Pterygium and their management strategies:

Pterygium is a common ocular surface disease characterized by the abnormal growth of the bulbar conjunctiva and fibrovascular tissue that extends onto the cornea within the palpebral fissure area.

It is considered a proliferative ocular surface disorder, often affecting the conjunctival canthus, involving the hyperplasia of fibroblasts and neovascularization that progressively encroaches upon the cornea.

Signs & Symptoms of Pterygium:

• Eye irritation
• Worsening of corneal astigmatism
• Visual impairment
• Ocular motility disorders
• Refractive errors
• Redness
• FB sensation
• Excessive tearing
• Pain in eye

Causes/Pathogenesis:

• Abnormal Tissue Growth: Pterygium is characterized by the abnormal proliferation of the bulbar conjunctiva and fibrovascular tissue that extends onto the cornea.
• Similarities to Tumoral Tissues: Its pathological features, including cell proliferation, angiogenesis (new blood vessel formation), inflammation, and epithelial-mesenchymal transition (EMT), are very similar to those seen in tumoral tissues.
• Excessive Fibrous Tissue Proliferation: A common characteristic shared with other fibrous diseases (e.g., liver, renal, and pulmonary fibrosis) is the excessive proliferation of fibrous tissue.
• Epithelial-Mesenchymal Transition (EMT): EMT plays a pivotal role in pterygium development. This is a process where epithelial cells transform into mesenchymal-like cells, enhancing their ability to migrate, invade, and secrete extracellular matrix. This transformation can lead to epithelial cells becoming fibroblasts, which then promote the synthesis and deposition of extracellular matrix, potentially accelerating pterygium hyperplasia and invasion.
• TGF-β Signaling Pathway: The transforming growth factor beta (TGF-β) signaling pathway is significantly upregulated in pterygium. Elevated TGF-β levels are implicated in the excessive fibrotic response seen in pterygium fibroblasts.
• Circular RNAs (circRNAs): These non-coding RNA molecules have dysregulated expression in various disorders, including cancer, and play roles in cell differentiation, proliferation, angiogenesis, migration, and carcinogenesis.

Complications:

Recurrence after surgery: A notable recurrence rate of 0.57%–27.27% is observed post-surgical excision.

Surgical complications: These can include corneal scarring, symblepharon, ocular motility disorder, and corneal ulcers.

Treatment

1.Primary Treatment:

• Surgical excision is the main treatment for Pterygium.

2.Adjunctive Therapies (with surgery):

• Conjunctival autograft.
• Amniotic membrane transplantation.
• Antiproliferative drugs such as mitomycin C, cyclosporine, and bevacizumab.

3.Pharmacological Interventions (Emerging/Potential):

Nintedanib:

• This small molecule tyrosine kinase inhibitor has shown efficacy in halting TGF-β-induced EMT in retinal pigment epithelial cells and curbing excessive fibrosis in human Tenon’s capsule fibroblasts.
• It suppresses the proliferation of pterygium cells and enhances apoptosis by inhibiting the fibroblast growth factor receptor extracellular signal-regulated kinase signaling pathway.

Prognosis:

• High Recurrence Rate Pterygium has a notable recurrence rate after surgical removal, ranging from 0.57% to 27.27%, even with adjunctive therapies.
• Impact on Quality of Life This high recurrence rate contributes to “devastating effects on quality of life” for affected individuals.
• Need for New Treatments The persistent challenge of recurrence underscores an ongoing need for new non-surgical treatments aimed at inhibiting growth or preventing its return.
• Promising Outlook with New Therapies Emerging pharmacological interventions, such as nintedanib, show promise in reducing these recurrence rates, which could improve the overall prognosis by offering targeted treatment options that complement or lessen the need for surgery.

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