Method for Angiographically Guided Fine-Needle Diathermy in the Treatment of Corneal Neovascularization

Corneal Opacity in the United States: An American Academy of Ophthalmology IRIS® Registry (Intelligent Research in Sight) Study

PURPOSE

Vision loss associated with opacification of the cornea is one of the leading causes of blindness globally. However, the epidemiological data pertaining to the demographics, associated etiological causes and reduced vision in corneal opacity patients continue to be sparse. This study assesses the case frequencies, underlying etiologies, and vision outcomes in patients diagnosed with corneal opacity, in the United States.

DESIGN

Retrospective cohort study PARTICIPANTS: Patients in the IRIS® Registry (Intelligent Research in Sight) who were diagnosed with corneal opacity between January 1st, 2013, and November 30th, 2020.

METHODS

The IRIS Registry contains demographic and clinical data of 79,887,324 patients who presented to eye clinics during the study period. We identified patients with corneal opacity using International Classification of Disease (ICD) codes (ICD-9, and -10) of "371" (corneal scar) and "H17" (corneal opacity), respectively. The analyzed data included demographic parameters included age, sex, race, ethnicity, and geographical location. We evaluated clinical data including laterality, etiology, disease descriptors, and best-corrected visual acuity (VA) up to 1 year before the onset (± 30 days), at the time of diagnosis, and at one year following diagnosis (± 30 days).

MAIN OUTCOME MEASURES

Case frequencies, etiology, and vision outcomes in patients diagnosed with corneal opacity.

RESULTS

We identified 5,220,382 patients who were diagnosed with corneal opacity and scars using H17 (ICD-10) and 371.0 (ICD-9) codes over seven years. The case frequency of corneal opacity during the study period was 6,535 cases per 100,000 patients (6.5%). The mean age of the patients was 63.36±18.14 years and the majority were female (57.6%). In the cohort, 38.39% and 30.00% of patients had bilateral and unilateral corneal opacity, respectively. Most of the patients were White (69.13%), followed by Black or African American (6.84%), Asian (2.45%), American Indian or Alaska Native(0.34%), Native Hawaii or other Pacific Islander(0.19%). Among the patients with corneal opacity, 7.34% had Hispanic or Latino ethnicity. The primary etiologies associated with corneal opacity included corneal dystrophies (64.66%) followed by edema (18.25%), ulcer (7.78%), keratoconjunctivitis (7.18%), degeneration (5.62%), neovascularization (6.27%), and trauma (5.28%). Visual acuity of the patients significantly worsened due to corneal opacity (0.46±0.74 logMAR; ∼20/58 in Snellen) and did not improve to the baseline (0.37±0.68 logMAR, ∼20/46 in Snellen) post-management (0.43±0.77 logMAR, ∼20/54 in Snellen). The multiple linear regression analysis showed worse vision outcomes in females (compared to males), and Asian, Black or African American, and American Indian or Alaska Native (compared to White) patients. Additionally, worse vision outcomes were observed in patients with opacity associated with corneal malformation, degenerative disorders, edema, injury, and ulcer compared to those with hereditary corneal dystrophy.

CONCLUSIONS

Our study shows that the corneal opacity was diagnosed in 6.5% of the patients in the IRIS Registry and it was primarily associated with corneal dystrophies. The final vision outcomes in corneal opacity patients were significantly worse compared to baseline. The worse vision outcomes were associated with sociodemographic differences that might be associated with disparities in access, utilization, and care patterns.

Recent advances in corneal neovascularization imaging

Corneal neovascularization (CoNV) is a vision-threatening ocular disease commonly secondary to infectious, inflammatory, and traumatic etiologies. Slit lamp photography, in vivo confocal microscopy, angiography, and optical coherence tomography angiography (OCTA) are the primary diagnostic tools utilized in clinical practice to evaluate the vasculature of the ocular surface. However, there is currently a dearth of comprehensive literature that reviews the advancements in imaging technology for CoNV administration. Initially designed for retinal vascular imaging, OCTA has now been expanded to the anterior segment and has shown promising potential for imaging the conjunctiva, cornea, and iris. This expansion allows for the quantitative monitoring of the structural and functional changes associated with CoNV. In this review, we emphasize the impact of algorithm optimization in anterior segment-optical coherence tomography angiography (AS-OCTA) on the diagnostic efficacy of CoNV. Through the analysis of existing literature, animal model assessments are further reported to investigate its pathological mechanism and exhibit remarkable therapeutic interventions. In conclusion, AS-OCTA holds broad prospects and extensive potential for clinical diagnostics and research applications in CoNV.

Current trends in the management of corneal neovascularization

PURPOSE OF REVIEW

The aim of this study was to highlight recent developments in the medical and surgical management of corneal neovascularization (NV).

RECENT FINDINGS

Improved understanding and diagnostic criteria among clinicians have led to advancements in the characterization of corneal NV and objective assessment of treatment response through ancillary imaging devices. Developments in corneal NV treatments, such as antivascular endothelial growth factor, fine needle diathermy, and photodynamic therapy, have improved treatment success rates and visual outcomes. More recent surgical treatment advancements include corneal cross-linking, endothelial keratoplasty, and mitomycin intravascular chemoembolization. Finally, a greater appreciation of the molecular pathogenesis and angiogenic factors involved in corneal NV has identified numerous potential targeted therapies in the future.

SUMMARY

The management of corneal NV has evolved to include several standalone and combination medical and surgical options. Additionally, improvements in quantifying corneal NV and understanding its molecular basis have contributed to new management strategies with improved outcomes.

Management of corneal neovascularization: Current and emerging therapeutic approaches

Corneal neovascularization (CoNV) is a sight-threatening condition affecting an estimated 1.4 million people per year, and the incidence is expected to rise. It is a complication of corneal pathological diseases such as infective keratitis, chemical burn, corneal limbal stem cell deficiency, mechanical trauma, and immunological rejection after keratoplasties. CoNV occurs due to a disequilibrium in proangiogenic and antiangiogenic mediators, involving a complex system of molecular interactions. Treatment of CoNV is challenging, and no therapy thus far has been curative. Anti-inflammatory agents such as corticosteroids are the mainstay of treatment due to their accessibility and well-studied safety profile. However, they have limited effectiveness and are unable to regress more mature neovascularization. With the advent of advanced imaging modalities and an expanding understanding of its pathogenesis, contemporary treatments targeting a wide array of molecular mechanisms and surgical options are gaining traction. This review aims to summarize evidence regarding conventional and emerging therapeutic options for CoNV.

Assessment of Corneal Angiography Filling Patterns in Corneal Neovascularization

The purpose of the paper is to describe vascular filling patterns in corneal neovascularization (CoNV) and evaluate the effect of corneal lesion location, CoNV surface area and multi-quadrant CoNV involvement on the filling pattern. It is a retrospective study of patients who were investigated for CoNV using fluorescein angiography (FA) or indocyanine green angiography (ICGA) between January 2010 and July 2020. Angiography images were graded and analyzed multiple independent corneal specialists. The corneal surface was divided into four quadrants and patient information was obtained through electronic records. A total of 133 eyes were analyzed. Corneal lesions were located on the peripheral (72%) or central (28%) cornea. Central lesions were associated with multi-quadrant CoNV more frequently than peripheral lesions (p = 0.15). CoNV located within the same quadrant of the corneal lesion was often first to fill (88.4%). In multi-quadrant CoNV, the physiological inferior-superior-nasal-temporal order of filling was usually respected (61.7%). Central lesions resulted in larger CoNV surface area than peripheral lesions (p = 0.09). In multi-quadrant CoNV, the largest area of neovascularization was also the first to fill in (peripheral lesion 74%, central lesion 65%). Fillings patterns in healthy corneas have previously been reported. Despite CoNV development, these patterns are usually respected. Several factors that may influence filling patterns have been identified, including corneal lesion location, CoNV surface area and aetiology of CoNV. Understanding filling patterns of neovascularization allows for the identification of areas at higher risk of developing CoNV, aiding in earlier detection and intervention of CoNV.

Editorial: Imaging in Ophthalmology

Over the last decade, ophthalmology has significantly benefited from advances in vivo non-invasive ophthalmic imaging techniques that play currently a fundamental role in the clinical assessment, diagnosis, management, and monitoring of a wide variety of conditions involving both the anterior and posterior segment [...]

Retinal and Corneal Changes Associated with Intraocular Silicone Oil Tamponade

Silicone oils (SO) are used as long-term intraocular tamponades and have an irreplaceable role in vitreoretinal surgery. They can, however, be associated with multiple and potentially severe complications, involving different ocular tissues, in particular retina and cornea. Recent advances in ophthalmic imaging have allowed the precise characterization of retinal and corneal microstructural changes, at a subclinical level. This detailed analysis of SO-related retinal and corneal changes has improved our understanding of their pathogenesis and offer the potential for optimized monitoring and management of patients with SO-filled eyes. This review aims to provide clinicians and ophthalmic scientists with an updated and comprehensive overview of the corneal and retinal changes associated with SO tamponade.

Ocular surface angiography: from neovessels to neoplasia

The ocular surface vascular system plays a key role in corneal and conjunctival inflammatory, infectious and neoplastic pathology. Angiographic vessel analysis using intravenous dyes and optical coherence tomography technology allow both the quantitative and functional assessment of conjunctival vasculature and corneal neovessels. Based on a thorough understanding of vascular alterations in ocular surface disease, angiographic assessment facilitates the clinical management of corneal neovascularisation, the grading of ocular surface inflammation and the identification of tumour angiogenesis in dysplastic or malignant lesions. This review summarises key aspects of the clinical application of corneal and conjunctival angiography as presented at the 2021 virtual Bowman Club meeting.

Imaging of vascular abnormalities in ocular surface disease

The vascular system of the ocular surface plays a central role in infectious, autoimmune, inflammatory, traumatic and neoplastic diseases. The development, application, and monitoring of treatments for vascular abnormalities depends on the in vivo analysis of the ocular surface vasculature. Until recently, ocular surface vascular imaging was confined to biomicroscopic and color photographic assessment, both limited by poor reproducibility and the inability to image lymphatic vasculature in vivo. The evolvement and clinical implementation of innovative imaging modalities including confocal microscopy, intravenous, and optical coherence tomography-based angiography now allows standardized quantitative and functional vascular assessment with potential applicability to automated analysis algorithms and diagnostics.

[Preconditioning of vascularized high-risk eyes using fine-needle diathermy and cross-linking]

BACKGROUND

The risk of allograft rejection following high-risk keratoplasty increases with the area of corneal neovascularization. Pharmaceutical and physical regression of corneal neovascularization before keratoplasty may offer the potential to reduce the risk of graft rejection after high-risk keratoplasty.

OBJECTIVE

This article provides a review of the literature on the preconditioning of vascularized high-risk eyes using fine-needle diathermy and corneal cross-linking (preoperative preconditioning by lymphangioregression).

METHODS

A literature search was carried out in PubMed and a summary of own data is presented.

RESULTS

Animal experimental studies showed that both fine-needle diathermy and corneal cross-linking lead to a regression of corneal neovascularization and prolong graft survival after high-risk keratoplasty. Furthermore, studies from our institute provide first evidence that both procedures also lead to a reduction of corneal neovascularization in the clinical practice and thus potentially reduce the risk of allograft rejection after subsequent high-risk keratoplasty.

DISCUSSION

Fine-needle diathermy and corneal cross-linking provide effective therapeutic approaches for angioregressive treatment and seem to prolong graft survival following high-risk keratoplasty. Larger prospective and controlled clinical trials are needed to further investigate these promising therapeutic approaches.

Subconjunctival Aflibercept for the Treatment of Formed Corneal Neovascularization

PURPOSE

To evaluate the effect of a single subconjunctival aflibercept injection on formed corneal neovascularization.

METHODS

A prospective clinical trial, conducted at a single tertiary medical center. Included were consecutive patients with corneal pathologies complicated by corneal neovascularization, who were candidates for anti-vascular endothelial growth factor treatment at the discretion of a cornea specialist. A single subconjunctival injection of 0.08 mL of Aflibercept (Eylea 25 mg/mL) was administered near the limbus in proximity to the areas of maximal pathological neovascularization. Follow-up visits were scheduled on days 7, 30, 60, and 90 following injection. Best-corrected visual acuity (BCVA), intraocular pressure, slitlamp examination, digital cornea photography, specular microscopy, and anterior-segment optical coherence tomography were documented at each visit. The images were graded by a masked observer for density, extent, and centricity of corneal vascularization.

RESULTS

Six eyes of six patients were analyzed. No clinically significant ocular or systemic adverse events were documented. No change was noted in extent, density, or centricity of corneal blood vessels at seven, 30, and 90 days after injection (P>0.1 for all time point comparisons, Friedman test). Best-corrected visual acuity fluctuated insignificantly in 5/6 patients during follow-up time, and objective but not subjective improvement of BCVA was noted in one patient with no concurrent change of neovascularization. The recruitment has therefore halted prematurely.

CONCLUSIONS

A single subconjunctival aflibercept injection seems to be well tolerated. However, it is ineffective for regressing formed corneal neovascularization.

Visualization of corneal vascularization in peripheral hypertrophic subepithelial corneal opacification with OCT angiography

PURPOSE

The major goal of this study was to test the hypothesis that in patients with peripheral hypertrophic subepithelial corneal opacification (PHSCO), visualization of corneal vessels is better with optical coherence tomography angiography (OCTA) than with conventional slit lamp microphotography.

METHODS

Patients with PHSCO were included in this prospective study. The corneal findings were photographed using a slit lamp camera (Haag Streit BM 900^® ) and visualized with anterior-segment OCT (Optovue XR Avanti, Fremont, California, USA). Additionally, OCTA with the Angiovue Imaging™ System was performed in the area of PHSCO.

RESULTS

Thirty-four eyes of 19 patients (26% male and 74% female) with PHSCO were included in this study. In 21 eyes, vascularization in the area of PHSCO was visualized with the Angiovue-OCT, whereas only 10 eyes presented vessels in slit lamp photographs.

CONCLUSION

Optical coherence tomography angiography allows better visualization of corneal neovascularization than slit lamp photography in patients with PHSCO. Corneal opacifications were found predominantly nasally, which was reflected by a local enlargement of corneal thickness.

Functional Staging of Corneal Neovascularization Using Fluorescein and Indocyanine Green Angiography

Purpose

Corneal neovascularization (CoNV) is a major risk factor for corneal graft rejection and other corneal conditions. The maturity of CoNV is important to guide treatment. This study investigated associations between clinical and angiographic characteristics of CoNV.

Methods

In a prospective cross-sectional study patients with CoNV of variable but known duration and etiology were included. All cases were clinically staged according to a simplified three-grade scale as active, inactive, and regressed and assessed using color photography, anterior-segment optical coherence tomography, and fluorescein and indocyanine green (ICG) angiography. Outcome parameters included age and depth of CoNV, perfusion times and time to leakage of fluorescein and ICG.

Results

Forty eyes of 39 patients with CoNV were included, active (14), inactive (22), and regressed CoNV (4). There were significant associations between the time to fluorescein or ICG leakage and clinical staging of CoNV (R² = 0.24; P = 0.0011, and R² = 0.3; P = 0.0001). In addition, there was a significant association between the time to fluorescein leakage and the age of CoNV (R² = 0.32; P = 0.0002). ICG leakage within 10 minutes was observed significantly more frequently in active than the inactive group and was not observed in regressed cases (P < 0.0001).

Conclusions

Simplification of the staging of CoNV to active, inactive, and regressed to is significantly associated with the time to extravascular leakage of fluorescein and indocyanine and may be useful to guide the selection of appropriate treatments.

Translational Relevance

The association between clinical and angiographic characteristics of CoNV may provide guidance to the treatment approaches.

Therapeutic approaches for corneal neovascularization

Angiogenesis refers to new blood vessels that originate from pre-existing vascular structures. Corneal neovascularization which can lead to compromised visual acuity occurs in a wide variety of corneal pathologies. A large subset of measures has been advocated to prevent and/or treat corneal neovascularization with varying degrees of success. These approaches include topical corticosteroid administration, laser treatment, cautery, and fine needle diathermy. Since the imbalance between proangiogenic agents and antiangiogenic agents primarily mediate the process of corneal neovascularization, recent therapies are intended to disrupt the different steps in the synthesis and actions of proangiogenic factors. These approaches, however, are only partially effective and may lead to several side effects. The aim of this article is to review the most relevant treatments for corneal neovascularization available so far.