The slit-lamp image of the eye shown above demonstrates a triangular, vascularized growth extending from the nasal conjunctiva onto the cornea. Which of the following is the most likely diagnosis?

Explanation

## Image Findings * A **triangular, fleshy, vascularized growth** is observed originating from the nasal bulbar conjunctiva. * The growth **extends across the limbus onto the cornea**, with its apex pointing towards the pupil. * There is associated **corneal opacification** at the leading edge of the growth. * Prominent **feeder vessels** are visible within the lesion, indicating its vascular nature. ## Diagnosis **Key Point:** The image shows a **Pterygium**, characterized by a triangular, vascularized fibrovascular growth extending from the conjunctiva onto the cornea. A pterygium is a common ocular surface lesion, often associated with chronic exposure to ultraviolet (UV) light, dust, and wind. It typically originates from the nasal conjunctiva and grows towards the central cornea. The characteristic triangular shape, vascularization, and extension across the limbus onto the cornea are pathognomonic. The leading edge on the cornea can cause astigmatism and, if it reaches the visual axis, can impair vision. ## Differential Diagnosis | Feature | Pterygium | Pinguecula | Conjunctival Squamous Cell Carcinoma (SCC) | | :---------------------- | :---------------------------------------------- | :---------------------------------------------- | :---------------------------------------------- | | **Location/Extension** | Triangular, crosses limbus onto cornea | Yellowish, elevated, confined to conjunctiva | Irregular, gelatinous, nodular, or leukoplakic; can cross limbus | | **Vascularity** | Highly vascularized, prominent feeder vessels | Less vascularized, often avascular | Variable, can be vascularized | | **Shape** | Classic triangular shape | Oval or round | Irregular, papillomatous, or flat | | **Corneal Involvement** | Yes, invades cornea | No, does not invade cornea | Yes, can invade cornea | | **Symptoms** | Irritation, redness, foreign body sensation, astigmatism, vision loss (if central) | Mild irritation, cosmetic concern | Irritation, redness, foreign body sensation, vision loss, may ulcerate | ## Clinical Relevance **Clinical Pearl:** Pterygium is more common in individuals living in equatorial regions or those with outdoor occupations due to chronic UV exposure. Surgical excision is the primary treatment, often combined with adjunctive therapies like conjunctival autograft or mitomycin C to reduce recurrence rates. ## High-Yield for NEET PG **High-Yield:** Pterygium is a **degenerative and proliferative condition** of the conjunctiva and subconjunctival tissue, characterized by elastotic degeneration of collagen and fibrovascular proliferation. **Key Point:** The **Stocker's line**, an iron deposition line, is often seen at the leading edge of a pterygium on the cornea. ## Common Traps **Warning:** Do not confuse pterygium with pinguecula. A **pinguecula** is a yellowish, elevated lesion on the conjunctiva that **does not cross the limbus onto the cornea**. Pterygium, by definition, involves corneal invasion. ## Reference [cite:Kanski's Clinical Ophthalmology, 9th Edition, Chapter 4: Conjunctiva, Sclera, and Cornea]