[Pathogenesis of cataract after vitrectomy]

Development of cystoid macular edema after uneventful cataract surgery in eyes with a history of vitrectomy using silicone oil versus gas tamponade

BACKGROUND/OBJECTIVES

The purpose of this study is to investigate whether history of silicone oil tamponade may predispose to the development of cystoid macular edema (CMO) following uneventful post-vitrectomy cataract surgery.

SUBJECTS/METHODS

This is a retrospective study that was conducted at a single academic institution. Records of patients who underwent pars plana vitrectomy (PPV) with or without silicone oil tamponade and subsequent cataract surgery between 2017-2020 were reviewed. Macular optical coherence tomography (OCT) findings up to 4 years after surgery were assessed.

RESULTS

A total of 95 eyes were included. Forty-one eyes underwent cataract surgery and had a history of PPV with silicone oil tamponade (Group 1). Fifty-four eyes underwent cataract surgery by phacoemulsification and had a history of PPV with gas tamponade (Group 2). Average follow up time after cataract surgery was 41.1 months. In Group 1, the incidence of OCT-detected CMO was 39.0%, compared to 27.8% in Group 2 (p = 0.247). The incidence of clinically significant CMO in Group 1 was 22.0%, compared to 18.5% in Group 2 (p = 0.679). The duration of CMO was significantly longer in Group 1 (p = 0.041) and cases were less likely to resolve by the last follow up visit (p = 0.040).

CONCLUSIONS

The incidence of OCT-detected or clinically significant pseudophakic CMO is not significantly different between eyes with prior PPV with gas tamponade versus silicone oil tamponade. However, CMO after uneventful cataract surgery may have a prolonged course if there is history of silicone oil tamponade, requiring longer treatment.

A bibliometric and visualized analysis of the pathogenesis of cataracts from 1999 to 2023

Research on the pathogenesis of cataracts is ongoing and the number of publications on this topic is increasing annually. This study offers an overview of the research status, popular topics, and scholarly tendencies in the field of cataract pathogenesis over recent decades，which helps to guide future research directions, and optimize resource allocation. In the present study, we performed a bibliometric analysis of cataract pathogenesis. Publications from January 1, 1999, to December 20, 2023, were collected from the Web of Science Core Collection (WoSCC), and the extracted data were quantified and analyzed. We analyzed and presented the data using Microsoft Excel, VOSviewer, CiteSpace, and Python. In all, 4006 articles were evaluated based on various characteristics, including publication year, authors, countries, institutions, journals, citations, and keywords. This study utilized VOSviewer to conduct visualized analysis, including co-authorship, co-citation, co-occurrence, and network visualization. The CiteSpace software was used to identify keywords with significant bursts of activity. The number of annual global publications climbed from 76 to 277 between 1999 and 2023, a 264.47% rise. Experimental Eye Research published the most manuscripts (178 publications), whereas Investigative Ophthalmology & Visual Science received the most citations (6675 citations). The most influential and productive country, institution, and author were the United States (1244 publications, 54,456 citations), University of California system (136 publications, 5401 citations), and Yao Ke (49 publications, 838 citations), respectively. The top 100 ranked keywords are divided into four clusters through co-occurrence analysis: (1) secondary cataracts, (2) oxidative stress, (3) gene mutations and protein abnormalities, and (4) alteration of biological processes in lens epithelial cells. Further discussions on the four subtopics outline the research topics and trends. In conclusion, the specific mechanism of cataract formation remains a popular topic for future research and should be explored in greater depth.

Fibrotic cataract as a sign of posterior capsule violation post vitrectomy

Purpose

To report fibrotic cataract as a sign of posterior capsule violation post vitrectomy.

Observations

A 16 year old female presented to our retina clinic after multiple prior vitrectomies at an outside hospital for traumatic retinal detachment. On presentation, it was noted that she still had a silicone oil inside the eye, and a dense, fibrotic cataract limiting the posterior pole view. The decision was made to pursue cataract phacoemulsification plus silicone oil removal. We utilized the Zepto capsulotomy system given the white cataract. After gentle bimanual irrigation and aspiration of the cataract, it was discovered there were two small, round, posterior capsule defects with fibrosis around these holes that extended anteriorly, involving the capsular fornix and anterior capsule. This was confirmed intraoperatively on heads-up OCT. A three-piece intraocular lens was placed into the capsular bag, but given the contracted capsular fornix, the IOL was decentered inferonasally, so it was repositioned in the sulcus with good centration.

Conclusions

It is known that pars plana vitrectomy leads to accelerated cataract formation postoperatively. This case report is the first to our knowledge that describes a fibrotic cataract as a sign of posterior capsular violation.

Importance

We demonstrate that presence of fibrotic cataract post vitrectomy should raise suspicion for capsular violation and should prompt further discussion with the patient regarding appropriate surgical planning and expectations.

Refractive Outcomes and Anterior Chamber Depth after Cataract Surgery in Eyes with and without Previous Pars Plana Vitrectomy

Purpose: To compare the differences in refractive outcome and anterior chamber depth (ACD) after phacoemulsification between eyes with and without previous pars plana vitrectomy (PPV).Materials and Methods: Patients who had significant cataracts after PPV were included in the study group, and patients with a matched axial length (AL) who had cataracts without PPV were selected as the control group. The performance of new generation intraocular lens (IOL) power calculation formulas (Barrett Universal II, Kane, Ladas Super formulas), and the traditional formulas (SRK/T, Holladay 1, Hoffer Q, Haigis) with and without the Wang-Koch (WK) AL adjustment were compared between the two groups. The postoperative ACD was measured using the Scheimpflug imaging system with manual correction at least three months after surgery. Results: In total, there were 193 eyes from 193 patients in each group. The mean prediction errors (MEs) of the new generation formulas had no significant systemic bias in the study group; the hyperopic shift was displayed in the traditional formulas for eyes with AL > 26mm. However, the difference of MEs between the two groups among all the formulas were not significant. The absolute prediction error (MAE) and median prediction error (Med AE) in the study group were larger than those in the control group among all the formulas. The postoperative ACD of the study group was deeper but not significant than that of the control group. Conclusions: There was no refractive shift in vitrectomized eyes compared with non-vitrectomized eyes no matter in new generation formulas or traditional vergence formulas. The prediction error among all the formulas in vitrectomized eyes were significantly higher than those in non-vitrectomized eyes. The ACD after phacoemulsification in vitrectomized eyes was not significantly different from non-vitrectomized eyes.

Combining cataract surgery with 25-gauge high-speed pars plana vitrectomy: A prospective study

PURPOSE

To compare visual outcome and postoperative complications of combined 25-gauge pars plana vitrectomy and phacoemulsification with vitrectomy alone surgery in patients with epiretinal membrane and macular hole.

METHODS

A total of 110 eyes (73 eyes with epiretinal membrane and 37 eyes with macular hole) were enrolled in this prospective study. The eyes were divided into two groups: Group A included 55 eyes which underwent phacovitrectomy at the same time and Group B included 55 eyes which underwent vitrectomy alone. Follow-up visits were at 1, 3, and 6 months.

RESULTS

The best-corrected visual acuity correlation by analysis of variance measurement showed statistically non-significant differences between the two groups (p = 0.32). The post hoc analysis from baseline, 1°, 2°, and 3° follow-ups was not statistically significant (p > 0.05). The most common postoperative complication was cystoid macular edema that has been detected in 11 patients (10%) (seven eyes in Group A and four eyes in Group B): 2 patients (1.8%) developed a chronic macular edema. Intraocular hypertension occurred in five eyes (4.5%) (three in Group A and two in Group B). Four eyes (3.6%) underwent another surgical procedure for a persistent macular hole (two in Group A and two in Group B). The intraocular lens repositioning was performed one day after surgery in three eyes (2.7%) (Group A). The mean preoperative visual acuity was not different between the two groups (p = 0.80).

CONCLUSION

No significative differences between combined surgery and vitrectomy alone have been detected, in terms of postoperative complications and visual outcome.

Modified Vitrectomy Technique for Phakic Rhegmatogenous Retinal Detachment with Intermediate Break

Purpose

To evaluate the effects of a modification of the traditional 25-gauge pars plana vitrectomy technique in the treatment of uncomplicated macula-on rhegmatogenous retinal detachment (RRD) with intermediate retinal break(s) and marked vitreous traction in the phakic eye.

Methods

Prospective, noncomparative, and interventional case series. All consecutive phakic eyes with primary uncomplicated macula-on RRD with intermediate retinal break(s) and marked vitreous traction, with at least 1 year of postoperative follow-up, were enrolled. In all eyes, "localized 25-gauge vitrectomy" under air infusion with localized removal of the vitreous surrounding the retinal break(s), in association with laser photocoagulation and air tamponade, was performed. The primary end point was the rate of primary retinal attachment. Secondary end points were cataract progression and assessed by digital Scheimpflug lens photography (mean change of nuclear density units) and the rate of complications.

Results

Thirty-two phakic eyes were included in the final analysis. At 12 months, the primary outcome of anatomical success was achieved in 94% of eyes. The mean nuclear density units did not change significantly at any time point during the follow-up. After localized vitrectomy, one eye developed an epiretinal membrane, and one eye developed cystoid macular edema; no other significant complications were reported.

Conclusions

"Localized vitrectomy" has a high anatomical success rate in phakic eyes with primary uncomplicated macula-on RRD with intermediate retinal break(s) and marked vitreous traction, without causing progression of cataract.

Expressions of TGF-β2, bFGF and ICAM-1 in lens epithelial cells of complicated cataract with silicone oil tamponade

AIM

To investigate the expression differences of transforming growth factor-β2 (TGF-β2), basic fibroblast growth factor (bFGF) and intercellular cell-adhesion molecule-1 (ICAM-1) in lens epithelial cells (LECs) of complicated cataract with silicone oil tamponade and age-related cataract.

METHODS

Totally 150 eyes of 150 patients (aged 35 to 77y) were investigated, including 75 patients with complicated cataract after silicone oil tamponade and 75 patients with age-related cataract. The central piece of anterior capsules was collected during cataract surgery. TGF-β2, bFGF and ICAM-1 were detected in the 60 specimens of the two groups by immunohistochemistry. The expression levels of the three kinds of messenger ribonucleic acid (mRNA) were determined by real-time quantitative reverse transcription-polymerase chain reaction in the 90 specimens of the two groups.

RESULTS

TGF-β2 was detected in the cytomembrane and cytoplasm of the LECs and bFGF was detected in the nucleus. ICAM-1 was positive in the cytomembrane of the LECs and the distribution of positive cells was uneven. The mRNA genes expression of the TGF-β2, bFGF and ICAM-1 was significant differences between the two groups and markedly increased in complicated cataract group (P<0.05).

CONCLUSION

The up-regulated TGF-β2, bFGF and ICAM-1 maybe associate with the occurrence and development of complicated cataract with silicone oil tamponade.

Apoptosis Factors of Lens Epithelial Cells Responsible for Cataractogenesis in Vitrectomized Eyes with Silicone Oil Tamponade

Background

The aim of this study was to determine the expression of apoptotic factors Bax, Bcl-2, and Caspase-3 in lens epithelial cells (LECs) from cataracts secondary to pars plana vitrectomy with silicone oil (SO) tamponade. We also investigated the impact of SO emulsification on the expression of apoptotic factors.

Material/Methods

Anterior capsulotomy specimens of 20 eyes in 20 patients with cataract secondary to SO tamponade (Group 2), were collected. Another 20 eyes of 20 patients with age-related cataract (Group 1) were recruited as controls. The anterior capsule specimens were obtained from the patients during cataract surgery, frozen and later analyzed with respect to immunohistochemical stains of Bax, Bcl-2, and Caspase-3 using a confocal microscope.

Results

Age, sex, and laterality did not show any difference between the 2 groups. There was a greater increase in Bax and Caspase-3 expression in LEC in Group 2 than in Group 1 (P_Bax<0.0001, P_Caspase-3<0.0001). The Bcl-2 expression decreased in Group 2, although the difference was not significant (P=0.616). The changes of apoptosis factors are not associated to SO emulsification (P_Bax=0.354, P_Bcl-2=0.728, P_Caspase-3=0.939).

Conclusions

The caspase-3-dependent apoptosis of LECs increased in complicated cataract patients with SO endotamponade. The Bax played a critical role in regulating apoptosis of LECs in vitrectomized eyes with SO tamponade. The SO emulsification had no significant impact on the expression of apoptosis factors.

αA-crystallin gene CpG islands hypermethylation in nuclear cataract after pars plana vitrectomy

PURPOSE

To investigate the DNA methylation status of αA-crystallin gene in cataract secondary to pars plana vitrectomy.

METHODS

Anterior capsular membranes of 40 eyes of 40 patients with cataract secondary to vitrectomy were collected. Another 20 eyes of 20 patients who received pars plana vitrectomy and phacoemulsification in the primary procedure, were recruited as control. Methylation status of the CpG islands of αA-crystallin gene was analyzed by pyrosequencing. Expression of αA-crystallin was evaluated by real-time polymerase chain reaction and western blot.

RESULTS

In the post vitrectomy group, five patients with posterior subcapsular opacity and four patients with cortical opacity were excluded from further analysis. The remaining 31 patients with nuclear cataract were assigned into two groups according to tamponade types: 19 of octafluoropropane (C3F8) and 12 of silicone oil (SiO). The average nuclear color grading was elevated both in C3F8 and SiO groups after vitrectomy. Compared to the control group, hypermethylation of the CpG islands in the αA-crystallin gene promoter was found in both post vitrectomy groups, accompanied by significantly reduced αA-crystallin expression. No statistically significant differences were found between the C3F8 and SiO groups either for DNA methylation status or αA-crystallin expression.

CONCLUSIONS

CpG islands hypermethylation of αA-crystallin gene may be involved in nuclear cataract formation after pars plana vitrectomy.