Ultra high-resolution anterior segment optical coherence tomography in the diagnosis and management of ocular surface squamous neoplasia

It Is All About the Angle: A Clinical and Optical Coherence Tomography Comparison of Corneal Ocular Surface Squamous Neoplasia and Corneal Pannus

PURPOSE

The aim of this study was to compare clinical characteristics and high-resolution optical coherence tomography (HR-OCT) findings between corneal ocular surface squamous neoplasia (OSSN) and corneal pannus.

METHODS

Retrospective study of 9 individuals, 3 with lesions histologically confirmed to be OSSN, 3 with lesions histologically confirmed to be pannus, 1 with lesions histologically confirmed to be OSSN followed by pannus, and 2 with long-standing, nonchanging lesions clinically diagnosed as pannus. All individuals presented to the Miami Veterans Affairs Medical Center eye clinic or Bascom Palmer Eye Institute between 2015 and 2023. Clinical characteristics and HR-OCT findings were evaluated and compared.

RESULTS

Mean age of the population was 72.8 ± 5.1 years, 100% self-identified as male, 100% as White, and 11.1% as Hispanic. Clinically, all lesions appeared as whitish, opalescent, variably vascularized opacities extending from the limbus. None of the OSSN cases had vessels that extended to the border, whereas 4 cases of pannus (67%) had at least 1 vessel that reached the border. On HR-OCT, epithelial hyperreflectivity was observed in all cases of OSSN and pannus. Epithelial thickening was observed in all cases of OSSN, but in none of the cases of pannus. An important distinction between the 2 groups was the transition between normal and abnormal epithelium. All cases of OSSN had a vertical transition, whereas all cases of pannus had an angled transition.

CONCLUSIONS

Corneal OSSN and corneal pannus can both present with clinical findings of an opalescent lesion and may have overlapping findings on HR-OCT. Although both entities may show epithelial hyperreflectivity on HR-OCT, OSSN demonstrates an abrupt transition at a vertical, 90 degrees angle perpendicular to the Bowman layer, whereas pannus appears as an angled transition around 45 degrees. Therefore, the angle of transition between normal and abnormal epithelium can be useful in distinguishing between the 2 entities.

Conjunctival keratoacanthoma: a clinical and histopathological case series

OBJECTIVE

To present a series of conjunctival keratoacanthomas and provide clinical, histopathological, immunohistochemical, and imaging results that characterize this rare entity.

METHODS

A retrospective chart review of records from 2005 to 2023 from the Florida Lions Ocular Pathology Laboratory was conducted. Nine patients with histologically proven conjunctival keratoacanthoma were identified. Data extracted includes demographics, clinical history, diagnostic testing, histopathological and immunohistochemical testing, treatment modalities, and recurrences.

RESULTS

Patients' mean age was 55.2 ± 21.1 years (range: 22-83). 77.8% (7/9) of patients were male. 55.6% (5/9) were Hispanic. 55.6% of lesions (5/9) were in right eyes. 55.6% of lesions (5/9) were on the temporal, bulbar conjunctiva. The lesions were rapidly growing, with mean onset time of 4.71 ± 3.30 weeks (range: 2-12). High-resolution anterior segment optical coherence tomography of three lesions revealed hyper-reflective, thickened epithelium with abrupt transition between normal and abnormal epithelium. Underlying disorganized subepithelial tissue was noted. However, the overlying abnormal epithelium caused considerable shadowing, which obscured subepithelial structures. Prominent, keratin-filled, cup-shaped lesions with faulty maturational sequencing that extend full thickness, variably pale cytoplasm, and foci of dyskeratosis and hyperkeratosis were present on all lesions' histopathology. All lesions were surgically excised, but two demonstrated partial spontaneous resolution before surgery. Two patients were lost to follow-up; the remaining seven had no signs of recurrence at a of mean of 36.9 ± 45.4 months (range: 3 to 141 months) of follow-up.

CONCLUSIONS

Conjunctival keratoacanthomas are rare lesions of the ocular surface with distinct clinical, histopathologic, and diagnostic features.

Can high-resolution optical coherence tomography provide an optical biopsy for ocular surface lesions?

High-resolution optical coherence tomography (HR-OCT) has transformed the diagnosis and management of ocular surface lesions. Providing a detailed cross-sectional view of the cornea and conjunctiva, HR-OCT can be used to identify characteristic features of various benign and malignant ocular surface lesions, aiding in their diagnosis and guiding treatment. When incorporated into an ophthalmology clinic, HR-OCT provides morphological images of lesions in a noninvasive means, akin to an "optical biopsy". The characteristic HR-OCT features of several lesions have been well described in the literature, including for ocular surface squamous neoplasia, papilloma, melanoma, primary acquired melanosis, complexion associated melanosis, nevus, pterygium, pinguecula, lymphoma, and amyloidosis. HR-OCT can be used to differentiate between lesions with similar clinical features, lesions that co-exist on the same ocular surface, and atypically presenting lesions, such as pigmented ocular surface squamous neoplasia or amelanotic melanoma. The management of ocular surface lesions has been transformed by the implementation of HR-OCT, providing clinicians with the ability to monitor tumor response to topical chemotherapies, follow previously excised lesions for recurrence, and map out tumor borders intraoperatively. While there are some limitations to HR-OCT, including imaging of thick or deep lesions, it has become an essential tool for ocular oncologists in the management of ocular surface lesions.

Tear meniscus particle analysis with anterior segment optical coherence tomography in keratoconus

PURPOSE

To perform tear meniscus particle analysis using anterior segment spectral domain-optical coherence tomography (SD-OCT) and ImageJ software in keratoconus patients.

METHODS

A total of 76 participants (76 eyes) were included in the study. A comprehensive analysis of tear meniscus parameters, including tear meniscus height (TMH), tear meniscus depth (TMD), tear meniscus turbidity (TMT), and percentage of area occupied by particles (PAOP) within the meniscus, was performed in kerataconus patients and healthy controls.

RESULTS

TMT was significantly higher in the keratoconus group, while PAOP was significantly lower (P < 0.05). However, TMH and TMD did not show significant differences between the two groups (P > 0.05). There was a negative correlation observed between TMT and PAOP. In binary logistic regression analysis, TMT and Schirmer score were found to be the most influential factors in predicting keratoconus (odds ratio [OR] = 0.995, P = 0.039 and OR = 1.143, P = 0.021, respectively).

CONCLUSION

This study revealed novel findings on analysis of the tear film in keratoconus patients, with higher TMT and lower POAP levels in the keratoconus group compared to the healthy control group.

Corneal Microaneurysm-A Vascular Feature of Conjunctival Squamous Intraepithelial Neoplasia

PURPOSE

The diagnosis of conjunctival squamous intraepithelial neoplasia (CSIN) can be difficult because of the heterogeneous appearance. Despite established risk factors and diagnostic support by high-resolution optical coherence tomography (hrOCT) and indocyanine green angiography (ICGA), the only reliable diagnostic method is a histological work-up. This case report is the first to describe corneal microaneurysms in CSIN as a vascular feature for conjunctival tumor angiogenesis.

METHODS

An 84-year-old male patient was referred with a suspected diagnosis of pterygium. Biomicroscopic examination revealed a whitish epithelial lesion of conjunctival origin with centripetal corneal growth and extension over 5 limbal hours. Intralesional vascularization showed highly altered morphology with aneurysmal changes. After imaging with hrOCT and ICGA, excision was performed in a "no-touch double-freeze and thaw" technique, followed by histological and immunohistochemical work-up.

RESULTS

hrOCT showed an epithelial, hyperreflective lesion with a maximum thickness of 272 µm and sharp central border. ICGA confirmed active perfusion and partial thrombosis of the aneurysmal terminal vascular buds dilated to 405 μm with early dye leakage within the first minute. Histological examination confirmed the clinical diagnosis of CSIN with focal high-grade dysplasia. Postoperatively, there was no recurrence during the observation period of 5 months.

CONCLUSIONS

Intralesional terminal microaneurysms are a feature of tumor angiogenesis in CSIN. The relevance and frequency of this potential new risk factor for malignancy should be investigated in further studies.

Chronic inflammation as a proposed risk factor for ocular surface squamous neoplasia

PURPOSE

Chronic inflammation is a predisposing factor for metaplastic changes and ultimately dysplasia. We describe cases of OSSN occurring in the setting of chronic ocular surface inflammation.

METHODS

Sixteen eyes from 14 individuals were included from one ocular oncology clinic between 2010 and 2023. Patients presented with ocular surface squamous neoplasia (OSSN) in the setting of chronic inflammation. The diagnosis of OSSN was made using anterior segment high-resolution optical coherence tomography (HR-OCT) and confirmed by histopathological analysis in all cases.

RESULTS

Median age on presentation was 61 [IQR 47.5-69.2] years. Eleven (86%) individuals were male and five (36%) identified as White Hispanic. Ten eyes were referred with ocular surface diagnoses including pannus (n = 4), scarring (n = 3), pterygium (n = 2), and herpetic keratitis (n = 1). Only six eyes were referred as possible neoplasia. All individuals had a history of ocular surface inflammation. The most common inflammatory conditions were ocular rosacea (seven individuals) and atopic keratoconjunctivitis (AKC) (five individuals). Two individuals were found to have bilateral OSSN, one in the setting of ocular rosacea and the other in the setting of AKC. All 16 eyes from 14 individuals were suspected to have OSSN based on HR-OCT findings which guided the location of the incisional biopsies that subsequently confirmed histopathological diagnosis in all cases.

CONCLUSION

OSSN may arise in the setting of chronic inflammation on the ocular surface. Identification of the tumor can be challenging in these cases, and HR-OCT can be a key diagnostic tool in detecting OSSN.

Novel automated non-invasive detection of ocular surface squamous neoplasia using artificial intelligence

Ocular surface squamous neoplasia (OSSN) is a common eye surface tumour, characterized by the growth of abnormal cells on the ocular surface. OSSN includes invasive squamous cell carcinoma (SCC), in which tumour cells penetrate the basement membrane and infiltrate the stroma, as well as non-invasive conjunctival intraepithelial neoplasia, dysplasia, and SCC in-situ thereby presenting a challenge in early detection and diagnosis. Early identification and precise demarcation of the OSSN border leads to straightforward and curative treatments, such as topical medicines, whereas advanced invasive lesions may need orbital exenteration, which carries a risk of death. Artificial intelligence (AI) has emerged as a promising tool in the field of eye care and holds potential for its application in OSSN management. AI algorithms trained on large datasets can analyze ocular surface images to identify suspicious lesions associated with OSSN, aiding ophthalmologists in early detection and diagnosis. AI can also track and monitor lesion progression over time, providing objective measurements to guide treatment decisions. Furthermore, AI can assist in treatment planning by offering personalized recommendations based on patient data and predicting the treatment response. This manuscript highlights the role of AI in OSSN, specifically focusing on its contributions in early detection and diagnosis, assessment of lesion progression, treatment planning, telemedicine and remote monitoring, and research and data analysis.

Toluidine blue 1% eye drop versus optical coherence tomography for margin delimitation of ocular surface squamous neoplasia

PURPOSE

To compare the use of toluidine blue 1% eye drops with anterior segment optical coherence tomography (OCT) for the determination of tumour margins in patients with ocular surface squamous neoplasia (OSSN).

METHODS

The study was conducted from July 2020 to June 2021 at the Ocular Oncology department at the Federal University of São Paulo, Brazil. Slit-lamp photographs after toluidine blue staining and OCT of the anterior segment were taken on the same day from patients with OSSN. Photographs and OCT images were analyzed quantitatively using the software ImageJ and IMAGEnet®, respectively. The agreement between techniques was evaluated qualitatively through the Bland-Altman graph and quantitatively through intraclass correlation (ICC).

RESULTS

A total of 21 participants (71.43% males) with a clinical diagnosis of OSSN were included in the study. The average + SD diameter along the chosen axes was 4.43 ± 2.08 mm with OCT of 4.37 ± 2.03 mm with toluidine blue, a difference not statistically significant (p = 0.2891). The Bland-Altman analysis indicated a good qualitative agreement between the methods, with all cases inserted within the limits of agreement from -0.3217 to 0.4268. The ICC quantitative analysis showed an almost perfect agreement of 99.57% (95%CI: 98.96-99.83%; p < 0.001).

CONCLUSIONS

Our findings showed that OCT and toluidine eye drops are equivalent in determining margins for tumour measurements, which is particularly relevant in low-income settings where anterior segment OCT is not available. The use of toluidine blue 1% could be an useful alternative to quantify the size of the tumour, help to monitor tumour growth, and outline margins for surgical planning.

Intraocular Invasion by Conjunctival Squamous Cell Carcinoma: Clinical Presentation, Histopathological Findings, and Outcome

Introduction

Intraocular localization of conjunctival squamous cell carcinoma (SCC) is due to scleral or corneal invasion. Herein, we describe the clinical and histopathological findings in four cases of SCC complicated by intraocular invasion, and we review cases reported in the literature and their management. We retrospectively collected and analyzed clinical characteristics, histopathology, management, and follow-up data from 4 patients with conjunctival SCC complicated by intraocular invasion. We reviewed the literature and summarized cases of intraocular invasion by conjunctival SCC reported over the last 30 years.

Case Presentations

Two patients presented with intraocular invasion by conjunctival SCC at diagnosis. The two others developed intraocular invasion as recurrence of conjunctival SCC, previously treated with excisional biopsy and adjuvant radiotherapy. All 4 cases had a previous history of conjunctival surgery, but no history of intraocular surgery. Three patients were managed with modified enucleation, including one that required adjuvant orbital radiotherapy. One patient required orbital exenteration. Histopathology analysis showed a well-differentiated conjunctival SCC in all cases. None developed distant localization after at least 2.5-year follow-up.

Discussion/Conclusion

Intraocular invasion is a rare complication of conjunctival SCC. Appropriate treatment in a tertiary center and long-term follow-up are highly recommended.

Corneal layer thickness in keratoconus using optical coherence tomography

CLINICAL RELEVANCE

Accurate thickness measurement of corneal layers using anterior segment OCT can be used to improve visual outcomes. Understanding its applications is essential for optometric practices to enhance eye care procedures.

BACKGROUND

To evaluate the thicknesses of different corneal layers for identifying keratoconus (KCN) and subclinical keratoconus (SKCN) using spectral-domain optical coherence tomography (SD-OCT).

METHODS

This prospective study analyzed 60 eyes with KCN, 48 eyes with SKCN, and 53 normal eyes. The central corneal thickness (CCT) and thicknesses of the epithelium, Bowman, stroma, and Descemet-endothelium layers were measured using SD-OCT. One way analysis of variance and the area under the curve (AUC) were used to evaluate the parameters. The Delong method was used to compare AUCs.

RESULTS

In KCN, CCT and thicknesses of epithelium, Bowman, stroma, and Descemet-endothelium layers were 495.5 ± 41.7, 52.6 ± 6.4,11.5 ± 1.4, 415.5 ± 38.9, and 12.3 ± 1.7 µm, respectively. These thickness values were respectively 524.5 ± 33.3, 56.8 ± 6.8, 11.5 ± 1.6, 439.8 ± 30.6, and 12.4 ± 1.7 µm in SKCN and 563.8 ± 37.9, 57.7 ± 6.9, 12.2 ± 1.6, 469.5 ± 33.7, and 12.8 ± 2.1µm in normal group. Total cornea and stroma in KCN and SKCN, and epithelium in KCN were significantly thinner compared to the normal group (P < 0.001). The highest AUC values were observed for CCT in KCN (AUC 0.90) and SKCN (AUC 0.782). The diagnostic accuracy was significantly higher for stromal thickness in KCN (sensitivity 81.7%, specificity 73.6%, AUC 0.871) and SKCN (sensitivity 80.0%, specificity 56.6%, AUC 0.751) than other individual corneal layers (Delong, P < 0.001)                                    .

CONCLUSION

CCT can accurately distinguish keratoconus from normal eyes. However, central corneal stromal thinning was the most sensitive diagnostic index for early detection of SKCN. Developing standardized stromal maps may be helpful for detecting SKCN.

Molecular and epigenetic mechanisms governing ocular surface squamous neoplasia: opportunities for diagnostics

INTRODUCTION

Ocular surface squamous neoplasia (OSSN) is the most common ocular malignancy; the pathophysiology is influenced by molecular, genetic, and epigenetic mechanisms. The incidence of OSSN is associated with the anatomy and physiology of the ocular surface, limbal stem cell configuration, limbal vulnerability, cancer stem cells, dysplasia, neoplasia, angiogenesis, invasion, and metastasis. The key etiological factors involved are human papillomavirus (HPV), human immunodeficiency virus (HIV), immunosuppression, p53 tumor suppressor gene, hypovitaminosis A, and failure of Deoxyribonucleic acid (DNA) repair mechanisms.

AREAS COVERED

This special report is a focussed attempt to understand the molecular mechanism, genetic and epigenetic mechanism, and diagnostic modalities for OSSN.

EXPERT OPINION

While these mechanisms contribute to genome instability, promoter-specific hypermethylation might facilitate and promote tumor formation by silencing tumor suppressor genes. OSSN understanding has improved with increased literature available on various genetic, molecular, and epigenetic mechanisms, although the exact genetic and epigenetic mechanisms still need to be elucidated. It is important to note that the molecular mechanisms of OSSN can vary among individuals, and further research is required to elucidate the underlying processes fully. Understanding these mechanisms is crucial for the development of targeted therapies and improved management of OSSN.

Three-dimensional in vivo evaluation of the cornea in patients with unilateral posterior interstitial keratitis

Purpose

The purpose of this study was to investigate the in vivo morphologic features of the cornea in patients with unilateral posterior interstitial keratitis.

Methods

Seven eyes of 7 patients with unilateral posterior interstitial keratitis were examined by slit-lamp biomicroscopy, anterior segment optical coherence tomography (AS-OCT), and in vivo confocal microscopy (IVCM). The imaging features of the cornea were evaluated and analyzed.

Results

By slit-lamp examination, the posterior corneal stromal opacities were observed in all 7 eyes, and deep neovascularization in 4 eyes. The posterior stromal opacities showed higher reflectivity with an intact overlying epithelium by AS-OCT and did not invade the Bowman's layer in all cases. IVCM revealed highly reflective dispersed microdots, needle-shaped bodies, and increased reflectivity of keratocytes in the lesion site in all patients. Active Langerhans cells and an attenuated subbasal nerve plexus were observed in 5 eyes. After treatment, the active Langerhans cells disappeared; however, highly reflective microdots and needle-shaped bodies remained.

Conclusion

The three-dimensional evaluation of slit-lamp biomicroscopy, AS-OCT, and IVCM may help in the early diagnosis of patients with posterior interstitial keratitis.

Diagnosis of Acanthamoeba Keratitis: Past, Present and Future

Acanthamoeba keratitis (AK) is a painful and sight-threatening parasitic corneal infection. In recent years, the incidence of AK has increased. Timely and accurate diagnosis is crucial during the management of AK, as delayed diagnosis often results in poor clinical outcomes. Currently, AK diagnosis is primarily achieved through a combination of clinical suspicion, microbiological investigations and corneal imaging. Historically, corneal scraping for microbiological culture has been considered to be the gold standard. Despite its technical ease, accessibility and cost-effectiveness, the long diagnostic turnaround time and variably low sensitivity of microbiological culture limit its use as a sole diagnostic test for AK in clinical practice. In this review, we aim to provide a comprehensive overview of the diagnostic modalities that are currently used to diagnose AK, including microscopy with staining, culture, corneal biopsy, in vivo confocal microscopy, polymerase chain reaction and anterior segment optical coherence tomography. We also highlight emerging techniques, such as next-generation sequencing and artificial intelligence-assisted models, which have the potential to transform the diagnostic landscape of AK.

Clinic-pathological agreement in the diagnosis of conjunctival tumours: Analysis of 195 cases

PURPOSE

The present study aims to assess the agreement between clinical and pathological diagnosis in conjunctival tumours in a specialist ocular oncology unit.

METHODS

retrospective study of consecutive patients with conjunctival tumours diagnosed at the Ocular Oncology Unit of the University Hospital of Valladolid was performed from 1992 to 2017. Tumours were classified according to their origin (epithelial, melanocytic, lymphoid and others) and degree of malignancy (benign, premalignant, malignant). A biopsy was performed in cases of symptomatic or growing lesions. Cohen´s kappa (κ) statistics was used as an indicator of agreement between clinical and pathological diagnosis.

RESULTS

Of 462 consecutive patients, a biopsy was required in 195 (42.2%). The agreement with the pathological diagnosis was successful in 154 (79.0%) cases. Analysis according to the grade of malignancy showed the lowest rate of agreement among benign (n = 83; 91.6%) and premalignant (n = 62; 90.3%) lesions, with a total agreement in malignant lesions (n = 50; 100%); the Cohen´s kappa coefficient (κ) was 0.90. The highest rates of concordance were found in epithelial, melanocytic and soft tissue lesions with κ values of 1, 0.8 and 1 respectively. The worst rate of concordance was found in lymphoid lesions with a κ value of 0.3.

CONCLUSION

Most of the conjunctival tumours were correctly identified clinically; benign and malignant lesions showed the highest rate of accuracy; however, premalignant tumours can hide micro-invasive diseases that can go unnoticed on clinical examination. The biopsy is essential for accurate diagnosis and treatment.

Time-domain full-field optical coherence tomography (TD-FF-OCT) in ophthalmic imaging

Ocular imaging plays an irreplaceable role in the evaluation of eye diseases. Developing cellular-resolution ophthalmic imaging technique for more accurate and effective diagnosis and pathogenesis analysis of ocular diseases is a hot topic in the cross-cutting areas of ophthalmology and imaging. Currently, ocular imaging with traditional optical coherence tomography (OCT) is limited in lateral resolution and thus can hardly resolve cellular structures. Conventional OCT technology obtains ultra-high resolution at the expense of a certain imaging range and cannot achieve full field of view imaging. In the early years, Time-domain full-field OCT (TD-FF-OCT) has been mainly used for ex vivo ophthalmic tissue studies, limited by the low speed and low full-well capacity of existing two-dimensional (2D) cameras. The recent improvements in system design opened new imaging possibilities for in vivo applications thanks to its distinctive optical properties of TD-FF-OCT such as a spatial resolution almost insensitive to aberrations, and the possibility to control the curvature of the optical slice. This review also attempts to look at the future directions of TD-FF-OCT evolution, for example, the potential transfer of the functional-imaging dynamic TD-FF-OCT from the ex vivo into in vivo use and its expected benefit in basic and clinical ophthalmic research. Through non-invasive, wide-field, and cellular-resolution imaging, TD-FF-OCT has great potential to be the next-generation imaging modality to improve our understanding of human eye physiology and pathology.

Ultrasound in ocular oncology: Technical advances, clinical applications, and limitations

Due to its accessibility and ability for real-time image acquisition of ocular structures, ultrasound has high utility in the visualization of the eye, especially in ocular oncology. In this minireview, we summarize the technical rationale and applications of ultrasound modalities, A-scan, B-scan, high-frequency ultrasound biomicroscopy (UBM), and Doppler measurement. A-scan ultrasound uses a transducer of 7-11 MHz, making it useful for determining the echogenicity of ocular tumors (7-8 MHz) and measuring the axial length of the eye (10-11 MHz). B-scan ultrasound operates at 10-20 MHz, which can be used for measuring posterior ocular tumors while UBM operates at 40-100 MHz to evaluate anterior ocular structures. Doppler ultrasonography allows for the detection of tumor vascularization. While ultrasonography has numerous clinical applications due to its favorable penetration compared with optical coherence tomography, it is still limited by its relatively lower resolution. Ultrasound also requires an experienced sonographer due to the need for accurate probe localization to areas of interest.

Anterior segment optical coherence tomography in ocular surface tumours and simulating lesions

This study aims to systematically review the reported literature on the use of anterior segment optical coherence tomography (AS-OCT) in ocular surface tumours and simulating lesions. A systematic literature search was done using PubMed, Scopus, and Web of Science databases between January 2002 and December 2021. On AS-OCT, ocular surface squamous neoplasia typically demonstrate epithelial thickening, epithelial hyperreflectivity, and an abrupt transition between normal and abnormal epithelium. Conjunctival nevi usually show mildly hyperreflective epithelium of normal thickness, internal hyperreflectivity, and intralesional cysts which is the hallmark of this tumour. Primary acquired melanosis presents with normal thickness epithelium, basal epithelial hyperreflectivity, and absence of cysts. Conjunctival melanoma demonstrates hyperreflective normal/thickened epithelium, hyperreflective basal epithelium, internal hyperreflectivity, and absence of intralesional cysts. Conjunctival lymphoma shows homogenous, low-medium reflective subepithelial lesions with smooth borders, and dot-like infiltrates. Benign reactive lymphoid hyperplasia findings are similar to lymphoma but the infiltrates are more hyperreflective compared to lymphoma. Pterygium shows thickened conjunctival epithelium, epithelial hyperreflectivity, and subepithelial wedge-shaped hyperreflective tissue separated from the overlying epithelium by a cleavage plane. Pinguecula demonstrates mildly thickened epithelium and similar findings with pterygium but does not extend beyond the corneal limbus. This review shows that AS-OCT, as a noninvasive tool, has potential uses in the differential diagnosis of ocular surface tumours and simulating lesions. Major limitations of AS-OCT include limited visualization of the posterior border of thick, keratinized, and pigmented tumours and lack of assessment of large conjunctival tumours in a single cut.

Clinical and Optical Coherence Tomography Comparison Between Ocular Surface Squamous Neoplasia and Squamous Metaplasia

PURPOSE

The purpose of this study was to compare the clinical characteristics and high-resolution optical coherence tomography (HR-OCT) findings between corneal squamous metaplasia and ocular surface squamous neoplasia (OSSN).

METHODS

A retrospective case-control study of 8 patients, 4 with histologically confirmed squamous metaplasia and 4 with histologically confirmed OSSN, who presented to the Miami Veterans Administration Medical Center and Bascom Palmer Eye Institute between 2016 and 2020 was performed. Clinical characteristics, HR-OCT findings, and pathology were evaluated and compared.

RESULTS

Four patients with squamous metaplasia and 4 with OSSN were evaluated. In the metaplasia group, 75% were male, 2 were White, and 2 were Black. In the OSSN group, all 4 were White males. All lesions were opalescent and occurred at the limbus; however, the borders were more smooth and rounded in the metaplastic lesions compared with OSSN. HR-OCT findings were indistinguishable between the 2 groups.

CONCLUSIONS

There is overlap in clinical characteristics and HR-OCT findings between corneal squamous metaplasia and OSSN, highlighting one limitation of HR-OCT. As such, if a corneal opacity has some but not all HR-OCT findings of OSSN, squamous metaplasia should also be considered. A biopsy may be indicated to further evaluate and guide treatment.

Medical treatment for ocular surface squamous neoplasia

Ocular surface squamous neoplasia (OSSN) is the most common non-melanocytic tumour of the ocular surface. Surgical excision with wide margins using the "no-touch" method was originally the most popular treatment for OSSN. However, in the past two decades, the use of topical medications for OSSN treatment has gained a reputation amongst ophthalmologists for being an effective alternative to surgical excision. Furthermore, technological advancements, such as those seen in high-resolution optical coherence tomography (HR-OCT) for the anterior segment, have facilitated the diagnosis and monitoring of OSSN. When selecting a topical agent, interferon alpha-2b (IFNα-2b) and 5-fluorouracil (5-FU) are two of the gentlest medications used for OSSN and are often considered first line therapies due to their high-resolution rates and mild side effect profiles. Mitomycin C (MMC), on the other hand, has a highly toxic profile; therefore, while effective, in our hands it is considered as a second-line treatment for OSSN if the other modalities fail. In addition, newer and less studied agents, such as immune checkpoint inhibitors, retinoic acid, aloe vera, and anti-vascular endothelial growth factor have anti-neoplastic properties and have shown potential for the treatment of OSSN. We enclose an updated literature review of medical treatments for OSSN.

Anterior segment optical coherence tomography characteristics of conjunctival papilloma as compared to papilliform ocular surface squamous neoplasia

PURPOSE

To describe the anterior segment optical coherence tomography (AS-OCT) appearance of conjunctival papilloma and identify differentiating features from papilliform ocular surface squamous neoplasia (OSSN).

METHOD

A retrospective chart review of individuals clinically diagnosed with conjunctival papilloma (n = 10) or papilliform OSSN (n = 10) based on slit lamp features. Data on demographics, tumour characteristics, and primary treatment were collected. AS-OCT features were assessed including epithelial thickness and reflectivity, a corrugated epithelial surface, presence of an overhanging edge, presence of intrinsic spaces and posterior shadowing. Histopathology was available in 5 papilloma and 3 OSSN specimens.

RESULT

Overall, the majority of individuals in both groups were white males. OSSN lesions were more likely to involve the limbus (80% vs.10%, p = 0.005) and the bulbar conjunctiva (100% vs. 20%, p < 0.001) compared to papillomas. On AS-OCT, maximum epithelial thickness was thicker in papilloma compared to OSSN (936 ± 533 vs. 637 ± 207 µm, p = 0.009). The feature that best differentiated papilloma from OSSN was an overhanging edge (100% vs. 0%, p < 0.001), where the epithelial lesion was seen on top of underlying normal epithelium. Other features more common in papilloma compared to OSSN included a corrugated epithelial surface (70% vs.10%, p = 0.02), the presence of intrinsic spaces (100% vs. 50%, p = 0.03), and posterior shadowing (100% vs. 40%, p = 0.01).

CONCLUSION

AS-OCT shows differentiating features between papilloma and OSSN with an overhanging edge as a distinctive AS-OCT feature of papilloma.

The Management of Ocular Surface Squamous Neoplasia (OSSN)

The rise of primary topical monotherapy with chemotherapeutic drugs and immunomodulatory agents represents an increasing recognition of the medical management of ocular surface squamous neoplasia (OSSN), which may replace surgery as the standard of care in the future. Currently, there is no consensus regarding the best way to manage OSSN with no existing guidelines to date. This paper seeks to evaluate evidence surrounding available treatment modalities and proposes an approach to management. The approach will guide ophthalmologists in selecting the most appropriate treatment regime based on patient and disease factors to minimize treatment related morbidity and improve OSSN control. Further work can be done to validate this algorithm and to develop formal guidelines to direct the management of OSSN.

Unilateral vortex keratopathy of unknown etiology

A 54-year-old man with noncontributory medical history presented to an ophthalmologist in January 2022 after 10 days of irritation in his right eye. The patient recounts having felt something get into his eye and under his contact lens (CL) while he was climbing into his car, but he was unsure what the foreign body may have been. Initial examination by the clinician found uncorrected distance visual acuity of 20/100-2 with a corneal abrasion, 4+ corneal edema, and 3+ conjunctival injection, for which he was placed on topical antibiotics (ocuflox and tobradex) with a bandage CL. 1 week later, visual acuity was 20/80, corneal edema had improved, and he was noted to have corneal scarring and an epithelial defect. Tobradex was continued while prednisolone drops and preservative-free artificial tears were started. 1 week later, the patient had worsening visual acuity to 20/250 and was referred to our tertiary center. On initial consultation, the patient had an uncorrected distance visual acuity of 20/500 and an uncorrected near visual acuity of >J10 in the right eye. Slitlamp examination of the right eye was significant for vortex keratopathy and mild corneal pannus with 360-degree subtle conjunctivalization of the limbus ( Figure 1JOURNAL/jcrs/04.03/02158034-202210000-00022/figure1/v/2022-10-03T121249Z/r/image-tiff ). The corneal topograph was obtained showing significant surface irregularity on the Placido image ( Figure 2JOURNAL/jcrs/04.03/02158034-202210000-00022/figure2/v/2022-10-03T121249Z/r/image-tiff ). Examination of the left eye was unremarkable. The ocular history is significant for myopia of -4.0 diopters and CL use for 20 years. The patient admits to regularly wearing soft CLs for several days straight and only removing them for a few hours. Antibiotics were discontinued, corticosteroid drops were reduced in frequency, and the patient was continued on preservative-free artificial tears. What imaging might you consider? What is your differential diagnosis at this point? What would be the most appropriate surgical and/or medical interventions? What would you counsel in prognosis for this patient?

Recent advances in optical coherence tomography for anterior segment imaging in small animals and their clinical implications

Anterior segment optical coherence tomography (AS-OCT) is a rapidly evolving area of OCT imaging, providing high-resolution and non-invasive volumetric imaging of the anterior segment. This review focuses on recent advances in AS-OCT imaging in small animals, which we categorize into ultrahigh-resolution, spectroscopic, magnetomotive, polarization-sensitive, and angiographic AS-OCTs. We summarize their technical foundations, review their applications to small animal imaging, and briefly discuss their current and future clinical applications.

Ocular Surface Squamous Neoplasia Masquerading as Recalcitrant Epithelial Keratitis

PURPOSE

The purpose of this study was to report a unique case of ocular surface squamous neoplasia that masqueraded as a nonresolving toxic epithelial keratitis.

METHODS

This was a case report and review of the literature.

RESULTS

A 79-year-old man presented with decreased vision, redness, and a foreign body sensation in his right eye that was refractory to treatment with lubrication and topical nonsteroidal antiinflammatory drops. Before presentation, the referring provider believed that he had medicamentosa-related keratitis and placed him on oral methazolamide. Slitlamp biomicroscopy of the right eye revealed diffuse epitheliopathy with punctate fluorescein staining and subtle underlying corneal epithelial opalescence. A mildly thickened and inflamed pinguecula was noted from 2 to 5 o'clock at the limbus of the right eye. An anterior segment high-resolution optical coherence tomography revealed thickened, hyperreflective epithelium with an abrupt transition. An incisional biopsy confirmed conjunctival and corneal intraepithelial neoplasia. The patient improved after 4 cycles of topical chemotherapy with 1% 5-fluorouracil eye drops with complete resolution of the corneal and conjunctival pathology.

CONCLUSIONS

Ocular surface squamous neoplasia can rarely masquerade as a recalcitrant medicamentosa and epithelial keratitis. In subtle cases or in cases with combined ocular surface morbidities, anterior segment high-resolution optical coherence tomography can be helpful to diagnose and direct therapy.

Reliability of Time Domain AS-OCT in Measuring the Extraocular Rectus Muscle Insertion-Limbus Distances: A Systematic Review and Meta-Analysis

Purpose

The insertion-limbus distances of the extraocular muscles are clinically relevant in the preoperative planning of strabismus surgeries, especially in reoperations when information regarding insertion sites is not accessible to the surgeon. In this systematic review, we assess the reliability of time-domain anterior segment optical coherence tomography (TD AS-OCT) in determining insertion-limbus distances preoperatively by investigating prior studies that compare preoperative TD AS-OCT measurements of the insertion-limbus distances to those of calipers, which are assumed to be the gold standard.

Methods

Systematically reviewing EMBASE, PubMed, Google Scholar, Science Direct, and Web of Science, 2 members screened for studies that compared preoperative TD AS-OCT measurements to those of intraoperative calipers, the gold standard. To assess the risk of bias for individual studies, the reviewers utilized the ROBINS-I tool, a Cochrane's collaboration tool used to assess bias in studies that are not randomized. For the meta-analysis, parallel forms reliability was examined and estimated as the Pearson product-moment correlation between TD AS-OCT measurements and surgical caliper measurements.

Results

Six out of the seven eligible studies provided measures of reliability that were >0.7. These six records were eligible for meta-analysis. There was no evidence of a difference between means of TD AS-OCT and caliper measurements ( = 6.81, 95% CI [6.41, 7.22]; = 6.73, 95% CI [6.18, 7.29]; = 0.08, 95% CI [-0.44, 0.61]). Reliability was estimated to be good ( = 0.91) though the lower limit was slightly below the recommended minimum acceptable level of 0.70 (95% CI [0.65, >0.99]).

Conclusion

In the setting of primary surgeries, TD AS-OCT has an acceptable reliability. However, there is insufficient data to conclude whether TD AS-OCT has an acceptable reliability in the setting of reoperations.

Topical pharmacotherapy for ocular surface squamous neoplasia: systematic review and meta-analysis

Ocular surface squamous neoplasia (OSSN) has different treatment modalities. Although surgical excision has been the gold standard therapeutic option, topical pharmacotherapy agents such as 5-fluorouracil (5-FU), interferon alfa-2b (IFN) and mitomycin-C (MMC) are also commonly used. The protocol was registered (CRD42021224961). Comprehensive literature research was carried out to compare topical pharmacotherapy (5-FU or IFN or MMC) to surgical excision regarding clinical success (tumor resolution), recurrence and complications in patients undergoing treatment for OSSN. From 7859 records, 7 articles were included in the qualitative and 4 in the quantitative synthesis. The outcomes of surgical excision and topical pharmacotherapy were comparable in the included articles. There were no significant differences between surgical excision and topical pharmacotherapy regarding the clinical success [odds ratio (OR): 0.785; confidence interval (CI): 0.130-4.736, P = 0.792)] and tumor recurrence (OR: 0.746; CI: 0.213-2.609; P = 0.646). The most common side effect of the different therapeutic options was dry eye. The highest rate of dry eye symptoms was reported after surgical excision (in 59%). Topical pharmacotherapy with all the 3 agents is as effective and well-tolerable as surgical excision in terms of tumor resolution, recurrence rate and side effects in all OSSN patients suggesting similar long-term clinical benefits.

Ocular Surface Squamous Neoplasia: A 12-Month Prospective Evaluation of Incidence in Waikato, New Zealand

Ocular surface squamous neoplasia (OSSN) has a high incidence in the southern hemisphere. This prospective study evaluated the incidence of OSSN in the Waikato region of New Zealand. All patients presenting with pterygium or conjunctival lesions in the Waikato region in 2020 were included. All surgeons in the region were asked to send all conjunctival and corneal specimens excised for histopathologic examination. The primary outcome measure was the incidence of OSSN. Eighty-eight percent of all excised specimens were sent for histopathologic examination. Of the 185 excised lesions sent for histopathological assessment, 18 (10%) were reported as OSSN. Patients were on average 69.4 years of age (standard deviation, SD = 6.9), predominantly male (78%), and of New Zealand-European ethnicity (89%). The OSSN annual incidence was 3.67/100,000/year. Histology grades included conjunctival intraepithelial neoplasia (CIN)-I (25%), CIN-II (25%), CIN-III (12.5%), carcinoma in situ (25%), and invasive squamous cell carcinoma (SCC) (12.5%). One patient with invasive SCC required exenteration. This study identified a high incidence rate of OSSN and is the first prospective study to analyze OSSN epidemiology in New Zealand.

Imaging of Uveal Melanoma—Current Standard and Methods in Development

Simple Summary

Uveal melanoma is the most prevalent intraocular tumor in adults, derived from melanocytes; the liver is the most common site of its metastases. Due to troublesome tumor localization, different imaging techniques are utilized in diagnostics, i.e., fundus imaging (FI), ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), positron emission tomography/computed tomography (PET/CT), magnetic resonance imaging (MRI), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), or fundus autofluorescence (FAF). Specialists eagerly use these techniques, but sometimes the precision and quality of the obtained images are imperfect, raising diagnostic doubts and prompting the search for new ones. In addition to analyzing the currently utilized methods, this review also introduces experimental techniques that may be adapted to clinical practice in the future. Moreover, we raise the topic and present a perspective for personalized medicine in uveal melanoma treatment.

Abstract

Uveal melanoma is the most common primary intraocular malignancy in adults, characterized by an insidious onset and poor prognosis strongly associated with tumor size and the presence of distant metastases, most commonly in the liver. Contrary to most tumor identification, a biopsy followed by a pathological exam is used only in certain cases. Therefore, an early and noninvasive diagnosis is essential to enhance patients’ chances for early treatment. We reviewed imaging modalities currently used in the diagnostics of uveal melanoma, including fundus imaging, ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), fundus autofluorescence (FAF), as well as positron emission tomography/computed tomography (PET/CT) or magnetic resonance imaging (MRI). The principle of imaging techniques is briefly explained, along with their role in the diagnostic process and a summary of their advantages and limitations. Further, the experimental data and the advancements in imaging modalities are explained. We describe UM imaging innovations, show their current usage and development, and explain the possibilities of utilizing such modalities to diagnose uveal melanoma in the future.

Topical Chemotherapy for Treating Ocular Surface Squamous Neoplasia with a Combination of Interferon α-2b and 5-Fluorouracil

Introduction

This study evaluated the efficacy of combined interferon α-2b (IFNα2b) and 5-fluorouracil (5-FU) as primary treatment for ocular surface squamous neoplasia (OSSN).

Methods

In this retrospective study, 27 eyes with OSSN followed by topical application of combined IFNα2b and 5-FU were examined. Reported outcome measures were tumor response, visual acuity, time to complete resolution, recurrence and treatment complications.

Results

Twenty-six patients (17 male, 9 female) had a mean age of 63.9 (median, 67; range 22–83) years. Complete tumor response was observed in 24 eyes (88.9%). Three eyes (11.1%) showed partial response to the chemotherapy agents and later underwent surgical tumor removal. The median time to complete resolution was 6 (mean, 6.1; range, 3–11) weeks. Of these, the patients received between one to three cycles of 5-FU therapy (median, 2; mean, 1.8). Complications noted were transient irritation at 5-FU cycle (11 eyes, 40.7%). There was no tumor recurrence at mean follow-up of 16.1 (median, 12; range 6–38) months.

Conclusions

Combination therapy of IFNα2b and 5-FU was a safe and effective treatment, inducing a short duration of administration and low recurrence rate for OSSN.

Trial Registration

Retrospectively registered, UHCT22048.

Role of AS-OCT in Managing Corneal Disorders

Optical coherence tomography (OCT) is analogous to ultrasound biometry in the cross sectional imaging of ocular tissues. Development of current devices with deeper penetration and higher resolution has made it popular tool in clinics for visualization of anterior segment structures. In this review, the authors discussed the application of AS-OCT for diagnosis and management of various corneal and ocular surface disorders. Further, recent developments in the application of the device for pediatric corneal disorders and extending the application of OCT angiography for anterior segment are introduced.

The use of high resolution optical coherence tomography (HR-OCT) in the diagnosis of ocular surface masqueraders

INTRODUCTION

Ocular surface masqueraders encompass any ocular surface lesion masquerading as another ocular surface lesion. High resolution optical coherence tomography (HR-OCT) has emerged as an adjunctive tool to clinical acumen. This study's purpose is to evaluate the utility of HR-OCT images in guiding the diagnosis and management of those lesions.

MATERIAL AND METHODS

22 individuals with a clinically ambiguous ocular surface lesion with slit lamp photographs (SLP), HR-OCT images, and histopathological examination were included in the study. The presumptive clinical diagnosis based on SLP was compared to the diagnosis suggested by HR-OCT findings and to definitive diagnosis by histopathology. The main outcome of this study was the frequency in which HR-OCT findings guided the clinician to the correct diagnosis.

RESULTS

7 lesions were epithelial, 3 had an epithelial and a subepithelial component, and 12 were subepithelial. HR-OCT was most effective in discerning lesion location, successfully identifying the location in 100% of cases. Classic HR-OCT findings were detected in 68.2% of cases while suggestive features were detected in 31.8% of cases. The epithelial lesions' mean epithelial thickness was 265.4 ± 140.6 μm, the subepithelial lesions' mean was 58.0 ± 25.0 μm, and the combined lesions' mean was 140.0 ± 70.0 μm. The epithelium was significantly thicker in epithelial lesions compared to subepithelial and combined lesions. By ROC analysis we identified that using a cut off of 156 μm, the sensitivity was 86% and the specificity was 93%.

DISCUSSION

HR-OCT can be a valuable diagnostic tool, assisting in the differentiation of ambiguous ocular surface pathologies by providing a cross-sectional, morphological image of the lesion.

Histopathological Rate of Ocular Surface Squamous Neoplasia in Clinically Suspected Pterygium Specimens: 10-Year Results

PURPOSE

The aim of this study was to evaluate the prevalence of histopathologically confirmed ocular surface squamous neoplasia (OSSN) in clinically diagnosed pterygium samples at a tertiary center in Northern California, over a 10-year period (2009-2019).

METHODS

A retrospective chart review of patients older than 18 years with clinically diagnosed benign pterygium requiring excision was conducted. Clinically suspected pterygia were excised using standard techniques and routinely submitted to the University of California Davis for pathologic evaluation. Demographic, clinical, surgical, and pathological information were recorded and analyzed. The prevalence rate of OSSN was calculated.

RESULTS

A total of 348 consecutive specimens were evaluated. The mean (±SD) age of the patients was 58 ± 12 years, with a near equal sex representation. A total of 57 (16%) pterygia were recurrent at initial presentation. Histopathologic results demonstrated a single case of OSSN. This patient did not have a documented history of carcinoma in other organs or any history of herpes virus, human papilloma virus, or human immunodeficiency virus infection.

CONCLUSIONS

The prevalence of histopathological OSSN in clinically suspected pterygia within our sample was approximately 0.3%. Because of shared clinical characteristics of pterygia and OSSN, a high index of suspicion and judicious use of anterior segment optical coherence tomography enable for effective preoperative diagnosis of OSSN. However, in the absence of clinical expertise or high-resolution optical coherence tomography, routine tissue pathologic examination may be warranted.

Histopathology-guided management of ocular surface squamous neoplasia with corneal stromal or scleral invasion using ruthenium-106 plaque brachytherapy

BACKGROUND/AIM

To evaluate the safety and efficacy of ruthenium-106 (Ru-106) plaque brachytherapy in managing invasive ocular surface squamous neoplasia (OSSN).

METHODS

This is a retrospective, non-comparative, interventional case series of 42 eyes with OSSN with histopathologically-proven corneal stromal and/or scleral invasion that underwent Ru-106 plaque brachytherapy. Main outcome measures were tumour regression, eye salvage, final visual acuity, treatment complications and metastasis.

RESULTS

At presentation, the mean tumour basal diameter was 9.3 mm (range 5-26 mm) and thickness 3.1 mm (range 1.5-11 mm). Prior treatment included excision biopsy in two patients (5%), incision biopsy and topical interferon in one each (2%). Following excision with 4 mm clinically clear margins, corneal stromal and/or scleral invasion of OSSN was confirmed in all 42 cases, with the excised base showing invasive squamous cell carcinoma. A total dose of 5000 cGy over a mean duration of 19.7 hours (range 7-41 hours) was provided to an axial depth of 2 mm using Ru-106 surface plaque. Over a mean follow-up of 36.9 months (range 22.3-72 months), complete tumour regression was achieved in all eyes (100%). Two eyes (5%) showed conjunctival tumour growth remote from the site of prior treatment. Visual acuity was maintained at ≥20/200 in 35 eyes (83%), with a loss of >2 Snellen lines in 1 eye (2%). There was no evidence of regional lymph node or systemic metastasis.

CONCLUSION

Histopathology-guided use of Ru-106 surface plaque brachytherapy is a safe and an effective adjuvant therapy in the management of corneal stromal and/or scleral invasion of OSSN.

Update on the Management of Ocular Surface Squamous Neoplasia

Purpose of review

To review and update the latest findings in diagnosis and management of ocular surface squamous neoplasia (OSSN).

Recent findings

OSSN is the most common anterior segment neoplastic disease process. Several ocular surface imaging techniques have been developed for the early diagnosis and management of clinical and subclinical ocular surface squamous neoplasia, including high-resolution optical coherence tomography (HR-OCT), in vivo confocal microscopy, and ultrasound biomicroscopy. Treatment modalities include both surgical and medical management, with a recent trend towards primary and adjunctive pharmacotherapy.

Summary

There is increasing use of HR-OCT for the diagnosis and monitoring of clinical and subclinical OSSN lesions. Topical pharmacotherapy agents, including interferon α-2b, 5-fluorouracil, and mitomycin C, have demonstrable efficacy in the treatment of OSSN and their use may be dictated based upon tumor factors, patient factors, cost, and side effect profile. Both surgical excision and adjunctive topical medications have excellent success, with the favored treatment method trending towards topical pharmacotherapy as primary therapy.

Case Series: High-resolution Optical Coherence Tomography as an Optical Biopsy in Ocular Surface Squamous Neoplasia

SIGNIFICANCE

Ocular surface squamous neoplasias are superficial tumors of the cornea and conjunctiva that can be sight threatening if neglected. Therefore, accurate noninvasive diagnostic modalities are needed.

PURPOSE

The purpose of this case series was to describe the hallmark features of ocular surface squamous neoplasia on high-resolution optical coherence tomography (HR-OCT) imaging and its use in the evaluation and management of superficial ocular tumors.

CASE SERIES

Five eyes of four patients with ocular surface squamous neoplasia are described. Whereas two eyes displayed the classic clinical features of ocular surface squamous neoplasia, three of the five eyes had more subtle atypical features. However, all shared features on HR-OCT of epithelial thickening and hyperreflectivity with abrupt transitions between normal and abnormal tissue, classic features of ocular surface squamous neoplasia. All lesions ultimately underwent incisional or excisional biopsy and were confirmed to be ocular surface squamous neoplasia on histopathology.

CONCLUSIONS

Ocular surface squamous neoplasia may present as a classic tumor but can also have subtle features or masquerade. Accurate methods to diagnose and manage patients with ocular surface squamous neoplasia are necessary. With recent advancements in technology, HR-OCT has been demonstrated to accurately identify ocular surface squamous neoplasia with the repeatable optical findings of (1) epithelial thickening, (2) epithelial hyperreflectivity, and (3) abrupt transition zone between normal and abnormal tissue. This case series demonstrates how HR-OCT can help provide an optical biopsy to guide appropriate diagnosis and management of this neoplastic lesion.

Spectrum of AS-OCT features of ocular surface tumors and correlation of clinico-tomographic features with histopathology: a study of 70 lesions

PURPOSE

To assess the correlation between clinical and anterior segment optical coherence tomographic (AS-OCT) details and histopathological changes in various ocular surface lesions.

METHODS

Prospective case series of 70 lesions in 65 patients.

RESULTS

AS-OCT revealed epithelial changes in OSSN (n = 19; 44%), squamous papilloma (n = 3; 60%), nevus (n = 1; 33%), epithelial hyperplasia (n = 1; 33%), granular dystrophy (n = 1; 100%) and granulation tissue (n = 1; 100%); subepithelial changes in chronic inflammation (n = 4, 100%), lymphoma (n = 3; 100%) and arteriovenous malformation (n = 1; 100%); combined epithelial and subepithelial changes in OSSN (n = 24; 56%), squamous papilloma (n = 2; 40%), PEH (n = 3; 100%), nevus (n = 2; 67%), epithelial hyperplasia (n = 2; 67%), solar elastosis (n = 1; 100%), lobular capillary hemangioma (n = 1; 100%) and sebaceous carcinoma (n = 1; 100%). Epithelial involvement on AS-OCT paralleled the histopathological findings in 98% (n = 69) and subepithelial involvement in 83% (n = 58). The correlation of clinico-tomographic diagnosis with histopathology diagnosis was seen in 77% (n = 54) lesions. Sensitivity and specificity of AS-OCT as a diagnostic tool for detection of epithelial involvement were 100% and 92% and for subepithelial involvement was 98% and 100%, respectively.

CONCLUSION

The correlation between AS-OCT and histopathology features determining epithelial and subepithelial involvement is excellent. It is a useful adjunctive tool for the diagnosis of ocular surface lesions.

The role of imaging technologies for ocular surface tumors

PURPOSE OF REVIEW

This review will discuss the utility of high-resolution anterior segment optical coherence tomography (HR-OCT), in-vivo confocal microscopy (IVCM) and ultrasound biomicroscopy (UBM) in characterizing and diagnosing various ocular surface tumors, namely ocular surface squamous neoplasia (OSSN), conjunctival lymphoma and conjunctival melanoma. The strengths and limitations of each imaging modality will be discussed along with the characteristics findings of each lesion on each imaging platform.

RECENT FINDINGS

HR-OCT can consistently be utilized in the clinic setting to distinguish between epithelial ocular surface tumors such as OSSN as compared with subepithelial tumors such as conjunctival lymphoma and conjunctival melanoma given their distinctive findings. IVCM can be used as an adjunct to HR-OCT to obtain cellular and surface characteristics, whereas UBM can be used to assess tumor depth and thickness for larger and highly pigmented lesions as well as to detect intraocular invasion.

SUMMARY

HR-OCT, IVCM and UBM are all helpful imaging modalities to diagnose and characterize various ocular surface tumors and can serve as valuable adjuncts to monitor treatment response and assess for recurrence ocular surface tumors.

The Value of Anterior Segment Optical Coherence Tomography in Different Types of Corneal Infections: An Update

Anterior segment optical coherence tomography (AS-OCT) is a modality that uses low-coherence interferometry to visualize and assess anterior segment ocular features, offering several advantages of being a sterile and noncontact modality that generates high-resolution cross-sectional images of the tissues. The qualitative and quantitative information provided by AS-OCT may be extremely useful for the clinician in the assessment of a wide spectrum of corneal infections, guiding in the management and follow-up of these patients. In clinical practice, infections are routinely evaluated with slit-lamp biomicroscopy, an examination and imaging modality that is limited by the physical characteristics of light. As a consequence, the depth of pathology and the eventually associated corneal edema cannot be accurately measured with the slit-lamp. Therefore, it represents a limit for the clinician, as in vivo information about corneal diseases and the response to treatment is limited. Resolution of corneal infection is characterized by an early reduction in corneal edema, followed by a later reduction in infiltration: both parameters can be routinely measured with standardized serial images by AS-OCT.

Ocular Oncology-Primary and Metastatic Malignancies

Several neoplastic processes can involve the eye, either primarily or secondary to a systemic malignancy. The most common primary tumors of the eye include conjunctival and uveal melanoma, retinoblastoma, conjunctival and intraocular lymphoma, and ocular surface squamous neoplasia. Metastatic spread from systemic malignancies, especially of the breast and lung, also can involve the eye. A combination of ophthalmologic examination, ancillary testing, and cytologic/histopathologic evaluation leads to accurate diagnosis. Management consists of surgery, radiotherapy, chemotherapy, and immunotherapy delivered in various forms.

Clinical role of swept source optical coherence tomography in anterior segment diseases: a review

PURPOSE

To note the comprehensive role of swept source anterior segment optical coherence tomography (SS-ASOCT) in anterior segment diseases.

METHODS

A systematic literature search was carried out on various medical databases using the keywords, swept source anterior segment optical coherence tomography; SS-ASOCT; Cornea and SS-ASOCT; SS-ASOCT and glaucoma; SS-ASOCT and cataract; SS-ASOCT and biometer; SS-ASOCT and tear film and ocular surface.Original works and novel reports describing the potential role of SS-ASOCT in various anterior segment conditions were included.

RESULTS

After a thorough assessment of literature, it was clear that the SS-ASOCT did provide newer insights into many anterior eye conditions. The rapid scan acquisition, deeper tissue penetration, and higher magnification did enhance many of our understandings, which were previously not possible. In addition, lenticular assessment under complex clinical scenarios with automated values on objective scale has made it a worthy tool with immense future possibilities.

CONCLUSIONS

SS-ASOCT unveiled various anterior segment findings which were of clinical importance.

Non-malignant conjunctival epithelial masses with ocular surface squamous neoplasia-like optical coherence tomography features

PURPOSE

To observe and describe the anterior segment optical coherence tomography features of limbally localised non-malignant epithelial mass lesions METHODS: Thirteen patients (age: 66.9 ± 16.3 years) with conjunctival mass suggesting ocular surface squamous neoplasia with biomicroscopic examination were imaged using anterior segment ocular coherence tomography (anterior segment optical coherence tomography)/Cirrus HD-OCT, Model 4000, Carl Zeiss Meditec, Inc., Dublin, CA, and Spectralis HRA + OCT system, Heidelberg Engineering, Vista, CA/. Cases with ocular surface squamous neoplasia-like anterior segment optical coherence tomography (hyperreflective, thickened epithelium and an abrupt transition from normal to abnormal) were included in the study. Maximal thickness of the epithelium was measured. Histological diagnosis was gained from an excisional or incisional biopsy or impression cytology specimens.

RESULTS

In six patients (age: 68.5 ± 15.4 years) with ocular surface squamous neoplasia-like anterior segment optical coherence tomography features, the histological diagnosis was other than ocular surface squamous neoplasia (papilloma, parakeratosis and a keratotic plaque with mild dysplasia), and ocular surface squamous neoplasia in seven cases (age: 65.6 ± 18.0 years). The maximal epithelial thickness was between 250 and 859 µm in non-ocular surface squamous neoplasia cases and between 252 and 596 µm in ocular surface squamous neoplasia cases.

CONCLUSION

Non-malignant epithelial lesions can mimic ocular surface squamous neoplasia on anterior segment optical coherence tomography.

Advances in Imaging Technology of Anterior Segment of the Eye

Advances in imaging technology and computer science have allowed the development of newer assessment of the anterior segment, including Corvis ST, Brillouin microscopy, ultrahigh-resolution optical coherence tomography, and artificial intelligence. They enable accurate and precise assessment of structural and biomechanical alterations associated with anterior segment disorders. This review will focus on these 4 new techniques, and a brief overview of these modalities will be introduced. The authors will also discuss the recent advances in research regarding these techniques and potential application of these techniques in clinical practice. Many studies on these modalities have reported promising results, indicating the potential for more detailed comprehensive understanding of the anterior segment tissues.

Long-Term Efficacy and Safety of Subconjunctival/Perilesional 5-Fluorouracil Injections for Ocular Surface Squamous Neoplasia

Purpose

To investigate the effectiveness and safety of subconjunctival/perilesional 5-fluorouracil injections on ocular surface squamous neoplasia (OSSN) during a 3-year follow-up period.

Patients and Methods

We followed up six patients with intraepithelial OSSN (in one eye each) that had regressed after subconjunctival/perilesional 5-fluorouracil injections. Conjunctival fluorescein angiography (FA) and indocyanine green angiography (ICGA), as well as anterior segment optical coherence tomography (AS-OCT), were performed to evaluate the OSSN status 3 years after initiation of treatment.

Results

The mean age of patients (five males, one female) at baseline was 62.3±11.6 years. The mean number of 5-fluorouracil injections was 17.0±8.6, with a mean treatment duration of 13.0±7.4 weeks. At the final visit, both intratumoral and conjunctival feeding vessels had disappeared on ICGA and FA, with no neovascularization-related leakage, in accordance with the results of AS-OCT. The period from complete tumor regression to final visit according to AS-OCT was 32.5±4.2 months, which was longer than that according to ICGA (31.3±3.2 months, p=0.034). The final best-corrected visual acuity was similar to that at baseline (p=0.128). No side effects were observed in any of the eyes.

Conclusion

Subconjunctival/perilesional 5-fluorouracil injections are an effective and safe treatment for OSSN. Future studies with a larger sample size are warranted for confirmation of our findings, as well as investigation into the reasons for residual areas of non-perfusion in the conjunctiva.