Vitrectomy surgery increases oxygen exposure to the lens: a possible mechanism for nuclear cataract formation

Topical Instillation of N-Acetylcysteine and N-Acetylcysteine Amide Impedes Age-Related Lens Opacity in Mice

Cataracts, the leading cause of blindness globally, are caused by oxidative stress and inflammation, which disrupt lens transparency due to increased accumulation of reactive oxygen species (ROS) as well as protein and DNA damage during aging. Using in vitro, ex vivo, and in vivo models, we determined the protective efficacy of N-acetylcysteine amide (NACA) against oxidative stress-induced and aging-induced cataractogenesis. We found that lens epithelial cells exposed to the oxidative stress inducers hydrogen peroxide (H2O2) or tert-butyl hydroperoxide showed significant ROS accumulation and reduced cellular viability. These effects were inhibited by NACA via the suppression of ROS and thioredoxin-interacting protein (Txnip) expression, a regulator of oxidative stress-related cellular damage and inflammation. In ex vivo lens experiments, NACA significantly reduced H2O2-induced lens opacity and preserved lens integrity. Similarly to NACA-treated lenses ex vivo, the integrity and opacity of aged mouse lenses, when topically instilled with NACA, were preserved and reduced, respectively, and are directly related to reduced Txnip and increased thioredoxin (Trx) expression levels. Overall, our findings demonstrated the protective ability of NACA to abate aberrant redox-active pathways, particularly the ROS/TRX/TXNIP axis, thereby preventing cataractogenesis and preserving eye lens integrity and ultimately impeding aging-related cataracts.

Risk factors for hyphema following pars plana vitrectomy with intravitreal gas injection in vitreoretinal disease

PURPOSE

To investigate the risk factors and outcomes associated with hyphema after pars plana vitrectomy (PPV) with intravitreal gas injection.

METHODS

A retrospective study was conducted on 252 patients (252 eyes) who underwent PPV with intravitreal gas injection between January 1, 2011, and August 30, 2023. Patients were grouped based on the presence of hyphema within one week postoperatively. We analyzed the clinical characteristics of the patients, surgical procedures, and the risk factors associated with the occurrence of hyphema.

RESULTS

Postoperative hyphema developed in 16 (6.3%) eyes. The hyphema group was significantly younger (54.00 ± 10.88 years vs. 61.06 ± 12.41 years, P = 0.027) compared to the non-hyphema group. Additionally, the hyphema group had a higher percentage of high myopia (68.8% vs. 19.1%, P < 0.001) and a longer surgical duration (89.00 ± 33.35 min vs. 71.00 ± 28.64 min, P = 0.017) compared to the non-hyphema group. The anatomical success rate of the primary surgery at 6 months did not differ significantly between the hyphema and non-hyphema groups (93.8% vs. 95.3%, P = 0.773). High myopia (OR, 10.014; 95% CI 3.211-31.235; P < 0.001) and longer surgical duration (min) (OR, 1.019; 95% CI 1.003-1.035; P = 0.019) were significantly associated with the occurrence of hyphema.

CONCLUSION

High myopia and longer surgical duration were risk factors for hyphema development after PPV with intravitreal gas injection. Hyphema occurrence may not have had a significant impact on the anatomical success rate at 6 months.

Premacular membranes and glaucoma: a review of clinical and therapeutic considerations

PURPOSE

Primary epiretinal, or more precisely termed pre macular membranes (PMM) and glaucomatous optic neuropathy are both common conditions affecting a predominantly elderly population. There are several relevant clinical and pathological considerations when they are both diagnosed in the same eye.

METHODS

We systematically searched the literature to review the challenges clinicians must address when dealing with patients with co-existing PMM and glaucoma.

RESULTS

Although the current literature is limited there appears to be a link between the occurrence of glaucomatous optic neuropathy and idiopathic PMM. The presence of PMM can confound glaucomatous progression detection on optical coherence tomography (OCT). Vitrectomy and membrane peeling may improve vision in some patients with co-existing disease but there may be an increased risk of glaucoma progression particularly in eyes with advanced glaucoma and more extensive neuronal loss. Peeling of the retinal inner limiting membrane in addition to PMM peeling may result in an increased risk of visual loss. Inner nuclear layer hypo-reflective spaces on OCT are particularly prevalent in eyes with glaucoma and PMM and may be a negative prognostic sign for outcome.

CONCLUSION

Patients should be counseled regarding the guarded prognosis, and careful consideration given to the benefits of PMM surgery. Further research is needed to guide clinical practice.

Understanding cataract development in axial myopia: The contribution of oxidative stress and related pathways

Myopia is an evolving global health challenge, with estimates suggesting that by 2050 it will affect half of the world's population, becoming the leading cause of irreversible vision loss. Moreover, myopia can lead to various complications, including the earlier onset of cataracts. Given the progressive aging of the population and the increase in life expectancy, this will contribute to a rising demand for cataract surgery, posing an additional challenge for healthcare systems. The pathogenesis of nuclear and posterior subcapsular cataract (PSC) development in axial myopia is complex and primarily involves intensified liquefaction of the vitreous body, excessive production of reactive oxygen species, impaired antioxidant defense, and chronic inflammation in the eyeball. These factors contribute to disruptions in mitochondrial homeostasis, abnormal cell signaling, lipid peroxidation, protein and nucleic acid damage, as well as the induction of adverse epigenetic modifications. Age-related and oxidative processes can cause destabilization of crystallins with subsequent protein accumulation, which finally drives to a lens opacification. Moreover, an altered redox status is one of the major contributors to the pathogenesis of PSC. This review aims to summarize the mechanisms known to be responsible for the accelerated development of cataracts in axial myopia and to enhance understanding of these relationships.

Vision degrading myodesopsia from vitreous floaters in the young: An important aspect of myopia

Vitreous floaters are visual phenomena resulting from floating opacities inside the eye that disturb vision. The opacities consist of microscopic collagen fibers that aggregate in myopia and during aging. These collagen fibers are then seen as irregular, sometimes worm-like shadows or structures of a translucent to black color. Because of the floating aspect, they tend to follow the movements of the eye, causing distress and having a negative impact on a patient's quality of life due to degradation in contrast sensitivity function. This is referred to as vision degrading myodesopsia (VDM). The overall importance of floaters and their effect on quality of life gained attention in recent years. While the existence of floaters alone is labeled as harmless, there is an increasing group of young people suffering from VDM. This coincides with the growing prevalence of myopia. Indeed, myopia and myopic vitreopathy are the major causes of VDM in the young. This aspect of myopia, however, is often overlooked. We review the current research status in floater formation, quality of life impact, symptom assessment, localization and therapeutic options for vitreous floaters from the perspective of a myopic, potentially younger patient group.

Differential Signaling Pathways Identified in Aqueous Humor, Anterior Capsule, and Crystalline Lens of Age-Related, Diabetic, and Post-Vitrectomy Cataract

Background: The purpose of this study was to detect proteomic alterations and corresponding signaling pathways involved in the formation of age-related cataract (ARC), diabetic cataract (DC), and post-vitrectomy cataract (PVC). Methods: Three sample types, the aqueous humor (AH), the anterior capsule (AC), and the content of the phaco cassette, were collected during phacoemulsification surgery. The samples were obtained from 12 participants without diabetes mellitus (DM), 11 participants with DM, and 7 participants without DM, with a history of vitrectomy surgery in the past 12 months. The Sp3 protocol (Single-Pot, Solid-Phase, Sample-Preparation) was used for the sample preparation. The recognition and quantification of proteins were carried out with liquid chromatography online with tandem mass spectrometry. The DIA-NN software was applied for the identification and quantification of peptides/proteins. Statistical analysis and data visualization were conducted on Perseus software. Data are available via ProteomeXchange. Results: A very rich atlas of the lens and AH proteome has been generated. Glycosaminoglycan biosynthesis and the non-canonical Wnt receptor signaling pathway were differentially expressed in ARC compared to both the DC and PVC groups. In the PVC group, complement activation was differentially expressed in AH samples, while glutathione metabolism and oxidoreductase activity were differentially expressed in AC samples. Microfilament motor activity, microtubule cytoskeleton organization, and microtubule binding were differentially expressed in the DC and PVC groups in both AH and AC samples. Conclusions: The results of this study expand the existing knowledge on pathways involved in the pathophysiology of cataract, and suggest possible important druggable targets for slower progression or even prevention of cataract.

Challenges and outcomes of cataract surgery after vitrectomy

PURPOSE OF REVIEW

This review examines the challenges and outcomes of cataract surgery after pars plana vitrectomy (PPV), focusing on surgical techniques, timing, and complication management.

RECENT FINDINGS

Cataract formation remains the primary complication post-PPV, affecting approximately 80-100% of patients within two years. Nuclear sclerotic cataracts are most common, occurring in 60-100% of patients over 50, followed by posterior subcapsular cataracts (4-34%), which primarily affect younger and diabetic patients. PPV disrupts the normal oxygen gradient in the vitreous, resulting in a more uniform oxygen distribution and accelerating cataract formation.Post-PPV eyes present unique surgical challenges due to anatomical alterations, including zonular instability and capsular changes characterized by increased fragility, the potential for tears, and altered elasticity. Newer intraocular lens power calculations show promise, but unexpected refractive outcomes may occur. The choice between combined phacovitrectomy and sequential surgeries remains debated, with patient-specific factors guiding the approach. Visual outcomes vary depending on preexisting vitreoretinal pathologies and baseline vision before PPV. Further randomized controlled trials are needed to establish treatment guidelines and improve predictive models.

SUMMARY

Post-PPV cataract surgery presents unique challenges, including anatomical alterations and an increased risk of capsular complications. These necessitate careful consideration of the surgical approach and highlight the need for further research to optimize outcomes and establish treatment guidelines.

Ultrastructural investigation of the posterior hyaloid membrane in posterior vitreous detachment

BACKGROUND

Separation of the posterior hyaloid membrane (PHM) from the retina in posterior vitreous detachment (PVD) is a fundamental, but poorly understood, process underlying vitreoretinal disorders including retinal detachment and macular hole. We performed electron microscopy studies of the PHM after PVD to investigate its ultrastructure, associated cellular structures and relationship to the internal limiting membrane (ILM).

METHODS

Post-mortem human eyes were collected from recently deceased patients over 70 years of age. A posterior scleral button was trephined to identify PVD status, and the PHM and vitreous prepared for analysis with transmission and scanning electron microscopy.

RESULTS

Twelve eyes from six patients were collected. Seven eyes had PVD; five eyes had attached vitreous. PHM was isolated from seven of seven eyes with PVD. The PHM in eyes with PVD is a laminar lacy sheet, distinct from the disorganised fibres of vitreous gel. Eyes without PVD had vitreous encased in internal limiting membrane which had separated en bloc from the retina. Cells embedded in the PHM (laminocytes) were identified in five of seven eyes with PVD, with strands stretching into the membrane.

CONCLUSIONS

PHM isolated from eyes with PVD is distinct from artefactual separation of the ILM from the retina during dissection. PHM is ultrastructurally distinct from vitreous gel and is a separate entity. The en face appearance of PHM is similar to that of ILM, suggesting that in PVD, PHM forms from separation of an inner layer of ILM. Laminocytes may play a role in the pathogenesis of vitreoretinal disease.

In Vivo Assessment of an Antioxidant Hydrogel Vitreous Substitute

The vitreous humor undergoes liquefaction with age, resulting in complications that may require a vitrectomy, or surgical removal of the vitreous from the eye. Silicone oil, a common vitreous substitute, lacks properties similar to the natural vitreous. In particular, it lacks antioxidants that may be necessary to reduce oxidative stress in the eye. The purpose of this study was to evaluate antioxidant-loaded hydrogel vitreous substitutes in a pilot in vivo study. Ascorbic acid and glutathione were loaded into synthesized PEGDA hydrogels. Following vitrectomy, experimental antioxidant hydrogels or silicone oil were injected into one eye of rabbits, while the other eye served as untreated or sham control. Ophthalmic assessments, including electroretinography, were performed. Levels of glutathione and ascorbic acid were higher in the eyes treated with the antioxidant-loaded hydrogel vitreous substitute, although this was not found to be significant after 28 days. There were no statistically significant differences between groups with respect to clinical examination, and ocular health scores, electroretinograms, and histology were normal. These results indicate minimal concerns for the hydrogel formulation or high levels of antioxidants. Future research will assess the capability of vitreous substitutes to prolong antioxidant release, with the goal of minimizing cataract after vitrectomy.

Minimizing Oxidative Stress in the Lens: Alternative Measures for Elevating Glutathione in the Lens to Protect against Cataract

Oxidative stress plays a major role in the formation of the cataract that is the result of advancing age, diabetes or which follows vitrectomy surgery. Glutathione (GSH) is the principal antioxidant in the lens, and so supplementation with GSH would seem like an intuitive strategy to counteract oxidative stress there. However, the delivery of glutathione to the lens is fraught with difficulties, including the limited bioavailability of GSH caused by its rapid degradation, anatomical barriers of the anterior eye that result in insufficient delivery of GSH to the lens, and intracellular barriers within the lens that limit delivery of GSH to its different regions. Hence, more attention should be focused on alternative methods by which to enhance GSH levels in the lens. In this review, we focus on the following three strategies, which utilize the natural molecular machinery of the lens to enhance GSH and/or antioxidant potential in its different regions: the NRF2 pathway, which regulates the transcription of genes involved in GSH homeostasis; the use of lipid permeable cysteine-based analogues to increase the availability of cysteine for GSH synthesis; and the upregulation of the lens's internal microcirculation system, which is a circulating current of Na+ ions that drives water transport in the lens and with it the potential delivery of cysteine or GSH. The first two strategies have the potential to restore GSH levels in the epithelium and cortex, while the ability to harness the lens's internal microcirculation system offers the exciting potential to deliver and elevate antioxidant levels in its nucleus. This is an important distinction, as the damage phenotypes for age-related (nuclear) and diabetic (cortical) cataract indicate that antioxidant delivery must be targeted to different regions of the lens in order to alleviate oxidative stress. Given our increasing aging and diabetic populations it has become increasingly important to consider how the natural machinery of the lens can be utilized to restore GSH levels in its different regions and to afford protection from cataract.

Increased late-onset glaucoma risk following vitrectomy for macular pucker or hole

OBJECTIVES

The long-term risk of developing glaucoma after vitrectomy remains uncertain. This retrospective population-based cohort study aimed to explore this risk following vitrectomy for macular pucker or hole.

METHODS

Utilizing Taiwan's National Health Insurance Research Database (NHIRD), we included patients who were older than 18 years and had undergone vitrectomy surgery between 2011 and 2019. Exclusions were made for patients with prior diagnoses of glaucoma, congenital or secondary glaucoma, as well as those who had received previous vitreoretinal treatments or had undergone multiple vitrectomies.

RESULTS

After an average follow-up period of 51 and 53 months respectively for the vitrectomized and non-vitrectomized group, our results showed a relative risk of 1.71 for glaucoma development in the vitrectomized group. Higher adjusted hazard ratios were also observed for open-angle glaucoma and normal tension glaucoma. Increased risks were associated with male sex, obstructive sleep apnoea, and migraine. In the subgroup analysis, phakic eyes at baseline and those who had undergone cataract surgery post-vitrectomy were associated with a lower risk of glaucoma development during follow-up. Among all glaucoma events, pseudophakic status at baseline had the shortest interval to glaucoma development following vitrectomy.

CONCLUSIONS

These findings underscore the potential relationship between vitrectomy and glaucoma onset, emphasizing the need for vigilant monitoring and early detection of glaucoma in post-vitrectomy patients.

Clinical features of retinal detachment treated with segmental scleral buckling

PURPOSE

Our study aims to evaluate the surgical outcomes and clinical features of retinal detachment (RD) cases treated with segmental scleral buckling (SB), elucidating the role of segmental SB as a vital option in specific situations during the current era.

METHODS

We retrospectively reviewed 128 eyes with primary rhegmatogenous RD that underwent segmental scleral buckling between November 2008 and December 2020. Clinical features and success rates were recorded and analyzed.

RESULTS

A total of 128 eyes were included. The patient's ages ranged from 12 to 72 years, with a median age of 45. Most of the eyes were phakic (97%). Regarding the type of break, 47% were holes, and flap tears were found in 68 cases (53%). The break locations were superior-temporal (54%), inferior-temporal (31%), superior-nasal (9.5%), and inferior-nasal (5.5%). The length of the SB applied ranged from 3.5 to 8.0 clock hours, with a median of 6.0. Primary success was achieved in 121 eyes, and recurrence occurred in 7 eyes. All recurrent RD cases reattached after undergoing secondary VT. The causes of failure included 2 break reopens, 1 missed break, and 4 eyes with proliferative vitreoretinopathy. The single-surgery anatomic success (SSAS) rate for segmental SB was 94.5%. The final success rate was 100%.

CONCLUSIONS

For phakic, low complexity retinal detachment in our study, segmental scleral buckling emerges as a surgical option with a high primary success rate and a lower incidence of complications.

Preoperative Visual Acuity Thresholds in Pars Plana Vitrectomy for Epiretinal Membrane: A Systematic Review

BACKGROUND AND OBJECTIVE

This review consolidates findings from studies that used a preoperative visual acuity (VA) threshold as an indication for epiretinal membrane (ERM) surgery.

METHODS

The literature was systematically searched using Ovid MEDLINE, EMBASE, and Cochrane Library from January 2000 to October 2022 to select studies reporting on pars plana vitrectomy (PPV) for ERM that used a preoperative VA threshold as an inclusion criterion. Primary outcomes were final best-corrected visual acuity (BCVA) and change in BCVA relative to baseline. Secondary outcomes included risk of intra- and postoperative complications.

RESULTS

A total of 639 eyes from seven studies were included. The most liberal preoperative VA threshold was 20/28.5 or worse, whereas the most conservative threshold was worse than 20/60. The mean preoperative BCVA was 0.55 logarithm of the minimum angle of resolution (logMAR) (∼20/70), and the mean postoperative BCVA was 0.35 logMAR (∼20/45). Generally, VA improved relative to baseline, regardless of the preoperative VA threshold. The smallest improvement in VA was observed in a study where the pre-operative VA to consider surgery was liberal (20/30 or worse), whereas the greatest VA improvement was observed in a study that used a conservative preoperative VA threshold (worse than 20/60).

CONCLUSIONS

The greatest improvement in BCVA was observed in studies where a conservative pre-operative VA threshold was used. The decision to operate should involve a patient-centered approach with a thorough discussion of the risks and benefits of PPV, regardless of the preoperative VA threshold used. [Ophthalmic Surg Lasers Imaging Retina 2024;55:400-407.].

Causal association between 25-hydroxyvitamin D status and cataract development: A two-sample Mendelian randomization study

BACKGROUND

Vitamin deficiencies are linked to various eye diseases, and the influence of vitamin D on cataract formation has been noted in prior research. However, detailed investigations into the causal relationship between 25-(OH)D status and cataract development remain scarce.

AIM

To explore a possible causal link between cataracts and vitamin D.

METHODS

In this study, we explored the causal link between 25-(OH)D levels and cataract development using Mendelian randomization. Our analytical approach included inverse-variance weighting (IVW), MR-Egger, weighted median, simple mode, and weighted mode methods. The primary analyses utilized IVW with random effects, supplemented by sensitivity and heterogeneity tests using both IVW and MR-Egger. MR-Egger was also applied for pleiotropy testing. Additionally, a leave-one-out analysis helped identify potentially impactful single-nucleotide polymorphisms.

RESULTS

The analysis revealed a positive association between 25-(OH)D levels and the risk of developing cataracts (OR = 1.11, 95%CI: 1.00-1.22; P = 0.032). The heterogeneity test revealed that our IVW analysis exhibited minimal heterogeneity (P > 0.05), and the pleiotropy test findings confirmed the absence of pleiotropy within our IVW analysis (P > 0.05). Furthermore, a search of the human genotype-phenotype association database failed to identify any potentially relevant risk-factor single nucleotide polymorphisms.

CONCLUSION

There is a potential causal link between 25-(OH)D levels and the development of cataracts, suggesting that greater 25-(OH)D levels may be a contributing risk factor for cataract formation. Further experimental research is required to confirm these findings.

Combined phacovitrectomy versus sequential surgery for idiopathic macular holes: systematic review and meta-analysis

OBJECTIVE

To compare the best-corrected visual acuity (BCVA) change, idiopathic macular (IMH) closure, and complications in IMH patients receiving combined phacovitrectomy and sequential surgery (vitrectomy followed by phacoemulsification).

DESIGN

Systematic review and meta-analysis.

METHODS

PubMed, Ovid EMBASE, and Cochrane Library databases were searched from their inception through February 2022. Randomized, controlled trials and observational studies that presented results of BCVA change, IMH closure, and surgery-related complications were included. A random-effects meta-analysis was conducted to calculate effect estimates with 95% CIs.

RESULTS

One randomized, controlled trials and 7 cohort studies with 585 patients were included. Overall, the meta-analyses of BCVA change (mean difference, -0.03; 95% CI, -0.10-0.04) and IMH closure (risk ratio = 1.04; 95% CI, 0.96-1.13) revealed no significant differences between combined phacovitrectomy and sequential surgery. The pooled risk ratios for various surgical complications such as postoperative retinal detachment, inflammation, and intraocular pressure elevation showed no significant differences between the 2 groups.

CONCLUSIONS

Similar visual gain and IMH closure rates were achieved after both combined phacovitrectomy and sequential surgery, with similar complication risks. The anatomic and functional outcomes of combined surgery were not better than those of sequential surgery. These results could serve as a reference for future trials.

Desired properties of polymeric hydrogel vitreous substitute

Vitreous replacement is a commonly employed method for treating a range of ocular diseases, including posterior vitreous detachment, complex retinal detachment, diabetic retinopathy, macular hole, and ocular trauma. Various clinical substitutes for vitreous include air, expandable gas, silicone oil, heavy silicone oil, and balanced salt solution. However, these substitutes have drawbacks such as short retention time, cytotoxicity, high intraocular pressure, and the formation of cataracts, rendering them unsuitable for long-term treatment. Polymeric hydrogels possess the potential to serve as ideal vitreous substitutes due to their structure-mimicking to natural vitreous and adjustable mechanical properties. Replacement with hydrogels as the tamponade can help maintain the shape of the eyeball, apply pressure to the detached retina, and ensure the metabolic transport of substances without impairing vision. This literature review examines the required properties of artificial vitreous, including the optical properties, rheological properties, expansive force action, and physiological and biochemical functions of chemically and physically crosslinked hydrogels. The strategies for enhancing the biocompatibility and injectability of hydrogels are also summarized and discussed. From a clinical ophthalmology perspective, this paper presents the latest developments in vitreous replacement, providing clinicians with a comprehensive understanding of hydrogel clinical applications, which offers guidance for future design directions and methodologies for hydrogel development.

Cataract progression after primary pars plana vitrectomy for uncomplicated rhegmatogenous retinal detachments in young adults

BACKGROUND

Scleral buckling is typically implemented to repair rhegmatogenous retinal detachments (RRD) in young patients. Therefore, there is limited data on post-pars plana vitrectomy (PPV) cataract formation in this cohort. We report the rates and risk factors of cataract progression after PPV for RRD repair in young eyes.

METHODS

Retrospective single-center cohort study. Medical records of patients between the ages of 15 to 45 undergoing PPV for uncomplicated RRD between 2014 and 2020 were reviewed.

RESULTS

Twenty-eight eyes from 26 patients met inclusion criteria. Cataracts developed in 20/28 (71%) eyes after PPV. After PPV, nuclear sclerotic cataract (NSC) rates were higher in patients above 35 (65%) compared to below 35 years (18%) (p = 0.024). Cataracts developed more frequently after macula-off RRDs (88%) compared to macula-on RRDs (50%) (p = 0.044) with NSC more common in macula-off detachments (p = 0.020). At postoperative month 2, all eyes with C3F8 gas developed cataracts compared to 59% of eyes with no gas (p = 0.040).

CONCLUSIONS

Cataract formation was common and frequent after PPV. After PPV, young eyes and macula-on detachments developed cataracts less frequently than older eyes and macula-off detachments. If appropriate, a shorter acting gas tamponade should be considered in young eyes to minimize cataract formation.

Risk Factors and Management of Intraocular Pressure Elevation After Vitrectomy Combined with Silicone Oil Tamponade

Silicone oil has emerged as the common option for intraocular tamponade during complicated retina vitrectomy. However, the postoperative elevation of intraocular pressure (IOP), influenced by numerous factors, remains a significant and frequently encountered complication that poses a potential threat to vision. Extensive research has been conducted to investigate the risk factors associated with elevated IOP following silicone oil tamponade, including silicone oil viscosity, preoperative high IOP, diabetes, and lens status. This comprehensive review aims to gather and summarize the current research findings regarding the risk factors contributing to IOP elevation following silicone oil tamponade, as well as the optimal management strategies for secondary glaucoma. The analysis includes the physicochemical properties of silicone oil, preoperative and intraoperative risk factors, and the effective management of secondary glaucoma. Enhancing our understanding of the primary factors associated with silicone oil-induced IOP elevation will facilitate the guidance of timely and appropriate interventions.

IMPLICATIONS OF COMPLETE POSTERIOR VITREOUS DETACHMENT IN EYES WITH CENTRAL RETINAL VEIN OCCLUSION

BACKGROUND/PURPOSE

To evaluate the status of the posterior vitreous hyaloid on presenting optical coherence tomography images of the macula and its relationship to clinical characteristics, treatment patterns, and outcomes in eyes with central retinal vein occlusion.

METHODS

This is a retrospective longitudinal cohort study of consecutive patients with acute, treatment-naive central retinal vein occlusion diagnosed between 2009 and 2021 who had at least 12 months of follow-up. Clinical characteristics, treatment patterns, and outcomes were analyzed between eyes stratified based on the presence or absence of a complete posterior vitreous detachment (PVD) on optical coherence tomography at presentation.

RESULTS

Of 102 acute, treatment-naive central retinal vein occlusions identified, 52 (51%) had complete PVD at presentation and 50 (49%) did not. Central subfield thickness was significantly lower in those with complete PVD (12 months: 284.9 ± 122.9 µ m vs. 426.8 ± 286.4 µ m, P < 0.001; last follow-up: 278 ± 127.9 vs. 372.8 ± 191.0 µ m, P = 0.022). One-year intravitreal injection burden was significantly less for those with a complete PVD than those without (5.1 ± 3.6 injections vs. 6.7 ± 3.3 injections, P = 0.013).

CONCLUSION

Central retinal vein occlusion with complete PVD on presentation had significantly lower central subfield thickness and 1-year injection burden. Assessment of the vitreomacular interface in central retinal vein occlusion may serve as a prognostic imaging biomarker.

Two-port dry vitrectomy for rhegmatogenous retinal detachment: a pilot study

OBJECTIVE

To evaluate the safety and efficacy of a new surgical technique for the management of primary rhegmatogenous retinal detachment (RRD), consisting of localized PPV near the retinal break(s), without infusion line, associated with a drainage of subretinal fluid and cryoretinopexy.

METHODS

Multicentric prospective study conducted at the University Hospital of Cagliari and IRCCS Fondazione Policlinico Universitario A. Gemelli, Roma. Twenty eyes affected by RRD with the causative retinal break(s) in the superior meridians were enrolled between February 2022 and June 2022. Patients with cataract ≥3, aphakia, significant posterior capsule opacification, giant retinal tears, retinal dialysis, history of trauma and PVR ≥C2 were excluded. All eyes underwent a two-port 25-gauge PPV with localized removal of the vitreous surrounding retinal break(s), followed by 20% SF6 injection and cryopexy. The surgical time was recorded for each procedure. Best-corrected visual acuity (BCVA) was measured at baseline and postoperative 6 months.

RESULTS

Primary anatomic success at 6 months was achieved by 85% of patients. No complications occurred, except for three (15%) retinal re-detachments. The average surgical time was 8.61 ± 2.16 min. Overall, the difference between pre- and last postoperative mean BCVA was statistically significant (p = 0.02).

CONCLUSIONS

Two-port dry PPV demonstrated safety and efficacy for the treatment of RRD, reaching an 85% of anatomical success rate. Although further studies are necessary to confirm the efficacy and long-term benefit of this treatment, we believe that this surgical technique could be considered a valid and safe alternative for the management of primary RRD.

Eyewatch adjustable drainage device in vitrectomized eyes with refractory glaucoma

BACKGROUND

To describe the efficacy and safety of the adjustable system eyeWatch in vitrectomized glacomatous eyes.

METHODS

Prospective, non-comparative, small case series of 2 patients who underwent glaucoma drainage device implant with the eyeWatch system. Intraocular pressure, number of medications and early and late complications were evaluated.

RESULTS

None of the operated eyes developed early or late complications. After 1 week post operatively, the IOP raised at 28 mmHg in the first eye and 25 mmHg in the second one. The eyeWatch Pen was used to open and set the device into position 3 (that means implant half opened) After waiting for 30 min, IOP was 15 mmHg and 11 mmHg, respectively. Thirty days after surgery we set the EyeWatch into position 0 (that means implant full opened) even though the IOP was under control. A new IOP measurement was done and we registered that IOP was 14 mmHg and 10 mmHg respectively, and it remained stable after six months of follow up.

CONCLUSION

In conclusion, in our case series the use of eyeWatch adjustable system allows a safe and gradual regulation of the flow during post-operative management also in vitrectomized eyes. Considering the percentage of hypotony related complications in vitrectomized eyes this system is an effective and safe technique to handle glaucoma in post vitreoretinal surgery eyes.

Protecting the Eye Lens from Oxidative Stress through Oxygen Regulation

Molecular oxygen is a primary oxidant that is involved in the formation of active oxygen species and in the oxidation of lipids and proteins. Thus, controlling oxygen partial pressure (concentration) in the human organism, tissues, and organs can be the first step in protecting them against oxidative stress. However, it is not an easy task because oxygen is necessary for ATP synthesis by mitochondria and in many biochemical reactions taking place in all cells in the human body. Moreover, the blood circulatory system delivers oxygen to all parts of the body. The eye lens seems to be the only organ that is protected from the oxidative stress through the regulation of oxygen partial pressure. The basic mechanism that developed during evolution to protect the eye lens against oxidative damage is based on the maintenance of a very low concentration of oxygen within the lens. This antioxidant mechanism is supported by the resistance of both the lipid components of the lens membrane and cytosolic proteins to oxidation. Any disturbance, continuous or acute, in the working of this mechanism increases the oxygen concentration, in effect causing cataract development. Here, we describe the biophysical basis of the mechanism and its correlation with lens transparency.

A Population-Based Analysis of Long-Term Costs and Adverse Events after Pneumatic Retinopexy and Pars Plana Vitrectomy

PURPOSE

To comprehensively examine the cost effectiveness, reattachment rate, and complications of pneumatic retinopexy (PnR) compared with pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD) within a universal health care system.

DESIGN

Population-based, multicenter, consecutive, retrospective longitudinal cohort analysis.

SUBJECTS

We identified consecutive adults aged ≥ 50 years requiring surgery for primary RRD over a 20-year interval between April 1, 2002, and March 31, 2022. Initial surgery was considered the index date for analyses.

INTERVENTION

Pneumatic retinopexy was compared with PPV in all analyses.

MAIN OUTCOME MEASURES

The primary analysis investigated the mean annualized health care costs comparing PnR to PPV over the 2 years after initial surgery. Secondary analyses examined the primary reattachment rate and complications.

RESULTS

In total, 25 665 eligible patients were identified, with 8794 undergoing PnR and 16 871 undergoing PPV. The mean patient age was 65 years and 39% were women. The mean annualized cost after PnR was $8924 and $11 937 after PPV (mean difference, $3013; 95% confidence interval, $2533-$3493; P < 0.001). The primary reattachment rate at 90 days after PnR was 83% and after PPV was 93% (P < 0.001). The risk of cataract or glaucoma surgery was lower after PnR, and the frequency of ophthalmology clinic visits, intravitreal injections, and anxiety was higher after PnR. Hospitalizations and long-term disability were less frequent after PnR.

CONCLUSIONS

Pneumatic retinopexy, when compared with PPV, was associated with lower long-term health care costs. Pneumatic retinopexy appeared to be effective, safe, and inexpensive, thus offering a viable option for improving access to RRD repair in appropriately selected cases.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Glycolysis Aids in Human Lens Epithelial Cells' Adaptation to Hypoxia

Hypoxic environments are known to trigger pathological damage in multiple cellular subtypes. Interestingly, the lens is a naturally hypoxic tissue, with glycolysis serving as its main source of energy. Hypoxia is essential for maintaining the long-term transparency of the lens in addition to avoiding nuclear cataracts. Herein, we explore the complex mechanisms by which lens epithelial cells adapt to hypoxic conditions while maintaining their normal growth and metabolic activity. Our data show that the glycolysis pathway is significantly upregulated during human lens epithelial (HLE) cells exposure to hypoxia. The inhibition of glycolysis under hypoxic conditions incited endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) production in HLE cells, leading to cellular apoptosis. After ATP was replenished, the damage to the cells was not completely recovered, and ER stress, ROS production, and cell apoptosis still occurred. These results suggest that glycolysis not only performs energy metabolism in the process of HLE cells adapting to hypoxia, but also helps them continuously resist cell apoptosis caused by ER stress and ROS production. Furthermore, our proteomic atlas provides possible rescue mechanisms for cellular damage caused by hypoxia.

Comparison of simultaneous vs sequential pars plana vitrectomy and cataract surgery

BACKGROUND

To compare the clinical outcomes of patients undergoing sequential pars plana vitrectomy (PPV) followed by cataract extraction surgery (CE) [PPV/CE], simultaneous PPV and CE (PPV + CE), and sequential CE followed by PPV [CE/PPV].

METHODS

A retrospective observational cohort study of 427 eyes of 404 patients who underwent either sequential or simultaneous PPV and CE surgery between March 2016 and May 2021. Pre-operative and post-operative assessments (up to 2 years of follow-up visits) of uncorrected visual acuity (UCVA), corrected distance visual acuity (CDVA), spherical equivalent (SEQ), and refractive prediction error (RPE) was done. Main outcome measures were both visual (UCVA, CDVA) and refractive (RPE, SEQ).

RESULTS

There was a statistically significant difference in CDVA of the PPV/CE, PPV + CE, CE/PPV groups (logMAR 0.34 ± 0.40, 0.65 ± 0.61, and 0.55 ± 0.60, respectively) at one month postoperatively (POM1) (P < 0.001), and at the POM12 visits (logMAR 0.25 ± 0.34, 0.53 ± 0.68, and 0.44 ± 0.48; P = 0.04). In the subgroup analysis of patients with a diagnosis of either epiretinal membrane or vitreous opacities, there was no statistically significant difference in SEQ (P = 0.09) and RPE (P = 0.13) at the combined 1 month and 3 month visits.

CONCLUSION

Simultaneous PPV and cataract surgery demonstrated similar improvements in visual acuity and refractive outcomes, as well as comparable intraoperative and postoperative complication profiles to sequential surgery.

Cataracts

94 million people are blind or visually impaired globally, and cataract is the most common cause of blindness worldwide. However, most cases of blindness are avoidable. Cataract is associated with decreased quality of life and reduced life expectancy. Most cases of cataract occur after birth and share ageing and oxidative stress as primary causes, although several non-modifiable and modifiable risk factors can accelerate cataract formation. In most patients, phacoemulsification with intraocular lens implantation is the preferred treatment and is highly cost-effective. There has been an increase in the use of comprehensive cataract surgical services, including diagnoses, treatment referrals, and rehabilitation. However, global inequity in surgical service quality is still a limitation. Implementation of preoperative risk assessment, risk reduction strategies, and new surgical technologies have made cataract surgery possible at an earlier stage of cataract severity with the expectation of good refractive outcomes. The main challenge is making the service that is currently available to some patients accessible to all by use of universal health coverage.

Cataract progression following lens-sparing pars plana vitrectomy for rhegmatogenous retinal detachment

Lens-sparing pars plana vitrectomy (PPV) is often followed by cataract development. However, there have been few prospective studies evaluating the timing of cataract progression and potential associated factors. This was an observational study conducted at the Ophthalmology Unit of the University Hospital of Parma (Parma, Italy). Patients presenting with rhegmatogenous retinal detachment (RRD), who underwent PPV with preservation of the lens, were examined according to a scheduled follow-up (3, 6 and 12 months after PPV) and then preoperatively when cataract extraction surgery (CES) was indicated, or at the end of the study follow-up period (May 2021). The primary outcome was the interval between PPV and CES indication (based on predefined refractive criteria). A total of 36 eyes of 36 patients (mean age: 52 ± 10 years) were included in the study. Nineteen eyes (53%) were indicated for CES a median of 14.5 months (IQR: 12.0-24.8) after PPV. The nuclear and posterior subcapsular forms of cataract progressed significantly starting at 6 months after PPV. Older age at the time of PPV, silicone oil tamponade and RRD without macular involvement were significantly and independently associated with an earlier indication for CES. Patient age and the use of silicone oil tamponade must be taken into consideration when evaluating the risk of cataract development after PPV.

25-Gauge pars plana vitrectomy combined with air tamponade for primary rhegmatogenous retinal detachment

OBJECTIVE

This study was performed to evaluate the outcomes of 25-gauge (25-G) pars plana vitrectomy (PPV) with air tamponade for primary rhegmatogenous retinal detachment (RRD).

METHODS

This retrospective consecutive case series included 126 eyes of 125 patients with primary RRD who underwent 25-G PPV with air tamponade. The patients were followed up for at least 6 months following surgery. The main outcome measures were the primary and final anatomical success rates and postoperative complications.

RESULTS

The mean age of the 125 patients (80 men and 45 women) was 53.7 ± 10.0 years. The mean follow-up period was 8.3 ± 2.2 months (range, 6-18 months). Twenty-four eyes (19.0%) presented with high myopia, and 13 eyes (10.3%) were pseudophakic. Of the 126 eyes, 37 (29.4%) had inferior breaks, 2 (1.6%) had choroidal detachment, and 86 (68.3%) had macular detachment. The single- and final-operation success rates were 96.0% and 100%, respectively. Postoperative complications included macular hole formation in two eyes. During follow-up, secondary cataract surgery was performed in 27 (23.9%) of the 113 phakic eyes.

CONCLUSION

25-G PPV with air tamponade is effective and safe in treating selected patients with primary RRD with a high anatomical success rate.

Formulation and Evaluation of Polymer-Based Nanoparticles for Intravitreal Gene-Delivery Applications

The advent of the first-ever retinal gene therapy product, involving subretinal administration of a virus-based gene delivery platform, has garnered hope that this state-of-the-art therapeutic modality may benefit a broad spectrum of patients with diverse retinal disorders. On the other hand, clinical studies have revealed limitations of the applied delivery strategy that may restrict its universal use. To this end, intravitreal administration of synthetic gene-delivery platforms, such as polymer-based nanoparticles (PNPs), has emerged as an attractive alternative to the current mainstay. To achieve success, however, it is imperative that synthetic platforms overcome key biological barriers in human eyes encountered following intravitreal administration, including the vitreous gel and inner limiting membrane (ILM). Here, we introduce a series of experiments, from the fabrication of PNPs to a comprehensive evaluation in relevant experimental models, to determine whether PNPs overcome these barriers and efficiently deliver therapeutic gene payloads to retinal cells. We conclude the article by discussing a few important considerations for successful implementation of the strategy. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Preparation and characterization of PNPs Basic Protocol 2: Evaluation of in vitro transfection efficacy Basic Protocol 3: Evaluation of PNP diffusion in vitreous gel Basic Protocol 4: Ex vivo assessment of PNP penetration within vitreoretinal explant culture Basic Protocol 5: Assessment of in vivo transgene expression mediated by intravitreally administered PNPs.

Intraocular Lens Calculation Using 8 Formulas in Silicone Oil-Filled Eyes Undergoing Silicone Oil Removal and Phacoemulsification After Retinal Detachment

PURPOSE

To evaluate formulas for intraocular lens (IOL) calculation in silicone oil (SO)-filled eyes.

DESIGN

Retrospective, consecutive case series.

METHODS

We conducted our study at the Department of Ophthalmology, Goethe University, Frankfurt, Germany, and included SO-filled eyes that received SO removal combined with phacoemulsification and IOL implantation. Preoperative assessments included biometry (IOLMaster 700; Carl Zeiss Meditec). To evaluate the measurements, we compared the mean prediction error, and mean and median absolute prediction error of 8 different formulas.

RESULTS

A total of 90 eyes matched our inclusion criteria. The median absolute error was lowest in the Barrett Universal II formula (0.43 diopters [D] ± 0.75) followed by Kane (0.44 D ± 0.75), Hill-radial basis function (0.47 D ± 0.74), Holladay II (0.47 D ± 0.77), Sanders Retzlaff Kraff/theoretical (0.51 D ± 0.74), Holladay I (0.51 D ± 0.76), and Haigis and Hoffer Q (0.52 D ± 0.74 each). Regarding eyes within ±0.5 D Barrett Universal II (57.8%, 52 eyes) performed best, again followed by Kane (56.7%, 51 eyes) and Hill-radial basis function (54.4%, 49 eyes).

CONCLUSION

Using modern formulas for IOL calculation in oil-filled eyes improves predictability but still not as good as in unoperated eyes. This issue is created by the change in refractive index due to the SO fill and therefore a lower precision of axial length measurement and effective lens position prediction.

Refractive Outcomes of Combined Cataract Surgery and Vitrectomy Compared to Cataract Surgery Alone

PURPOSE

The aim of the study was to evaluate the refractive outcomes of combined cataract surgery and vitrectomy compared to cataract surgery alone.

METHODS

This retrospective chart review study included two groups: (1) combined surgery in 103 eyes (101 patients) who underwent cataract surgery with posterior chamber intraocular lens (PCIOL) placement by a single cataract surgeon and vitrectomy by a single vitreoretinal surgeon at the same surgical setting; (2) cataract surgery alone by the same surgeon in 107 eyes (84 patients). Refractive outcomes and complications between the combined and cataract surgery alone group were compared. The predicted refractive error was compared to postoperative refractive outcomes in both groups, surgically induced astigmatism (SIA), intraoperative or postoperative complications of either cataract surgery or vitrectomy, and cystoid macular edema.

RESULTS

There was no statistically significant difference between predicted and actual postoperative refractive outcomes between the combined and cataract surgery alone groups (within ±0.5 diopters [D], p = 0.099; within ±1.0 D, p = 0.721). There was no difference in SIA refractive outcomes between the two groups (p = 0.509). The use of intraoperative gas for retina tamponade did not significantly affect postoperative refractive outcomes. Both cataract surgery and vitrectomy were successfully performed without unexpected complications from either procedure affecting the other.

DISCUSSION/CONCLUSION

Combined cataract surgery and vitrectomy allows excellent refractive outcomes equal to cataract surgery alone, allowing each procedure to be performed independently by separate anterior and posterior segment surgeons. Combined procedures can be performed in eyes with a variety of retinal indications and can include fluid-gas exchange with minimal risk of PCIOL malposition or change in targeted refraction.

The Postvitrectomy Cataract

To review the recent literature regarding risk factors for cataract formation after vitrectomy, the challenges and management strategies for anterior segment surgeons when facing post-vitrectomy cataract surgery, and the visual outcomes of patients undergoing post-vitrectomy cataract surgery. Cataract surgery after vitrectomy can be safely performed to significantly improve the visual outcome in most post-vitrectomy patients, although final visual acuity is primarily limited by the patient’s underlying vitreoretinal pathology.

Predicting speed of progression of lens opacification after pars plana vitrectomy with silicone oil

Purpose

An increasing number of posterior segment disorders is routinely managed with pars plana vitrectomy (PPV). In older, phakic patients cataract formation is expected within the first two years after surgery. For younger patients its progression is individually fluctuating. This study uses an objective quantitative measurement for lens-status-monitoring after PPV with silicone oil to derive predictions for progression and severity of post-operative lens opacification evaluated in patients with rhegmatogenous retinal detachment (RRD).

Methods

Data acquisition was performed prospectively between March 2018 and March 2021. PentacamHR® Nucleus Staging mode (PNS) was used to objectively gather data about nuclear cataracts after PPV at different time points. Data was grouped into training and test sets for a mathematical prediction model. Via backward variable selection method a mathematical formula was set up by means of which predictions about lens densitometry (LD) can be calculated.

Results

20 males [58.8%] and 14 females [41.2%] matched the inclusion criteria (mean age 50.6 years [23–75; ±12.3]). Average follow-up was 8.1 months (3,4–17.4; ±3.4). Mean baseline LD of the treated and fellow eye before surgery was 11.1% (7.7%-17.6%; ±2.0) and 11.2% (7.7%-14.8%; ±1.5), respectively. Predicted LD values by the model for five pre-selected patients closely match the observed data with an average deviation of 1.06%.

Conclusions

Using an objective parameter like LD delivered by the PentacamHR® PNS mode additionally to the patient’s age allows us to make an individual prediction for any time after PPV with silicone oil due to RRD for all ages. The accuracy of the model was stronger influenced by baseline LD as cofactor in the equation than patient’s age. The application for the prediction lens opacification [which can be accessed for free under the following link (https://statisticarium.com/apps/sample-apps/LensDensityOil/)] can help vitreoretinal surgeons for patient consultation on the possibility to combine PPV with cataract surgery.

Pars Plana Ahmed Valve Implantation for Vitrectomized Eyes With Refractory Glaucoma

This study aimed to analyze the surgical outcomes of pars plana Ahmed valve implantation in vitrectomized eyes with refractory glaucoma. We performed a retrospective case review of consecutive patients with refractory glaucoma after undergoing pars plana vitrectomy who underwent pars plana Ahmed valve implantation between July 2019 and December 2020 at the glaucoma unit of the Affiliated Changshu Hospital of Xuzhou Medical University (Changshu, China). All the patients were followed up for ≥12 months postoperatively. We recorded pre- to postoperative changes in best-corrected visual acuity (BCVA), intraocular pressure (IOP), number of anti-glaucoma medication, corneal endothelial count, and surgical complications, if any. There was a significant improvement in the median BCVA from 2.30 (0.87, 2.30) logMAR preoperatively to 1.70 (0.70, 2.30) logMAR at discharge and 1.0 (0.52, 1.85) at final examination (p = 0.011, p = 0.001). Compared with the preoperative IOP level, there was a significant decrease in the postoperative IOP at each postoperative time point (p < 0.001). There was a significant reduction in the median number of anti-glaucoma drugs (including postoperative ocular massage), from 3.00 (2.00, 3.00) preoperatively to 0.00 (0.00, 1.00) at the last follow-up postoperative examination (p < 0.001). A 29-year-old woman with proliferative diabetic retinopathy who underwent surgical treatment at 5 months postoperatively for fibrous wrapping formed around the plate of the Ahmed valve showed an IOP of 14 mmHg at the last follow-up. Our findings indicated that pars plana Ahmed valve implantation can be safely performed for managing vitrectomized eyes with refractory glaucoma.

Rhegmatogenous retinal detachment repair-does age, sex, and lens status make a difference?

PURPOSE

To analyze the correlation between lens status, age, and sex in the epidemiology and success rates of rhegmatogenous retinal detachment (RRD) surgery.

METHODS

The files of all consecutive patients undergoing vitreoretinal surgery for uncomplicated RRD between Jan 2005 und Dec 2020 were retrospectively reviewed. Successful outcome was defined as no retinal redetachment occurring within 3 months after surgery.

RESULTS

5502 eyes with uncomplicated primary RRD were included. Mean age of the patients was 61.1 years (± 13.6 SD). In the age group over 40 years, a male predominance was found. The percentage of pseudophakic RRD increased from 25 to 40% during the 15 years observation period. In the age group 50 to 69 years, patients with pseudophakic detachments were male in 786 out of 1079 cases (72.9%). In the same age group, 1285 of 2110 (60.9%) patients with phakic RRD were male. Overall, primary success rate after one procedure was 91.2% (5018 of 5502). In the phakic eyes, the primary success rate was higher in those eyes that underwent combined phacovitrectomy (93.0%), compared to those without simultaneous cataract surgery (88.7%; p = 0.002).

CONCLUSION

The ratio of male and female patients with RRD varies between age groups. The proportion of pseudophakic RRD has increased within 15 years. The male predominance in RRD is stronger in pseudophakic than in phakic eyes. In phakic eyes with RRD, a combined phacovitrectomy yielded better anatomical results.

The influence of retinal oxygen saturation and choroidal volume on postoperative outcomes in patients with epiretinal membrane

Purpose

To investigate the effects of vitrectomy (Vy) with or without same time cataract surgery and membrane plus internal limiting membrane peeling (MP+ILMP) on retinal oxygenation and choroidal volume and their role on postoperative outcome.

Methods

Thirty‐two eyes were included in this prospective clinical study. All patients received 23 gauge Vy+MP+ILMP without endotamponade. Additional cataract surgery was performed in 14 patients. Follow‐up visits were scheduled at day 1, week 1, month 1 and month 3. At each visit, best corrected visual acuity (BCVA) using ETDRS charts (except at day 1), oxygenation of retinal vessels using the Oxymap T1, and optical coherence tomography (OCT, Heidelberg Spectralis) was performed.

Results

Mean BCVA increased significantly from 73 ± 11 letters to 77 ± 7 letters at month 3 (p = 0.02). Mean central retinal thickness (CRT) decreased from 456 ± 84 µm at baseline to 418±58µm (p = 0.01 baseline versus month 3). In the cataract surgery group, CRT was higher at month 3 than in the group without (400 ± 58 µm versus 441 ± 51 µm; p = 0.007). There was no statistically significant difference in choroidal volume or oxygenation of retinal vessels between groups (additional cataract surgery versus vitrectomy alone). Oxygenation of retinal arteries tended to decrease at day 1 followed by an increase, but the changes did not reach the level of significance (p = 0.29 baseline versus month 3). Oxygenation of retinal veins increased significantly (p = 0.02 baseline versus month 1; p = 0.04 baseline versus month 3, accordingly). There was a significant negative correlation (Spearman correlation coefficient rs = −0.35, p = 0.047) between visual acuity and oxygenation of retinal veins at month 3. No statistically significant correlation was found between CRT and oxygenation of neither retinal arteries nor veins. Choroidal volume (CV) of the central mm did not change significantly during the study period (baseline: 0.203 ± 0.04 mm³, median: 0.206, month 3: 0.205 ± 0.04 mm³, p = 0.54). There was no statistically significant effect of choroidal volume at baseline on postoperative clinical outcomes (change in BCVA estimate [95% CI]: 7 [−76; 90], p = 0.86; change in CRT: 147 [−577; 871], p = 0.68).

Conclusion

Oxygen saturation may affect the visual acuity outcome but not the CRT in patients after vitrectomy for epiretinal membrane. Choroidal thickness had no statistically significant influence on the study outcomes. Further studies are needed to evaluate if the measurement of retinal oxygenation may be helpful in the decision for surgery.

Laser-induced nanobubbles safely ablate vitreous opacities in vivo

In myopia, diabetes and ageing, fibrous vitreous liquefaction and degeneration is associated with the formation of opacities inside the vitreous body that cast shadows on the retina, appearing as 'floaters' to the patient. Vitreous opacities degrade contrast sensitivity function and can cause notable impairment in vision-related quality of life. Here we introduce 'nanobubble ablation' for safe destruction of vitreous opacities. Following intravitreal injection, hyaluronic acid-coated gold nanoparticles and indocyanine green, which is widely used as a dye in vitreoretinal surgery, spontaneously accumulate on collagenous vitreous opacities in the eyes of rabbits. Applying nanosecond laser pulses generates vapour nanobubbles that mechanically destroy the opacities in rabbit eyes and in patient specimens. Nanobubble ablation might offer a safe and efficient treatment to millions of patients suffering from debilitating vitreous opacities and paves the way for a highly safe use of pulsed lasers in the posterior segment of the eye.

Air Tamponade for Rhegmatogenous Retinal Detachment With Inferior Breaks After 25-Gauge Pars Plana Vitrectomy: Technique and Outcome

To evaluate the outcomes of 25-guage (G) pars plana vitrectomy (PPV) with air tamponade for rhegmatogenous retinal detachment (RRD) with inferior breaks. This retrospective consecutive case series included fifty-two eyes of fifty-two RRD patients with inferior breaks who underwent 25-G PPV with air tamponade. These patients were followed up for at least 6 months following surgery. Primary and final anatomical success rates and postoperative complications were the main outcome measures. The mean age of the patients (39 men and 13 women) was 51.8 ± 11.8 years. There were 49 primary RRDs (94.2%) and three recurrent RRDs (5.8%). The mean follow-up period was 8.2 ± 1.6 months (range: 6–13 months). Sixteen eyes (30.8%) presented with high myopia, and six eyes (11.5%) were pseudophakic. Proliferative vitreous retinopathy grade was C1 in four eyes (7.7%). Of the 52 eyes, two (3.8%) were complicated with choroidal detachment, and forty (76.9%) had the macula detached. The single- and final-operation success rates were 96.2% and 100%, respectively. During follow-up, secondary cataract surgery was performed in eight eyes (17.4%) of the 46 phakic eyes. 25-G PPV with air tamponade is effective in treating selected RRD patients with inferior breaks. Patients can benefit from early visual recovery and less complications.

Erworbene Katarakte

Weitaus seltener und daher weniger bekannt als die altersbedingte Katarakt ist die sekundär erworbene Katarakt, die eine diagnostische und chirurgische Herausforderung darstellen kann. Dieser Beitrag gibt einen Überblick über die häufigsten Subtypen vor allem bei Erwachsenen und beleuchtet die chirurgischen Besonderheiten einschließlich perioperativer Charakteristika.

Erworbene Katarakte

Weitaus seltener und daher weniger bekannt als die altersbedingte Katarakt ist die sekundär erworbene Katarakt, die eine diagnostische und chirurgische Herausforderung darstellen kann. Dieser Beitrag gibt einen Überblick über die häufigsten Subtypen vor allem bei Erwachsenen und beleuchtet die chirurgischen Besonderheiten einschließlich perioperativer Charakteristika.

Retinal Detachment Repair With Vitrectomy: Air Tamponade Integration to a Vitreoretinal Service, Comparison With Gas Tamponade, and Literature Review

BACKGROUND AND OBJECTIVE

Rhegmatogenous retinal detachment (RRD) repair by pars plana vitrectomy and gas tamponade (GT) has significant clinical and quality-of-life impacts compared with repair by short-acting air tamponade (AT). With AT, most authors minimize cryotherapy because of prolonged chorioretinal scar formation and use perfluorocarbon to maximize subretinal fluid drainage; this deviates from traditional technique, which discourages popularization of AT.

PATIENTS AND METHODS

Prospective 12-month study from January to December 2019 of all primary macula-on RRD cases. Patients fulfilling the inclusion criteria for the Pneumatic Retinopexy Versus Vitrectomy for Retinal Detachment Trial received AT and otherwise were assigned to receive GT.

RESULTS

Forty-six patients were enrolled: 22 (48%) receiving AT and 24 (52%) receiving GT. The primary success rate of AT was 21 (95%) and the primary success rate of GT was 23 (96%), with 100% final success. Cryopexy was used in 64% of AT cases and 58% of GT cases. Cataract surgery was required less when AT was used (1 [6%]) than when GT was used (3 [21%]). AT was used in 48% of primary macula-on RRD and 27% of all primary RRD cases.

CONCLUSIONS

AT has visual and anatomical outcomes comparable to those of GT with conventional vitrectomy techniques, with faster postoperative rehabilitation enabling a swift return to normal daily activities. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:87-95.].

Possible roles of anti-type II collagen antibody and innate immunity in the development and progression of diabetic retinopathy

The pathogenesis of both diabetic retinopathy (DR) and rheumatoid arthritis (RA) has recently been considered to involve autoimmunity. Serum and synovial fluid levels of anti-type II collagen antibodies increase early after the onset of RA, thus inducing immune responses and subsequent hydrarthrosis and angiogenesis, which resemble diabetic macular edema and proliferative DR (PDR), respectively. We previously reported that DR is also associated with increased serum levels of anti-type II collagen antibodies. Retinal hypoxia in DR may induce pericytes to express type II collagen, resulting in autoantibody production against type II collagen. As the result of blood-retinal barrier disruption, anti-type II collagen antibodies in the serum come into contact with type II collagen around the retinal vessels. A continued loss of pericytes and type II collagen around the retinal vessels may result in a shift of the immune reaction site from the retina to the vitreous. It has been reported that anti-inflammatory M2 macrophages increased in the vitreous of PDR patients, accompanied by the activation of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a key regulator of innate immunity. M2 macrophages promote angiogenesis and fibrosis, which might be exacerbated and prolonged by dysregulated innate immunity.

Two-year Changes in Postoperative Central Macular Thickness and Subfoveal Choroidal Thickness in Epiretinal Membrane Patients

Purpose: To evaluate changes in central macular thickness (CMT) and subfoveal choroidal thickness (SFCT) after phacovitrectomy over a 2-year period in idiopathic epiretinal membrane (ERM) patients.Methods: The records of 52 idiopathic ERM patients (52 eyes) who underwent phacovitrectomy, without recurrence of the condition over a 2-year follow-up period, were reviewed retrospectively. Changes in CMT and SFCT, as measured by optical coherence tomography, were analyzed and compared with those of a normal control group over a 2-year period.Results: The mean preoperative CMT and SFCT were 425.67 ± 84.67 and 257.56 ± 90.13 μm, respectively. Postoperative CMT was reduced significantly to 372.17 ± 45.26 μm at 1 year and 363.15 ± 47.35 μm at 2 years (p < 0.001). SFCT at 1 and 2 years postoperatively was significantly reduced to 238.85 ± 84.85 and 230.31 ± 87.95 μm, respectively (p < 0.001). In the control group, there was no significant change in CMT; however, the SFCT decreased by 11.09 ± 22.36 μm during the 2-year follow-up (p = 0.007). In contrast, in the patient group, CMT and SFCT decreased by 62.52 ± 71.45 and 27.25 ± 41.97 μm, respectively, showing a significant difference from the control group (p < 0.001 and p = 0.043, respectively). Both before surgery and at 1 year postoperatively, the thinner the CMT, the better the best-corrected visual acuity (BCVA) (p = 0.010 and p = 0.018, respectively). A better postoperative BCVA at 2 years was associated with a thinner CMT and better BCVA before surgery (p < 0.001 and p < 0.001, respectively).Conclusions: Following a phacovitrectomy procedure, ERM patients showed significant reductions in both the CMT and SFCT at the 2-year follow-up.

Rapid progression of chorioretinal atrophy in punctate inner choroiditis: a case report

Background

The chorioretinal inflammatory lesions occurring in punctate inner choroiditis evolve into punched-out atrophic scars. Typically, the progression is gradual. We report a case of highly myopic punctate inner choroiditis with rapid progression of chorioretinal atrophy.

Case presentation

A 48-year-old Japanese woman with high myopia presented with decreased visual acuity. Best-corrected visual acuity was 20/28 in the right eye and 20/16 in the left eye; axial length was 29.0 mm and 28.7 mm, respectively. Fundoscopy revealed an epiretinal membrane in the left eye. Three years later, the best-corrected visual acuity in the left eye had decreased to 20/33; at this time, the patient underwent vitrectomy with epiretinal membrane and internal limiting membrane peeling in this eye. Six months later, the best-corrected visual acuity in the left eye decreased suddenly to 20/100. Optical coherence tomography showed a nodule-like lesion in the outer retina with disruption of the retinal pigment epithelium and a focally thickened choroid, compatible with PIC. One month later, the choroidal thickness had decreased. The central chorioretinal atrophy expanded rapidly at a rate of 0.45 mm²/year over the next 3 years, and new areas of patchy focal chorioretinal atrophy developed in the perifovea.

Conclusions

Rapid progression of chorioretinal atrophy was observed in a patient with punctate inner choroiditis. Because punctate inner choroiditis is often associated with degenerative myopia, the retina is fragile and may be susceptible to mechanical damage. This case report alerts clinicians to the need for careful management of patients with punctate inner choroiditis, especially after vitrectomy.

Safety and effectiveness of an iris hook assisted phacoemulsification in vitrectomized eyes

AIM

To introduce a simple iris hook assisted phacoemulsification (PE) procedure and evaluate the safety and efficacy of it in completely vitrectomized eyes.

METHODS

A single centre study which included 65 previously completely vitrectomized eyes of 62 patients who underwent cataract surgery. Patients were randomly divided into 3 groups. Patients received PE, and intraocular lens (IOL) implantation with the assistance of iris hook (Synergeties™) as group A (25 eyes); patients who received PE assisted with a 25G pars plana irrigation as group B (20 eyes), and patients who received PE performed without the help of any instrument as group C (20 eyes). Main outcome measures were surgery duration, Ultrasound (U/S) total time, endothelial cell density (ECD), cumulative dissipated energy (CDE) and complications of the procedures.

RESULTS

With the help of iris hook, the patients in group A had the lowest ECD loss rate (0.07±0.03, 0.09±0.03, and 0.10±0.03, P<0.05), shortest CDE (12.2±4.1, 15.8±6.0, and 16.0±6.0, P<0.05) and U/S total time (36.6±13.0s, 46.3±16.4s, and 47.6±16.1s, P<0.05), and minimal incidence of complications. The longest surgery duration was in group B (19.4±1.6min) and maximum complications rate in group C (20% miosis, 10% posterior capsular tears, 5% zonular dialysis, 5% cystoid macular edema). While best-corrected visual acuity (BCVA), intraocular pressure (IOP) and ECD did not show a significant difference among the three groups.

CONCLUSION

Without prolonged surgery duration, the iris hook assistant method can minimize heat generation during surgery and incidence of complications, which transfer the challenged PE in vitrectomized eyes into a regular surgery. It does not need any change in the hydrodynamic parameters and in the bag PE technique, easy to operate even for junior surgeons.

An objective evaluation of lens transparency after vitrectomy surgery with different intravitreal tamponades

PURPOSE

To evaluate and compare the effects of different intraocular tamponade agents on lens density after vitrectomy.

METHODS

The participating patients were divided into four groups according to the tamponade agent used: a sulfur hexafluoride (SF₆) group, a perfluoropropane (C₃F₈) group, a silicone oil group, and a no tamponade group. Lens density measurements were performed preoperatively and two weeks, one month, and three months postoperatively using a Pentacam HR device with a Scheimpflug camera. The postoperative values were compared with the preoperative baseline values, also the values were compared between the four groups.

RESULTS

The study included 82 eyes (82 patients). In the SF₆ group, lens density significantly increased in all zones two weeks and one and three months postoperatively (all P < .05). In the C₃F₈ group, lens density significantly increased in all zones three months postoperatively (all P < .01). In the silicone oil group, the zone 1, zone 2, and average lens density (ALD) value significantly increased one and three months postoperatively (all P < .05). In the no tamponade group, the zone 1, zone 2, and ALD values significantly increased three months postoperatively (all P < .05). There were no significant differences between the four groups in any zone either preoperatively or postoperatively (all P > .05).

CONCLUSIONS

Although increases in lens density were observed earlier in the tamponade groups than in the no tamponade group, between the groups over the follow-up period were no differences. We need the development of new surgical methods and materials to prevent post-vitrectomy lens damage in the future.

Current and novel multi-imaging modalities to assess retinal oxygenation and blood flow

Retinal ischemia characterizes the underlying pathology in a multitude of retinal diseases that can ultimately lead to vision loss. A variety of novel imaging modalities have been developed to characterize retinal ischemia by measuring retinal oxygenation and blood flow in-vivo. These technologies offer valuable insight into the earliest pathophysiologic changes within the retina and provide physicians and researchers with new diagnostic and monitoring capabilities. Future retinal imaging technologies with the capability to provide affordable, noninvasive, and comprehensive data on oxygen saturation, vasculature, and blood flow mechanics are needed. This review will highlight current and future trends in multimodal imaging to assess retinal blood flow and oxygenation.

Radiotherapy-induced alterations in vitreous humor: A new potential critical structure

Vitreous humor (VH) is not considered as a critical structure in the radiotherapy planning process. In the present study, an experimental animal model was performed to examine the effects of radiotherapy on VH. The right eyes of twelve New Zealand rabbits were irradiated to 60 Gy in 3 fractions in accordance with the scheme used in the treatment of uveal melanoma in our clinic, and contralateral (left) eyes were considered as control. Weekly ophthalmologic examination was performed after irradiation, for three months. At the end of the third month, enucleation and vitreous collection were conducted. The vitreous samples were subjected to metabolomic analyses, ELISA analyses, viscosity measurements, and electron microscopic examination. In control and experimental vitreous samples, 275 different metabolites were identified, and 34 were found to differ significantly between groups. In multivariate analyzes, a clear distinction was observed between control and irradiated vitreous samples. Pathway analysis revealed that nine pathways were affected, and these pathways were mainly related to amino acid metabolism. A significant decrease was observed in the expressions of type II, V, and XI collagens in protein level in the ELISA. There was a non-significant decrease in type IX collagen and viscosity. Electron microscopic examination revealed disrupted collagen fibrillar ultra-structure and dispersed collagen fragments in the experimental vitreous. An intact vitreous is essential for a healthy eye. In this study, we observed that radiation causes changes in the vitreous that may have long-term consequences.

Vitreous function and intervention of it with vitrectomy and other modalities

The vitreous body, the largest intraocular component, plays a key role in eye development, refraction, cell barrier function, oxygen metabolism and the pathogenesis of assorted diseases. Age, refraction and systemic diseases can cause vitreous metabolic abnormalities. With the continuous development of vitrectomy techniques and equipment, vitreous injections and vitrectomies have increased over the recent decades. However, the normal oxygen tension gradient in the vitreous helps to protect the lens and anterior chamber angle from oxidative stress damage, whereas the increased vitreous oxygen tension around lens and the trabecular meshwork after vitrectomy may lead to postoperative nuclear cataract and a high incidence of open angle glaucoma. As a conventional procedure, scleral buckling holds several advantages over vitrectomy in selected cases. This review raises concerns regarding the function of the vitreous, and encourages conducting vitreous interventions prudently.