Update on conjunctival pathology

Macrophage Activation in Follicular Conjunctivitis during the COVID-19 Pandemic

Among the symptoms of SARS-CoV-2, follicular conjunctivitis has become relevant. The conjunctiva acts as an open lymph node, reacting to the viral antigen that binds the epithelial cells, forming follicles of B cells with activated T cells and NK cells on its surface, which, in turn, talk to monocyte-derived inflammatory infected macrophages. Here, the NLRP3 inflammasome is a major driver in releasing pro-inflammatory factors such as IL-6 and caspase-1, leading to follicular conjunctivitis and bulbar congestion, even as isolated signs in the 'asymptomatic' patient.

Oxidative Stress in the Anterior Ocular Diseases: Diagnostic and Treatment

The eye is a metabolically active structure, constantly exposed to solar radiations making its structure vulnerable to the high burden of reactive oxygen species (ROS), presenting many molecular interactions. The biomolecular cascade modification is caused especially in diseases of the ocular surface, cornea, conjunctiva, uvea, and lens. In fact, the injury in the anterior segment of the eye takes its origin from the perturbation of the pro-oxidant/antioxidant balance and leads to increased oxidative damage, especially when the first line of antioxidant defence weakens with age. Furthermore, oxidative stress is related to mitochondrial dysfunction, DNA damage, lipid peroxidation, protein modification, apoptosis, and inflammation, which are involved in anterior ocular disease progression such as dry eye, keratoconus, uveitis, and cataract. The different pathologies are interconnected through various mechanisms such as inflammation, oxidative stress making the diagnostics more relevant in early stages. The end point of the molecular pathway is the release of different antioxidant biomarkers offering the potential of predictive diagnostics of the pathology. In this review, we have analysed the oxidative stress and inflammatory processes in the front of the eye to provide a better understanding of the pathomechanism, the importance of biomarkers for the diagnosis of eye diseases, and the recent treatment of anterior ocular diseases.

Conjunctival Lesions: A 5-Year Basic Demographic Data and Clinicopathological Review in a Tertiary Eye Care Hospital

Background

Conjunctival lesions are common with a wide spectrum of benign, premalignant, and malignant lesions. Few histopathological studies have been conducted on conjunctival lesions with variable designs and results. Our aim in this study is to provide information on common conjunctival lesions seen in an ophthalmology tertiary care center in Saudi Arabia.

Methods

A retrospective, observational study of all consecutive conjunctival tissue specimens sent for histopathological assessment to the pathology department from 2015 to 2019 were analyzed. Clinical data were collected from medical records, and the histopathological slides were reviewed by a single pathologist.

Results

A total of 110 conjunctival specimens from 108 patients were included (mean age: 53 years, 67 males and 43 females). Bilateral involvement was mostly found in inflammatory lesions (40%). Most lesions were benign (91%), with a significantly longer duration of symptoms in malignant lesions (p = 0.036*). The clinical diagnosis matched the final histopathological diagnosis in 75.5% of the total specimens. The most frequent category of benign lesions was fibrodegenerative and proliferative lesions (53.6%), with a significantly higher prevalence among adult males (p < 0.001). Melanocytic lesions were more common in children (33.3%) than adults (9.8%), and the mean age of children was significantly lower (p = 0.013). The most frequent malignant lesion was ocular surface squamous neoplasia (50%), with equal prevalence among males and females. The overall outcome was favorable in 89.4% and unfavorable in 10.6%, mostly due to surgical complications, further progression of the lesion, or recurrence.

Conclusion

This study shows variability in the frequency of conjunctival lesions based on gender, age, geographical, racial, and environmental factors. There has been a shift in the gender-based prevalence of ocular squamous neoplasia over the last three decades, probably due to a change in lifestyle.

Transcriptome Analysis of Pterygium and Pinguecula Reveals Evidence of Genomic Instability Associated with Chronic Inflammation

Solar damage due to ultraviolet radiation (UVR) is implicated in the development of two proliferative lesions of the ocular surface: pterygium and pinguecula. Pterygium and pinguecula specimens were collected, along with adjacent healthy conjunctiva specimens. RNA was extracted and sequenced. Pairwise comparisons were made of differentially expressed genes (DEGs). Computational methods were used for analysis. Transcripts from 18,630 genes were identified. Comparison of two subgroups of pterygium specimens uncovered evidence of genomic instability associated with inflammation and the immune response; these changes were also observed in pinguecula, but to a lesser extent. Among the top DEGs were four genes encoding tumor suppressors that were downregulated in pterygium: C10orf90, RARRES1, DMBT1 and SCGB3A1; C10orf90 and RARRES1 were also downregulated in pinguecula. Ingenuity Pathway Analysis overwhelmingly linked DEGs to cancer for both lesions; however, both lesions are clearly still benign, as evidenced by the expression of other genes indicating their well-differentiated and non-invasive character. Pathways for epithelial cell proliferation were identified that distinguish the two lesions, as well as genes encoding specific pathway components. Upregulated DEGs common to both lesions, including KRT9 and TRPV3, provide a further insight into pathophysiology. Our findings suggest that pterygium and pinguecula, while benign lesions, are both on the pathological pathway towards neoplastic transformation.