Use of High-Resolution Optical Coherence Tomography in the Surgical Management of Ocular Surface Squamous Neoplasia: A Pilot Study

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.

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.

Safety and efficacy of topical interferon alpha 2B and mitomycin C for localized conjunctival intraepithelial neoplasia: long-term report of their pharmacological safety and efficacy

PURPOSE

Ocular surface squamous neoplasia (OSSN) comprises a wide spectrum of squamous tumors, from which corneal/conjunctival intraepithelial neoplasia (CIN) is the most common one. The classic treatment is complete excision, but recurrence rates are high. Antineoplastic drugs such as mitomycin C (MMC) and interferon alpha 2b (IFNα2b) have been used as adjuvants or as primary treatment. To evaluate the efficacy and safety of topical IFNα2b and MMC in patients with CIN, a phase IIb double-blind clinical trial was performed.

METHODS

Patients diagnosed with localized CIN were evaluated by slit lamp and impression cytology and were randomly given MMC 0.04% or INF2b (1 million IU/mL) 4 times daily until neoplasia resolution. Time of resolution and frequency of adverse effects were analyzed to determine the pharmacological efficacy and safety of both medications.

RESULTS

Seventeen patients were included. Nine patients were treated with MMC and 8 with IFNα2b. All patients responded to treatment. The resolution time in days was 59.11 ± 24.02 in patients treated with MMC and 143.50 ± 47.181 in those treated with IFNα2b (p < 0.001). In the MMC group, one recurrence was reported (11%). There were no recurrences at 2 years of follow-up in the IFNα2b group. Regarding adverse effects, one or more mild adverse reaction occurred in 77% of patients managed with MMC and in 50% of patients managed with IFNα2b (p > 0.05). No serious adverse effects were reported.

CONCLUSIONS

Topical chemotherapy with MMC and IFNα2b demonstrate pharmacological safety and efficacy. Therefore, these drugs could be considered as primary therapies for localized CIN .

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.

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.

Ocular surface squamous neoplasia in Northern Thailand: a 16-year review

Purpose

To evaluate clinical characteristics, treatments, and outcomes in patients with ocular surface squamous neoplasia (OSSN) at a tertiary center in Northern Thailand.

Methods

Patients diagnosed with either corneal-conjunctival intraepithelial neoplasia (CIN) or squamous cell carcinoma (SCC) from May 2000 to December 2015, were recruited. The patients’ demographics, symptoms, clinical characteristics, cytopathology, treatments, and outcomes were reviewed.

Results

Overall 171 eyes from 168 patients, 92 eyes were CIN and 79 eyes were SCC. Males were affected in 65.5%. The mean age was 58.8 ± 16.8 (29–99) years. In most cases (60.3%), the tumors were located at the limbus. The most common clinical characteristic was papilliform appearance (46.2%). Human immunodeficiency virus (HIV) infection was found in 37 (22.0%) patients with a mean age of 40.5 ± 7.7 years. The treatments and outcomes were evaluated in 136 eyes whose main initial treatment was wide excision with adjunctive cryotherapy (47.8%), followed by topical mitomycin C (30.9%). The mean follow-up time after treatment was 20.8 ± 2.2 (3–110) months and the recurrence occurred in 18 eyes (13.2%) during the follow-up period. The mean recurrence-free time (months) for CIN was significantly longer than that of SCC (81.3 ± 10.0 [95%CI 61.5 – 101.1] vs 33.2 ± 4.6 [95%CI 24.0 – 42.3], p = 0.030). SCC was the only significant risk factor that influences the recurrence of the tumors with the adjusted hazard ratio of 5.69 (p = 0.005).

Conclusion

OSSN in Northern Thailand usually involved a limbal area and presented as a papilliform mass. HIV infection should be suspected in young patients. CIN had better outcomes after treatments than invasive SCC.

Management of ocular surface squamous neoplasia: Bowman Club Lecture 2021

The gold-standard treatment for ocular surface squamous neoplasia (OSSN) has traditionally been surgical excision with wide margins and a no-touch technique. However, surgery may be associated with several unfavourable sequelae, as well as significant recurrence rates if margins are positive. In recent years, topical chemotherapy with 5-fluorouracil, interferon α-2b and mitomycin C have emerged as valuable agents capable of effectively treating OSSN with varying adverse effects. These medical treatment options usually present additional costs to the patient but can allow patients to avoid surgery with fewer long-term effects. Anterior segment high-resolution optical coherence tomography is an excellent tool for diagnosing and monitoring OSSN and can be a useful aid for both surgical and medical treatments of OSSN.

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.

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.

High-Resolution Optical Coherence Tomography Angiography Characteristics of Limbal Stem Cell Deficiency

This study aimed to identify the anterior segment high-resolution optical coherence tomography (HR-OCT) and HR-OCT angiography (HR-OCTA) features suggestive of limbal stem cell deficiency (LSCD) as confirmed by both impression cytology (IC) and in vivo confocal microscopy (IVCM). This was a single-centre prospective cross-sectional study including 24 eyes of 22 patients with clinical suspicion of LSCD based on peripheral superficial corneal vascularisation and scarring. On IC and IVCM, performed and interpreted by blinded observers, 12 eyes each were diagnosed with and without LSCD. Additionally, 10 eyes of 5 healthy volunteers with no ocular pathology were also imaged. The 136 HR-OCT/A images of these 34 eyes were analysed with respect to 12 imaging parameters; the parameters most suggestive of LSCD were identified and the sensitivity and specificity were calculated. In the LSCD group, the most common aetiology was ocular chemical burns (83%), whereas in the non-LSCD group, the most common aetiology was viral keratitis (67%). Multiple logistic regression analysis revealed that mean epithelial reflectivity, mean stromal reflectivity, and mean superficial vascular density were the parameters that were diagnostic of LSCD on HR-OCT/A (p < 0.0001). A ratio of the mean epithelial reflectivity to stromal reflectivity of >1.29 corresponded with a high sensitivity (91.7%) and specificity (98.75%); while a mean superficial vascular density score of >0.38 corresponded with a sensitivity of 97.9% and specificity of 73.8%. In conclusion, HR-OCT/A as a non-invasive imaging modality could prove to be a useful tool for confirming the diagnosis of LSCD, with potential clinical and research applications.

Ocular surface squamous neoplasia: management and outcomes

Ocular surface squamous neoplasia (OSSN) is the most common ocular tumour with an incidence ranging from 0.03 to 1.9 per 100,000 persons/year. The diagnosis is made on clinical suspicion and confirmed with anterior-segment optical coherence tomography (AS-OCT), cytology, or histology. The purpose of this review is to provide an overview of the management options available for OSSN and review their success and recurrence rates. Surgery is the gold standard for the management of small OSSN lesions. With the increased use of less invasive diagnostic modalities such as AS-OCT and cytology, there has been a move to use topical therapies for the management of OSSN. The most commonly used agents are interferon-α2b (IFN), mitomycin-C (MMC) and 5-fluorouracil (5FU). They have been shown to have similar resolution and recurrence rates but differ in cost and side effect profile. IFN has the lowest side effect profile, but is also the most expensive, whereas MMC has the greatest surface toxicity and is priced midway between the three. 5FU is the cheapest of the three topical agents with less surface toxicity than MMC. Radiotherapy is mostly employed as adjuvant therapy. Newer novel therapies are available but have not been widely adopted as mainstream therapy due to cost and lack of clinical evidence. OSSN has the benefit of many management options. No single modality has been shown to superior and some patients will need the use of combination therapy to achieve an optimal clinical outcome.

Intraoperative optical coherence tomography in anterior segment surgery

Intraoperative optical coherence tomography (iOCT) enables real-time visualization of ocular structures during surgery and enhances our understanding of intraoperative dynamics. iOCT aids in decision-making during various anterior segment surgeries, and its efficacy and feasibility in anterior lamellar keratoplasty and endothelial keratoplasty is well established. The landmark DISCOVER study observed that iOCT altered the surgeon decision in 38% of cases undergoing lamellar keratoplasty and provided guidance regarding the need for secondary surgical intervention. iOCT also finds an application in phacoemulsification wherein it helps to assess corneal incisions, intralenticular pressure, and posterior capsule integrity during nuclear emulsification. iOCT aids in the visualization of angle structures during placement of tubes and shunts in glaucoma surgeries and allows precise creation of partial thickness scleral flaps. In addition, iOCT helps in establishing a diagnosis, as well as provide intraoperative guidance, in pediatric patients who are not cooperative for examination. The role of iOCT in refractive surgeries and ocular surface disorders is increasingly being evaluated. The limitations of present-day iOCT systems are related to instrument compatibility, automated tracking of the surgical field, and on-table volumetric analysis of the real-time images. Technological advances may facilitate complete integration of OCT in the surgical microscopes for all surgical procedures.