Surgical Technique to Treat Presbyopic Inlay-Associated Corneal Haze With Sequential Excimer Photoablation: A Case Series.

PURPOSE: To describe an approach using sequential excimer laser ablation of the stromal surface of the corneal flap with or without subsequent excimer ablation to the stromal bed to reduce presbyopic inlay-associated corneal haze. METHODS: Twelve patients who underwent KAMRA inlay (Acufocus) explantation due to corneal haze were included. The mean interval between explantation and the primary surgery (phototherapeutic keratotomy [PTK] to corneal flap) was 16.2 ± 29.7 months (range = 1 to 83 months). The corneal flap was lifted and laid on an evisceration spoon and an excimer laser was used to ablate the flap stroma by 30 to 40 µm depth. Subsequently, an excimer laser was used to ablate and treat the stromal bed following a second flap lift according to the manifest refraction, leaving a minimal residual stromal bed thickness of greater than 300 µm. For both procedures, mitomycin C 0.02% was applied to the stromal bed before the flap was replaced and a bandage contact lens applied. RESULTS: Reductions in corneal haze were observed, following PTK to the corneal flap with or without photorefractive keratectomy (PRK) to the stromal bed, both clinically and on imaging. No significant changes in uncorrected distance visual acuity (P = .442) and corrected distance visual acuity (P = .565) were observed. Improvements were observed for both spherical equivalent refractive errors (P = .036) and corneal light backscatter (P = .019). There were significant improvements in spherical aberrations (P = .014) but no changes in total lower and higher order aberrations. CONCLUSIONS: PTK to the corneal flap with or without subsequent stromal bed PRK is an effective technique in treating corneal haze following presbyopic inlay explantation. [J Refract Surg. 2023;39(9):639-646.].

Six-year incidence of age-related macular degeneration and correlation to OCT-derived drusen volume measurements in a Chinese population.

AIMS: To report the 6-year incidence of optical coherence tomography (OCT)-derived age-related changes in drusen volume and related systemic and ocular associations. METHODS: Chinese adults aged 40 years and older were assessed at baseline and 6 years with colour fundus photography (CFP) and spectral domain (SD) OCT. CFPs were graded for age-related macular degeneration (AMD) features and drusen volume was generated using commercially available automated software. RESULTS: A total of 4172 eyes of 2580 participants (mean age 58.12±9.03 years; 51.12% women) had baseline and 6-year follow-up CFP for grading, of these, 2130 eyes of 1305 participants had gradable SD-OCT images, available for analysis. Based on CFP grading, 136 (3.39%) participants developed incident early AMD and 10 (0.25%) late AMD. Concurrently, retinal pigment epithelial-Bruch's membrane (RPE-BrC) volumes decreased, remained stable and increased in 6.8%, 78.5% and 14.7%, respectively, over 6 years. In eyes where RPE-BrC volumes were >0 mm3 at baseline, this was associated with two-fold higher prevalence rate of any AMD at baseline (p<0.001). Multivariable analysis showed that when compared with eyes where RPE-BrC volume was unchanged, volume decrease was significantly associated with older age (OR=1.30; p<0.001), smoking (OR=2.21; p=0.001) and chronic kidney disease (OR=3.4, p=0.008), while increase was associated with older age (OR=1.36; p<0.001) and hypertension (OR=1.43; p=0.016). CONCLUSION: AMD incidence detected at 6 years on CFP and correlated OCT-derived drusen volume measurement change is low. Older age and some systemic risk factors are associated with drusen volume change, and our data provide new insights into relationship between systemic risk factors and outer retinal morphology in Asian eyes.

Clinical operational considerations and responses to lockdown and reopening in the Covid-19 pandemic: experience of a tertiary ophthalmology centre in Singapore.

BACKGROUND: Much has been written on infection control and clinical measures for ophthalmic institutions and departments to cope with the COVID-19 pandemic. However, few articles have detailed implementation plans to manage lockdowns and subsequent re-openings. In this article, specific operational responses and their outcomes in a large tertiary ophthalmology centre are described. METHOD: Through a concerted effort led by a dedicated task force, the Singapore National Eye Centre (SNEC) planned and executed an operational transformation to respond to the restrictions imposed on healthcare delivery during a national lock down. A carefully calibrated re-starting of services was carried out with the subsequent phased reopening of the country, taking into consideration unique constraints faced at that time. Strategies for operating in the new normal environment were also developed. RESULTS: Outpatient attendances were safely and expediently reduced by 70% (8749 vs. 29,311) and 82% (5164 vs. 29,342) in April and May 2020, respectively, compared to the corresponding months in 2019. A correspondingly large reduction in surgical load was also achieved through a similar triaging and prioritization system. Through optimizing the center's use of space and time, as well as expanding on new models of care, a return to pre-pandemic patient load was achieved 3 months into the phased reopening of the country, and subsequently exceeded in the following months. CONCLUSION: The lessons gleaned from SNEC's experience may be useful for institutions currently facing the same challenges, and for future responses to COVID-19 resurgences or other pandemics.

Evolving treatment paradigms for PCV.

Polypoidal choroidal vasculopathy (PCV) is a subtype of neovascular AMD (nAMD) that accounts for a significant proportion of nAMD cases worldwide, and particularly in Asia. Contemporary PCV treatment strategies have closely followed those used in typical nAMD, though there are significant gaps in knowledge on PCV management and it remains unclear if these strategies are appropriate. Current clinical trial data suggest intravitreal anti-vascular endothelial growth factor (VEGF) therapy alone or in combination with photodynamic therapy is effective in managing haemorrhage and exudation in PCV, although the optimal treatment interval, including as-needed and treat-and-extend approaches, is unclear. Newer imaging modalities, including OCT angiography and high-resolution spectral domain OCT have enabled characterisation of unique PCV biomarkers that may provide guidance on how and when treatment and re-treatment should be initiated. Treatment burden for PCV is a major focus of future therapeutic research and several newly developed anti-VEGF agents, including brolucizumab, faricimab, and new modes of drug delivery like the port delivery system, offer hope for dramatically reduced treatment burden for PCV patients. Beyond anti-VEGF therapy, recent developments in our understanding of PCV pathophysiology, in particular the role of choroidal anatomy and lipid mediators in PCV pathogenesis, offer new treatment avenues that may become clinically relevant in the future. This article explores the current management of PCV and more recent approaches to PCV treatment based on an improved understanding of this unique disease process.

Real-world cost-effectiveness of anti-VEGF monotherapy and combination therapy for the treatment of polypoidal choroidal vasculopathy.

OBJECTIVES: For patients with polypoidal choroidal vasculopathy (PCV), intravitreal anti-vascular endothelial growth factor (anti-VEGF) combination therapy has been shown to be cost-saving relative to monotherapy in a clinical trial setting. However, whether this also applies to real-world settings is unclear. We aim to compare the real-world functional outcomes and cost-effectiveness of intravitreal anti-VEGF combination therapy relative to monotherapy, to investigate whether combination therapy is truly cost-saving. METHODS: We used a Markov model to simulate a hypothetical cohort of PCV patients treated at Singapore National Eye Centre. Model parameters were informed by coarsened exact matched estimates of a two-year retrospective study of patients who initiated treatment in 2015. Treatment options included intravitreal aflibercept, bevacizumab, or ranibizumab, as monotherapy or in combination with full-fluence verteporfin photodynamic therapy. RESULTS: The two-year logMAR letters gains were significant for combination therapy ( + 10.6, P = 0.006) but not monotherapy (-2.2, P = 0.459). Over 20 years, a PCV patient would cost the health system SGD 48,790 under monotherapy and SGD 61,020 under combination therapy. Quality-adjusted life-years (QALYs) were estimated to be 7.41 for monotherapy and 7.80 for combination therapy. The incremental cost-effectiveness ratio of combination therapy was SGD 31,460/QALY, which is less than the common willingness-to-pay threshold of per capita gross domestic product of Singapore (SGD 88,990/QALY). Sensitivity analysis showed that combination therapy remained incrementally cost-effective, but not cost-saving. CONCLUSIONS: Our study shows that combination therapy is good value for money but is likely to increase costs when applied in real-world settings.

Inlays and the cornea.

Presbyopia is a growing problem in view of an aging global population and increasingly patients desire spectacle-free solutions to address this condition. Surgically implanted corneal inlays have been the topic of renewed research efforts in the past several years as a treatment option for presbyopia, with several approaches being used to modify the refractive properties of the cornea and enhance near vision. In this review we discuss historical approaches to corneal inlay surgery, critically appraise the current generation of presbyopia-correcting corneal inlays and their associated complications and consider the future prospects for emerging corneal inlay technologies that aim address the shortcomings of currently available inlays.

Gene-Based Therapeutics for Inherited Retinal Diseases.

Inherited retinal diseases (IRDs) are a heterogenous group of orphan eye diseases that typically result from monogenic mutations and are considered attractive targets for gene-based therapeutics. Following the approval of an IRD gene replacement therapy for Leber's congenital amaurosis due to RPE65 mutations, there has been an intensive international research effort to identify the optimal gene therapy approaches for a range of IRDs and many are now undergoing clinical trials. In this review we explore therapeutic challenges posed by IRDs and review current and future approaches that may be applicable to different subsets of IRD mutations. Emphasis is placed on five distinct approaches to gene-based therapy that have potential to treat the full spectrum of IRDs: 1) gene replacement using adeno-associated virus (AAV) and nonviral delivery vectors, 2) genome editing via the CRISPR/Cas9 system, 3) RNA editing by endogenous and exogenous ADAR, 4) mRNA targeting with antisense oligonucleotides for gene knockdown and splicing modification, and 5) optogenetic approaches that aim to replace the function of native retinal photoreceptors by engineering other retinal cell types to become capable of phototransduction.

Real-World Treatment Outcomes of Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy in Asians.

PURPOSE: To describe the 12-month outcomes of treatment-naïve eyes with choroidal neovascularization (CNV) resulting from age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) after initiation of intravitreal anti-vascular endothelial growth factor (VEGF) monotherapy or combination therapy with verteporfin photodynamic therapy (PDT). DESIGN: A 12-month single-center, retrospective, comparative, nonrandomized cohort study. PARTICIPANTS: Patients with AMD or PCV who initiated intravitreal anti-VEGF therapy during 2015. METHODS: Demographics, visual outcomes, OCT, and treatment data were collected at baseline and months 1, 3, 6, and 12 after treatment initiation. Multivariate analysis was performed to identify baseline features predictive of visual maintenance and improvement after 12 months of treatment. MAIN OUTCOME MEASURES: Primary end point was visual acuity (VA) change from baseline to month 12. Secondary end points were treatment exposure and change in central subfield thickness on OCT. RESULTS: A total of 364 patients (165 AMD and 199 PCV) were included. Baseline vision was 41 and 43 logarithm of the minimum angle of resolution (logMAR) letters for AMD and PCV patients, respectively. Patients with AMD and PCV received 5.5 and 5.3 injections (5.0 monotherapy vs. 5.6 combination therapy; mean, 1.2 PDT sessions), respectively. Patients with AMD gained 4.7 logMAR letters after 12 months (P = 0.002), whereas PCV patients gained 6.6 logMAR letters (P = 0.001) and 10.8 logMAR letters (P < 0.001) for monotherapy and combination therapy, respectively. Only patients with presenting VA of fewer than 35 letters (Snellen equivalent, 6/60) achieved significant visual improvement (10.4 letters for AMD, 17.1 letters for PCV with monotherapy, and 35.5 letters for PCV with combination therapy). Predictors of VA gain included number of intravitreal injections (AMD and PCV adjusted odds ratio, 12.1 [P = 0.001] and 12.5 [P = 0.004] for ≥7 injections, respectively) and baseline VA of 20 logMAR letters or fewer (adjusted odds ratio, 3.8 and 10.6 for AMD and PCV, respectively). Age, gender, race, use of PDT or focal laser therapy, and central subfield thickness were not predictive of significant visual gain at 12 months. CONCLUSIONS: In Asian patients, treatment of AMD with anti-VEGF therapy yielded 12-month visual outcomes comparable with those of other real-world studies from Western populations but poorer than those of controlled trials. In contrast, for PCV eyes, anti-VEGF monotherapy and combination therapy with PDT yielded comparable outcomes as those of controlled clinical trials.

Mediators of Corneal Haze Following Implantation of Presbyopic Corneal Inlays.

Purpose: To identify protein mediators of corneal haze following presbyopic corneal inlay surgery. Methods: Tears were collected from eyes with corneal haze following surgery with a shape-changing corneal inlay. Samples were subjected to quantitative proteomic analysis using iTRAQ and proteins significantly increased or decreased (1.3-fold or more) in haze eyes relative to fellow eyes were identified. Expression ratios were compared to postoperative eyes without corneal haze to identify proteins selectively increased or decreased in corneal haze eyes. Results: Inlay-associated haze occurred in 35% of eyes (6 of 17). Of 1443 unique tear proteins identified, eight proteins were selectively reduced in tears from postoperative haze eyes and one protein selectively increased. Proteins reduced in haze eyes included complement 4a (level relative to nonhaze eyes 0.464, P = 0.037), complement factor H (0.589, P = 0.048), immunoglobulin kappa variable 2-29 (0.128, P = 0.006), immunoglobulin kappa variable 2D-28 (0.612, P = 0.025), immunoglobulin lambda variable 7-46 (0.482, P = 0.007), S100 calcium binding protein A4 (0.614, P = 0.048), Shootin-1 (0.614, P = 0.048), and tissue inhibitor of metalloproteinase-1 (0.736, P = 0.023). The Xaa-Pro aminopeptidase 1 was increased in haze eyes relative to nonhaze eyes (1.517, P = 0.023). Conclusions: Corneal haze following corneal inlay surgery is associated with reduction in levels of known inflammatory and immune mediators. These findings represent a starting point for elucidation of pathways involved in corneal haze following synthetic inlay implantation and may enable development of targeted therapies that modulate the haze response.

White spot syndrome virus open reading frame 222 encodes a viral E3 ligase and mediates degradation of a host tumor suppressor via ubiquitination.

We have characterized a white spot syndrome virus (WSSV) RING-H2-type protein, WSSV222, which is involved in ubiquitination. WSSV222 exhibits RING-H2-dependent E3 ligase activity in vitro in the presence of the specific conjugating enzyme UbcH6. Mutations in the RING-H2 domain abolished WSSV222-dependent ubiquitination, revealing the importance of this domain in WSSV222 function. Yeast two-hybrid and pull-down analyses revealed that WSSV222 interacts with a shrimp tumor suppressor-like protein (TSL) sharing 60% identity with human OVCA1. To better characterize the interaction of WSSV222 and TSL in vivo, we established a stable TSL-expressing cell line derived from the human ovarian cancer cell line A2780, where we observed a TSL-dependent prolonged G1 phase. Furthermore, we detected WSSV222-mediated ubiquitination and MG132-sensitive degradation of TSL both in shrimp primary cell culture and in the TSL-expressing cell line. Transient expression of TSL in BHK cells leads to apoptosis, which was rescued by WSSV222. Taken together, our data suggest that WSSV222 acts as an antiapoptosis protein by ubiquitin-mediated proteolysis of TSL to ensure successful WSSV replication in shrimp.