Factors Associated with the Development of Posterior Capsule Opacification Requiring Yttrium Aluminum Garnet Capsulotomy

Unintended placement of intraocular lens haptics in the sulcus and its association with posterior capsular opacification in pseudophakic post-mortem eyes

OBJECTIVE

To assess the prevalence of unintended placement of intraocular lens (IOL) haptics in the sulcus and its association with posterior capsular opacification (PCO).

DESIGN

Cross-sectional study.

PARTICIPANTS

428 post-mortem pseudophakic human eyes.

METHODS

Eyes were obtained from the Lions Gift of Sight and imaged in Miyake-Apple view (MAV). IOL haptic placement (bag-bag, bag-sulcus, sulcus-sulcus) was determined from the MAV images. IOL-capsular bag complexes were extracted and analyzed via Automated Detector Opacification Software to quantify PCO and Soemmering's Ring (SR). SR distribution was categorized as focal, diffuse, or none. Mean differences in PCO and SR between haptic groups were assessed via Welch's t-test. Odds ratios were used to compare the risk of SR distribution patterns between both haptic groups. Sex, clinical history (diabetes, smoking, hypertension, glaucoma, cancer, age-related macular degeneration [AMD], hypercholesterolemia, cardiovascular disease), and IOL model and specifications were collected.

RESULTS

20 eyes (4.67%) had unintended sulcus placement of haptics. Mean PCO (p = 0.0367) and SR (p = 0.0414) were significantly higher in sulcus eyes. Sulcus eyes were significantly more at risk of focal SR distribution (OR 8.715; p < 0.0001) and significantly less at risk of diffuse SR distribution (OR 0.168; p = .0007). Sulcus eyes had significantly higher frequencies of glaucoma (p < 0.0001) and AMD (p = 0.0023) on clinical history.

CONCLUSIONS

This study demonstrates that unintended sulcus placement of IOL haptics may be associated with an increased risk of PCO and SR formation. This study offers clinical signs of sulcus haptic placement that may prompt physicians to seek earlier appropriate intervention.

How do intraocular lens materials influence the outcome of cataract surgery?

PURPOSE OF REVIEW

This review summarizes the evidence on the effect of intraocular lens (IOL) material on the outcomes of cataract surgery, as well as on the surgical procedure itself.

RECENT FINDINGS

Differences in capsular biocompatibility between IOL materials lead to variations in capsular stability and posterior capsule opacification (PCO), while differences in uveal biocompatibility affect postoperative inflammatory response.

SUMMARY

Refractive outcomes are affected by both incision size and the rotational stability of toric IOLs. Small incision sizes favour hydrophilic IOLs. Rotational stability of hydrophobic and hydrophilic IOLs were comparable in recent studies. Visual outcomes are affected by chromatic aberrations, dysphotopsia, lens opacifications and PCO. Hydrophilic IOLs are associated with reduced chromatic dispersion. Hydrophobic IOL opacifications are caused by sub-surface glistenings, while hydrophilic IOL opacifications are due to surface calcifications. Some surgeries, including pars plana vitrectomy and lamellar corneal transplants, were shown to increase the risk of IOL calcifications, although the mechanism is still unknown. Hydrophilic IOLs have greater ease of manipulation, greater resistance to IOL damage, and higher uveal biocompatibility. Hydrophobic IOLs show better PCO prevention than hydrophilic IOLs, and should be preferred in highly myopic eyes where Nd:YAG capsulotomy might increase the risk of retinal detachment.

Oxidative Stress, Glutaredoxins, and Their Therapeutic Potential in Posterior Capsular Opacification

Posterior capsular opacification (PCO) is the most common long-term complication of cataract surgery. Traditionally, the pathogenesis of PCO involves the residual lens epithelial cells (LECs), which undergo transdifferentiation into a myofibroblast phenotype, hyperproliferation, matrix contraction, and matrix deposition. This process is driven by the marked upregulation of inflammatory and growth factors post-surgery. Recently, research on the role of redox environments has gained considerable attention. LECs, which are in direct contact with the aqueous humour after cataract surgery, are subjected to oxidative stress due to decreased levels of reduced glutathione and increased oxygen content compared to contact with the outer fibre layer of the lens before surgery. In this review, we examine the critical role of oxidative stress in PCO formation. We also focus on glutaredoxins (Grxs), which are antioxidative enzymes produced via deglutathionylation, their protective role against PCO formation, and their therapeutic potential. Furthermore, we discuss the latest advancements in PCO therapy, particularly the development of advanced antioxidative pharmacological agents, and emphasise the importance and approaches of anti-inflammatory and antioxidant treatments in PCO management. In conclusion, this review highlights the significant roles of oxidative stress in PCO, the protective effects of Grxs against PCO formation, and the potential of anti-inflammatory and antioxidant therapies in treating PCO.

Comparison of the outcomes of phacoemulsification versus topical medication alone in canine diabetic cataracts: a retrospective study

BACKGROUND

Long-term comparisons of phacoemulsification with topical medication are limited in canine diabetic cataracts.

OBJECTIVES

To compare outcomes of eyes submitted to phacoemulsification with those of topical medication for canine diabetic cataracts and identify risk factors for complications.

METHODS

Through medical records review, 150 eyes (76 dogs) with diabetic cataracts were included; 58 eyes (31 dogs) underwent phacoemulsification (phaco-group) and 92 eyes (48 dogs) received ophthalmic solution alone (medication-group). The medication-group was divided into owner-led and vet-led groups depending on who elected not to perform surgery. Comparisons involved time-to-complications, vision, and the number and type of ophthalmic solutions administered. The association between complications and pretreatment clinical findings was investigated.

RESULTS

No difference was found in complication risk between the phaco and owner-led medication groups. Conversely, the vet-led medication-group had a higher complication risk than the other groups. At the last follow-up, 94.8% of the phaco-group had vision, whereas 7.6% of the medication-group restored some visual axis. Poor glycemic control in the medication-group and younger age in the phaco-group increased complication risk. At 1-year post-treatment, the average number of ophthalmic solutions administered was 1.7 and 2.6 in the phaco and medication groups, respectively. The medication-group used anti-inflammatories the most throughout the follow-up, whereas the phaco-group used anti-inflammatories the most until 1-year post-treatment and lacrimostimulants at 1.5-year post-treatment.

CONCLUSIONS

For canine diabetic cataracts, phacoemulsification is recommended because it is superior to topical management alone in terms of maintaining vision and reducing the number of ophthalmic solutions required in the long term.

The Royal College of Ophthalmologists' National Ophthalmology Database study of cataract surgery: Report 9, Risk factors for posterior capsule opacification

BACKGROUND/OBJECTIVES

Posterior Capsule Opacification (PCO) is the most common long-term post-operative adverse occurrence after cataract surgery often requiring treatment with YAG laser posterior capsulotomy. This study aimed to identify potential risk factors, known at the time of cataract surgery, that influence the development of PCO.

SUBJECT/METHODS

A retrospective study of publicly funded cataract surgery from The Royal College of Ophthalmologists' National Ophthalmology Database. Eligible for analysis were 500,872 cataract operations performed in 41 participating centres.

RESULTS

The 500,872 operations were performed on 243,167 (48.5%) left eyes and 257,705 (51.5%) right eyes from 373,579 patients by 2196 surgeons. Post-cataract PCO was recorded for 61,778 (12.3%) eyes and the six month, one, three, five and nine year observed rates of PCO were 2.3%, 4.4%, 19.7%, 34.0% and 46.9% respectively. Different PCO profiles were observed between IOL materials and the identified risk factors that increased the risk of developing PCO included hydrophilic IOL material, axial length >26 mm, the presence of high myopia and implantation of lower IOL powers and previous vitrectomy surgery, along with younger age and female gender.

CONCLUSIONS

Many factors influence the development of PCO relating to the patient, the eye, the lens and the surgery. Some factors are modifiable such as IOL material, therefore the opportunity exists to attempt to reduce PCO rates, benefitting patients and the UK NHS.

Glutaredoxin 1 protects lens epithelial cells from epithelial-mesenchymal transition by preventing casein kinase 1α S-glutathionylation during posterior capsular opacification

Oxidative stress drives protein S-glutathionylation, which regulates the structure and function of target proteins and is implicated in the pathogenesis of many diseases. Glutaredoxin 1 (Grx1), a cytoplasmic deglutathionylating enzyme, maintains a reducing environment within the cell under various conditions by reversing S-glutathionylation. Grx1 performs a wide range of antioxidant activities in the lens and prevents protein-thiol mixed disulfide accumulation, reducing protein-protein aggregation, insolubilization, and apoptosis of lens epithelial cells. Oxidative stress is related to epithelial-mesenchymal transition (EMT) during posterior capsular opacification (PCO). However, whether Grx1-regulated protein S-glutathionylation plays an essential role in PCO remains unclear. In this study, we revealed that Grx1 expression was decreased in mice following cataract surgery. Furthermore, the absence of Grx1 elevated oxidative stress and protein S-glutathionylation and aggravated EMT in both in vitro and in vivo models. Concurrently, these results could be reversed by Grx1 overexpression. Notably, liquid chromatography-tandem mass spectrometry results showed that casein kinase 1α (CK1α) was susceptible to S-glutathionylation under oxidative stress, and CK1α S-glutathionylation (CK1α-SSG) was mediated at Cys249. The absence of Grx1 upregulated CK1α-SSG, subsequently decreasing the CK1α-induced phosphorylation of β-catenin at Ser45. The consequential downregulation of degradative β-catenin and upregulation of its nuclear translocation activated the Wnt/β-catenin signaling pathway and aggravated EMT. In conclusion, the downregulated expression of Grx1 in mice following cataract surgery aggravated EMT by upregulating the extent of CK1α-SSG. To the best of our knowledge, our study is the first to report how S-glutathionylation regulates CK1α activity under oxidative stress.

Dynamic changes of Elschnig pearls posterior capsule opacification

An adolescent female with underlying bilateral pseudophakia and idiopathic intermediate uveitis had reduced visual acuity due to posterior capsule opacification (PCO). The rapid progression and different morphological formations of Elschnig pearls were not influenced by the uveitis and immunosuppressive treatment. No capsulotomy was performed, and the PCO regressed spontaneously over time.

Early-Onset Posterior Capsule Opacification: Incidence, Severity, and Risk Factors

INTRODUCTION

To evaluate the incidence, severity, and risk factors of early-onset posterior capsule opacification (PCO) following uneventful phacoemulsification and intraocular lens (IOL) implantation.

METHODS

Patients with cataracts who underwent phacoemulsification and IOL implantation surgery for 3 months from September 2019 to April 2020 were enrolled. All the subjects completed a comprehensive ocular examination. Retroillumination images of the posterior capsule were obtained using a slit lamp with imaging system, and PCO was graded by two ophthalmologists. Univariate and multivariate logistic regression analyses were performed to assess the risk factors for PCO.

RESULTS

A total of 1039 subjects were enrolled, with mean age 66.68 ± 11.43 years and 42.06% were male. The incidence of early-onset PCO in the 3 months after cataract surgery was 29.93%, and PCO of grade 3 and grade 4 was present in 31 patients (2.98%). Patients with complicated cataract had a higher incidence of PCO than age-related cataract, especially for patients with previous pars plana vitrectomy (PPV) surgery (P < 0.001). Moreover, the incidence of PCO increased with the deficiency of capsulorhexis-IOL overlap (P < 0.001). Multivariate logistic regression also showed that previous PPV surgery (OR 2.664, P = 0.003) and incomplete capsulorhexis-IOL overlap were risk factors for PCO (180-360° overlap: OR 2.058, P < 0.001; < 180° overlap: OR 5.403, P < 0.001).

CONCLUSIONS

Larger capsulorhexis and PPV surgery history contribute to the occurrence of early-onset PCO, indicating that primary posterior continuous curvilinear capsulorhexis can be considered during cataract surgery for patients with PPV history.

The effect of sex on the mouse lens transcriptome

The transcriptome of mammalian tissues differs between males and females, and these differences can change across the lifespan, likely regulating known sexual dimorphisms in disease prevalence and severity. Cataract, the most prevalent disease of the ocular lens, occurs at similar rates in young individuals, but its incidence is elevated in older women compared to men of the same age. However, the influence of sex on the lens transcriptome was unknown. RNAseq based transcriptomic profiling of young adult C57BL/6J mouse lens epithelial and fiber cells revealed that few genes are differentially expressed between the sexes. In contrast, lens cells from aged (24 month old) male and female C57BL/6J mice differentially expressed many genes, including several whose expression is lens preferred. Like cataracts, posterior capsular opacification (PCO), a major sequela of cataract surgery, may also be more prevalent in women. Lens epithelial cells isolated from mouse eyes 24 h after lens fiber cell removal exhibited numerous transcriptomic differences between the sexes, including genes implicated in complement cascades and extracellular matrix regulation, and these differences are much more pronounced in aged mice than in young mice. These results provide an unbiased basis for future studies on how sex affects the lens response to aging, cataract development, and cataract surgery.