NEET-PG 2013 Practice Questions

Q: In photophthalmia, which part of the eye is primarily affected?

Cornea. ***Cornea*** - **Photophthalmia** (also known as **snow blindness** or **arc eye**) is caused by overexposure to **ultraviolet (UV) light**, which primarily damages the **corneal epithelium**. - This damage leads to **superficial punctate keratitis**, characterized by pain, foreign body sensation, photophobia, and blurred vision. - Symptoms typically appear **6-12 hours after exposure** and resolve within **24-48 hours** with supportive care. *Retina* - The **retina** can be damaged by certain types of light (e.g., solar retinopathy from looking at the sun), but **UV light** in photophthalmia is largely absorbed by the anterior structures of the eye, particularly the cornea. - Retinal damage would typically present with **central visual loss** or **scotomas**, differing from the acute pain and photophobia of photophthalmia. *Optic nerve* - The **optic nerve** transmits visual information from the retina to the brain and is generally not directly affected by **UV light exposure** causing photophthalmia. - Optic nerve issues would manifest as severe **vision loss**, **pupillary abnormalities**, or **pain with eye movement**, which are not typical for photophthalmia. *Lens* - While chronic **UV exposure** can contribute to **cataract formation** in the lens over time, this is a long-term effect, not the acute primary damage seen in photophthalmia. - The acute presentation of photophthalmia with severe pain, photophobia, and foreign body sensation is characteristic of **corneal epithelial damage**, not lens involvement.

Q: Phlyctenular conjunctivitis is primarily associated with hypersensitivity to which of the following?

Staphylococcus. ***Staphylococcus*** - **Phlyctenular conjunctivitis** is characterized by delayed (Type IV) hypersensitivity reactions to bacterial antigens, most commonly from **Staphylococcus aureus**. - This condition often presents with small, nodular lesions (phlyctenules) on the conjunctiva or cornea, which are essentially collections of inflammatory cells responding to bacterial proteins. - **Important note**: **Mycobacterium tuberculosis** is another well-documented cause of phlyctenular conjunctivitis, particularly in TB-endemic regions, and should be considered in the differential diagnosis. - Other triggers include protein antigens from organisms colonizing the ocular surface. *Chlamydia* - While **Chlamydia trachomatis** can cause chronic conjunctivitis (e.g., trachoma, adult inclusion conjunctivitis), it does not typically lead to the distinct nodular lesions seen in phlyctenular conjunctivitis. - Ocular chlamydial infections are primarily characterized by follicular conjunctivitis and pannus formation. *Pneumococcus* - **Streptococcus pneumoniae** (Pneumococcus) is a common cause of acute bacterial conjunctivitis, characterized by purulent discharge and redness. - However, it is not associated with the specific delayed hypersensitivity reaction that defines phlyctenular conjunctivitis. *Aspergillus* - **Aspergillus** species are fungi and are more commonly implicated in fungal keratitis or allergic bronchopulmonary aspergillosis, particularly in immunocompromised individuals. - Fungal infections of the conjunctiva are rare and do not typically manifest as phlyctenular conjunctivitis.

Q: Schwalbe's ring is seen in which layer of the cornea?

Descemet's membrane. ***Descemet's membrane*** - Schwalbe's ring is a circular opacity representing the termination of **Descemet's membrane** at the periphery of the cornea, just anterior to the **trabecular meshwork**. - Its presence is a normal anatomical variant, but prominence can be associated with certain conditions like **posterior embryotoxon**. *Bowman's membrane* - This layer is found immediately beneath the **corneal epithelium** and does not extend to form Schwalbe's ring. - It is an acellular layer composed of collagen fibrils randomly arranged, offering resistance to infection and injury. *Stroma* - The stroma is the thickest layer of the cornea, composed primarily of **collagen lamellae** arranged in a highly organized manner. - It lies posterior to Bowman's membrane and anterior to Descemet's membrane, but its termination does not form Schwalbe's ring. *Substantia propria* - This is another name for the **corneal stroma**, which, as elaborated above, does not form Schwalbe's ring. - It comprises about 90% of the corneal thickness and provides the cornea's structural integrity and transparency.

Q: Scissor reflex is seen in ?

Keratoconus. ***Keratoconus*** - The **scissor reflex**, or **scissoring reflex**, is a characteristic finding during **retinoscopy** in patients with **keratoconus**. - It is caused by the irregular and variable refractive power across the cornea, leading to a distorted red reflex that appears to split into two bands moving in opposite directions. *Open angle glaucoma* - **Open-angle glaucoma** is characterized by progressive damage to the **optic nerve** and visual field loss, typically with a normal open anterior chamber angle. - It does not involve abnormalities in corneal shape or light refraction that would produce a scissor reflex during retinoscopy. *Phlyctenular conjunctivitis* - **Phlyctenular conjunctivitis** is an inflammatory condition characterized by small nodular lesions (phlyctenules) on the conjunctiva or cornea, often associated with a hypersensitivity reaction to microbial antigens. - This condition primarily affects the surface of the eye and does not cause the corneal ectasia or irregular astigmatism seen in keratoconus. *Interstitial keratitis* - **Interstitial keratitis** is an inflammation of the corneal stroma without significant involvement of the epithelium or endothelium, often associated with systemic infections like syphilis or Lyme disease. - While it can cause corneal opacification and vision loss, it typically does not lead to the conical shape or irregular astigmatism characteristic of keratoconus, which produces the scissor reflex.

Q: Non-sterile hypopyon is seen in ?

Fungal infection. ***Fungal infection*** - **Fungal keratitis** produces a **non-sterile hypopyon**, meaning the hypopyon contains actual fungal elements and organisms, not just inflammatory cells alone. - This is characteristically seen with **filamentous fungi** (Aspergillus, Fusarium) and yeast (Candida), which can directly invade the anterior chamber. - The hypopyon is typically **indolent, greyish-white, and does not shift with position** unlike bacterial hypopyon, and shows poor response to antibacterial therapy. - **Fungal culture and KOH mount** are diagnostic. *Pneumococcal infection* - **Bacterial keratitis** caused by *Streptococcus pneumoniae* produces a **sterile hypopyon** consisting purely of inflammatory cells (polymorphonuclear leukocytes) without organisms in the anterior chamber. - Presents with **acute onset, severe pain, and rapid progression** with a dense stromal infiltrate. - The hypopyon is **white, mobile, and shifts with head position**. *Pseudomonas aeruginosa infection* - **Pseudomonas keratitis** causes an aggressive infection with a **sterile hypopyon** due to intense inflammatory response. - Characterized by **rapidly progressive stromal necrosis** with a ground-glass appearance and greenish discharge. - Often associated with **contact lens wear** and can lead to corneal perforation within 24-48 hours. *Gonococcal conjunctivitis* - **Neisseria gonorrhoeae conjunctivitis** causes severe **hyperacute purulent conjunctivitis** with copious discharge. - Typically does **not cause hypopyon** unless there is secondary corneal ulceration leading to keratitis or endophthalmitis. - Primary manifestation is conjunctival inflammation, chemosis, and lid edema.

Q: Ameboid ulcers are primarily associated with which type of corneal ulcer?

Acanthamoeba corneal ulcer. ***Acanthamoeba corneal ulcer*** - **Acanthamoeba** infections are classically associated with **ameboid ulcers** due to the movement and destructive nature of this protozoan. - This type of ulcer often presents with severe pain, disproportionate to clinical findings, and can have a **ring infiltrates** appearance. *Fungal corneal ulcer* - Fungal ulcers typically present with a **feathery border** and satellite lesions, not ameboid shapes. - They are often associated with a history of **ocular trauma** involving plant material. *Herpetic corneal ulcer* - Herpetic ulcers are characterized by a **dendritic pattern** (tree-branch-like), which is distinct from an ameboid shape. - They are caused by the **herpes simplex virus** and can lead to recurrent episodes. *Bacterial corneal ulcer* - Bacterial ulcers typically present as a **round or oval infiltrate** with stromal edema and an overlying epithelial defect. - They can progress rapidly and are not described as having an **ameboid configuration**.

Q: Keratitis in contact lens wearers is caused by all except?

Pneumococcus. ***Pneumococcus*** - While *Streptococcus pneumoniae* (Pneumococcus) can cause bacterial keratitis, it is **classically associated with corneal ulcers following trauma** rather than contact lens wear. - In contact lens-related keratitis, Pneumococcus is **significantly less common** compared to *Pseudomonas*, which dominates as the primary bacterial pathogen in this setting. - Pneumococcal keratitis typically presents with a **well-demarcated, dense purulent ulcer with hypopyon**, often following corneal injury. *Pseudomonas* - **_Pseudomonas aeruginosa_** is **the most common cause of bacterial keratitis in contact lens wearers**, accounting for the majority of severe cases. - It thrives in moist environments such as contaminated contact lens cases and solutions, producing **exotoxins and proteases that cause rapid corneal destruction and tissue melt**. - Presents with a **rapidly progressive, dense stromal infiltrate** with a characteristic **ground-glass appearance** and potential for perforation. *Aspergillus* - **_Aspergillus_ species** are an important cause of **fungal keratitis**, particularly associated with contact lens wear, poor lens hygiene, and contaminated lens solutions. - Fungal keratitis presents with **feathery-edged infiltrates, satellite lesions**, and ring-shaped infiltrates, often requiring antifungal therapy. - More common in tropical climates and agricultural settings. *Chlamydia* - **_Chlamydia trachomatis_** is primarily a cause of **trachoma** (chronic follicular conjunctivitis leading to scarring) and **adult inclusion conjunctivitis**. - While it can cause **superficial punctate keratitis and pannus formation** in trachoma, it is **NOT a typical cause of acute suppurative keratitis in contact lens wearers**. - The acute bacterial and fungal keratitis seen in contact lens wearers is a different clinical entity from chlamydial conjunctivitis/keratopathy.

Q: What is the most common infection in contact lens users?

Pseudomonas. ***Pseudomonas*** - **Pseudomonas aeruginosa** is the leading cause of **bacterial keratitis** in contact lens wearers, accounting for 60-70% of culture-positive cases - This bacterium can **adhere to lenses**, form **biofilms**, and thrive in moist lens storage cases - Can cause rapid and severe corneal damage with **corneal ulceration**, potentially leading to **vision loss** *Staphylococcus* - **Staphylococcus aureus** and **Staphylococcus epidermidis** are common commensals of the skin and can cause eye infections, including keratitis and blepharitis - However, in the context of contact lens-related keratitis, **Pseudomonas aeruginosa** remains the primary pathogen for severe corneal infections *Streptococcus* - While various **Streptococcus species** (especially S. pneumoniae) can cause bacterial keratitis, they are less commonly associated with contact lens-related keratitis compared to Pseudomonas - **Streptococcal keratitis** typically occurs in non-contact lens wearers or after trauma *Neisseria* - **Neisseria gonorrhoeae** can cause hyperacute bacterial conjunctivitis with severe purulent discharge, but is not the most common cause of contact lens-related keratitis - **Neisseria meningitidis** can rarely cause conjunctivitis, but these infections usually indicate specific exposure or systemic disease

Q: The immune ring is a feature associated with which condition?

Fungal corneal ulcer. ***Fungal corneal ulcer*** - The **immune ring** (also known as a **Wessely ring**) is a characteristic sign seen in **fungal corneal ulcers**, particularly those caused by filamentous fungi. - It represents a **circumferential infiltrate** of immune cells and antigen-antibody complexes. *Interstitial keratitis* - Characterized by **stromal inflammation** without primary involvement of the epithelium or endothelium, often leading to ghost vessels after treatment. - It is typically associated with conditions like **syphilis** or other systemic infections, not an immune ring. *Bacterial corneal ulcer* - Often presents with a **rapidly progressing** corneal infiltrate, significant pain, and sometimes **hypopyon**. - While an immune response occurs, it does not typically form a distinct, well-defined **immune ring** like in fungal infections. *Herpes simplex keratitis* - Classically manifests as a **dendritic ulcer** or geographic ulcer, which can progress to stromal keratitis. - The immune ring is **not a feature** of herpes simplex keratitis; distinctive patterns like dendrites or disciform keratitis are seen.

Question 1

All statements are true about trachoma except:

Accepted Answer

Marked papillary hyperplasia with limbal follicles are seen in stage III

Answer

Strains mainly responsible are A, B, Ba and C

Answer

Trachoma is caused by bedsonian organism of psittacosis - lymphogranuloma - trachoma (PLT) group.

Answer

Corneal ulceration is a complication

Question 2

In photophthalmia, which part of the eye is primarily affected?

Accepted Answer

Cornea

Answer

Lens

Answer

Retina

Answer

Optic nerve

Question 3

Phlyctenular conjunctivitis is primarily associated with hypersensitivity to which of the following?

Accepted Answer

Staphylococcus

Answer

Chlamydia

Answer

Pneumococcus

Answer

Aspergillus

Question 4

Schwalbe's ring is seen in which layer of the cornea?

Accepted Answer

Descemet's membrane

Answer

Bowman's membrane

Answer

Stroma

Answer

Substantia propria

Question 5

Scissor reflex is seen in ?

Accepted Answer

Keratoconus

Answer

Open angle glaucoma

Answer

Phlyctenular conjunctivitis

Answer

Interstitial keratitis

Question 6

Non-sterile hypopyon is seen in ?

Accepted Answer

Fungal infection

Answer

Pneumococcal infection

Answer

Pseudomonas aeruginosa infection

Answer

Gonococcal conjunctivitis

Question 7

Ameboid ulcers are primarily associated with which type of corneal ulcer?

Accepted Answer

Acanthamoeba corneal ulcer

Answer

Fungal corneal ulcer

Answer

Bacterial corneal ulcer

Answer

Herpetic corneal ulcer

Question 8

Keratitis in contact lens wearers is caused by all except?

Accepted Answer

Pneumococcus

Answer

Chlamydia

Answer

Aspergillus

Answer

Pseudomonas

Question 9

What is the most common infection in contact lens users?

Accepted Answer

Pseudomonas

Answer

Streptococcus

Answer

Staphylococcus

Answer

Neisseria

Question 10

The immune ring is a feature associated with which condition?

Accepted Answer

Fungal corneal ulcer

Answer

Interstitial keratitis

Answer

Bacterial corneal ulcer

Answer

Herpes simplex keratitis

NEET-PG 2013

Ophthalmology