTR group ( P = .486). After PSM, a total of 108 eyes were recruited in each group. Postoperative CDVA was significantly improved in both groups (both P < .001), but comparable between the groups ( P = .057). The posterior capsular opacification took place earlier ( P = .046) while the anterior capsular opacification required laser capsulotomy at a later stage ( P = .037) compared with the MCTR group.

CONCLUSIONS

The CTR-CH procedure was a feasible, safe, and efficient approach for managing EL in patients with MFS.

Challenges of refractive cataract surgery in the era of myopia epidemic: a mini-review

Myopia is the leading cause of visual impairment in the world. With ever-increasing prevalence in these years, it creates an alarming global epidemic. In addition to the difficulty in seeing distant objects, myopia also increases the risk of cataract and advances its onset, greatly affecting the productivity of myopes of working age. Cataract management in myopic eyes, especially highly myopic eyes is originally more complicated than that in normal eyes, whereas the growing population of cataract with myopia, increasing popularity of corneal and lens based refractive surgery, and rising demand for spectacle independence after cataract surgery all further pose unprecedented challenges to ophthalmologists. Previous history of corneal refractive surgery and existence of implantable collamer lens will both affect the accuracy of biometry including measurement of corneal curvature and axial length before cataract surgery, which may result in larger intraocular lens (IOL) power prediction errors and a compromise in the surgical outcome especially in a refractive cataract surgery. A prudent choice of formula for cataract patients with different characteristics is essential in improving this condition. Besides, the characteristics of myopic eyes might affect the long-term stability of IOL, which is important for the maintenance of visual outcomes especially after the implantation of premium IOLs, thus a proper selection of IOL accordingly is crucial. In this mini-review, we provide an overview of the impact of myopia epidemic on treatment for cataract and to discuss new challenges that surgeons may encounter in the foreseeable future when planning refractive cataract surgery for myopic patients.

Long-Term Outcomes of Posterior Capsular Opacification in Highly Myopic Eyes and Its Influencing Factors

INTRODUCTION

The purpose of this study was to evaluate the long-term outcomes of posterior capsular opacification (PCO) in highly myopic eyes and its influencing factors.

METHODS

Patients undergoing phacoemulsification with intraocular lens implantation and followed up for 1-5 years were included in this prospective cohort study. The severity of PCO was evaluated using EPCO2000 software system, with the area of central 3.0 mm (PCO-3 mm) and within the capsulorhexis (PCO-C) both being analyzed. Percentage of eyes after Nd:YAG capsulotomy, as well as clinically significant PCO (defined as eyes with visual-impairing PCO or after capsulotomy), were also included as outcome variables.

RESULTS

A total of 673 highly myopic eyes [axial length (AL) ≥ 26 mm] and 224 control eyes (AL < 26 mm) were analyzed. The mean follow-up time was 34.0 ± 9.0 months. PCO was more severe in highly myopic eyes compared with controls with regard to higher EPCO scores (P < 0.001 for both PCO-3 mm and PCO-C), higher capsulotomy rate (P = 0.001), higher clinically significant PCO rate (P < 0.001) and shorter PCO-free survival time (P < 0.001). Extreme myopia (AL ≥ 28 mm) would further aggravate PCO in terms of higher EPCO scores (PCO-3 mm: P = 0.017; PCO-C: P = 0.013) and higher clinically significant PCO rate (P = 0.024) compared with other myopic eyes. In highly myopic eyes, AL [odds ratio (OR) 1.124, P = 0.004] and follow-up duration (OR 1.082, P < 0.001) were independent risk factors for clinically significant PCO after cataract surgery.

CONCLUSION

Highly myopic eyes had more severe PCO in the long term. Longer AL and follow-up duration were associated with higher risk of PCO.

CLINICAL TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (NCT03062085).

Advancements in Postoperative Care after Cataract Surgery

Cataract surgery is one of the most frequently performed surgical procedures in many countries [...].

Prior pars plana vitrectomy and its association with adverse intraoperative events during cataract surgery

PURPOSE

To evaluate the risk of intraoperative complications during cataract surgery in eyes with a prior vitrectomy.

METHODS

A retrospective review of data from our cataract surgery registry of all patients undergoing cataract surgery between 2014 and 2018 at the University of Colorado Hospital. Univariate and multivariate analyses were conducted, accounting for intra-patient correlation in subjects who underwent two cataract surgeries. The three main outcomes of interest, zonulopathy, posterior capsule (PC) tears and dropped lens fragments, were analysed for their association with prior pars plana vitrectomy (PPV) and clinical characteristics of patients such as history of prior intravitreal injection and surgeon level of experience.

RESULTS

10 540 eyes of 6447 patients were included in the analysis. 371 (3.5%) eyes had a prior PPV. Eyes with a prior PPV experienced more zonulopathy during cataract surgery (adjusted OR 2.2, 95% confidence interval: 1.3-3.7, p = 0.002). Combined phacoemulsification/PPV were significantly more likely to experience all 3 complications, and this effect was even greater for eyes with a prior PPV.

CONCLUSIONS

All complications were rare; however, there was a significant association with prior PPV and intraoperative zonulopathy. Cataract surgeons must be aware of a patient's prior vitrectomy and plan accordingly for the increased risk of intraoperative complications.

αVβ8 integrin targeting to prevent posterior capsular opacification

Fibrotic posterior capsular opacification (PCO), a major complication of cataract surgery, is driven by transforming growth factor–β (TGF-β). Previously, αV integrins were found to be critical for the onset of TGF-β–mediated PCO in vivo; however, the functional heterodimer was unknown. Here, β8 integrin–conditional knockout (β8ITG-cKO) lens epithelial cells (LCs) attenuated their fibrotic responses, while both β5 and β6 integrin–null LCs underwent fibrotic changes similar to WT at 5 days post cataract surgery (PCS). RNA-Seq revealed that β8ITG-cKO LCs attenuated their upregulation of integrins and their ligands, as well as known targets of TGF-β–induced signaling, at 24 hours PCS. Treatment of β8ITG-cKO eyes with active TGF-β1 at the time of surgery rescued the fibrotic response. Treatment of WT mice with an anti-αVβ8 integrin function blocking antibody at the time of surgery ameliorated both canonical TGF-β signaling and LC fibrotic response PCS, and treatment at 5 days PCS, after surgically induced fibrotic responses were established, largely reversed this fibrotic response. These data suggest that αVβ8 integrin is a major regulator of TGF-β activation by LCs PCS and that therapeutics targeting αVβ8 integrin could be effective for fibrotic PCO prevention and treatment.

The Protective Effect of Metformin Use on Early Nd:YAG Laser Capsulotomy

Purpose

To determine the effect of metformin on early Nd:YAG laser treatment for posterior capsule opacification (PCO) and to explore a molecular mechanism to explain a possible protective effect of metformin against PCO.

Methods

We conducted: 1) a retrospective cohort study of patient eyes undergoing phacoemulsification at our institution; and 2) laboratory investigation of the effect of metformin on the behavior of lens epithelial cells in the context of an animal model for PCO. Population-averaged Cox proportional hazards modeling was used to estimate risk for time to Nd:YAG. For laboratory studies, expression of markers for epithelial-to-mesenchymal transition (EMT) implicated in PCO pathogenesis was measured in tissue culture and following extracapsular lens extraction in a mouse model.

Results

The rate of Nd:YAG laser capsulotomy was 13.1% among the 9798 eyes. Both metformin use and diabetes were protective factors for Nd:YAG laser capsulotomy in univariate analysis. However, in multivariable analysis with nondiabetics as the reference group, only metformin use among diabetics was significantly protective of Nd:YAG (hazard ratio: 0.68, 95% CI: 0.54–0.85, P = 0.0008), while eyes of patients with diabetes without metformin use did not significantly differ (P = 0.5026). Treatment of lens epithelial cells with metformin reduced the level of the EMT markers ⍺-SMA and pERK induced by TGF-β2. Similarly, metformin treatment reduced ⍺-SMA expression in lens epithelial cells following extracapsular lens extraction in a mouse model.

Conclusions

The protective effect of metformin against early Nd:YAG may relate to its ability to downregulate EMT in residual lens epithelial cells that otherwise trend toward myofibroblast development and PCO.

The aging mouse lens transcriptome

Age is a major risk factor for cataract (ARC). However, the influence of aging on the lens transcriptome is under studied. Lens epithelial (LEC) and fiber cells (LFC) were isolated from young (3 month old) and aged (24 month old) C57BL/6J mice, and the transcriptome elucidated via RNAseq. EdgeR estimated differential gene expression in pairwise contrasts, and Advaita's Ipathway guide and custom R scripts were used to evaluate the potential biological significance of differentially expressed genes (DEGs). This analysis revealed age-dependent decreases in lens differentiation marker expression in both LECs and LFCs, with gamma crystallin transcripts downregulating nearly 50 fold in aged LFCs. The expression of the transcription factors Hsf4 and Maf, which are known to activate lens fiber cell preferred genes, are downregulated, while FoxE3, which represses gamma crystallin expression, is upregulated in aged fibers. Aged LECs upregulate genes controlling the immune response, complement pathways, and cellular stress responses, including glutathione peroxidase 3 (Gpx3). Aged LFCs exhibit broad changes in the expression of genes regulating cell communication, and upregulate genes involved in antigen processing/presentation and cholesterol metabolism, while changes in the expression of mitochondrial respiratory chain genes are consistent with mitochondrial stress, including upregulation of NDufa4l2, which encodes an alternate electron transport chain protein. However, age did not profoundly affect the response of LECs to injury as both young and aged LECs upregulate inflammatory gene signatures at 24 h post injury to similar extents. These RNAseq profiles provide a rich data set that can be mined to understand the genetic regulation of lens aging and how this impinges on the pathophysiology of age related cataract.