Scissor reflex is seen in ?
Non-sterile hypopyon is seen in ?
Ameboid ulcers are primarily associated with which type of corneal ulcer?
Keratitis in contact lens wearers is caused by all except?
What is the most common infection in contact lens users?
The immune ring is a feature associated with which condition?
Reis-Buckler dystrophy affects which layer of the cornea?
Which of the following statements about Fuchs' corneal dystrophy is incorrect?
Corneal sensations are decreased in all of the following conditions except:
Normal level of visual acuity is attained at which age
NEET-PG 2013 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 21: Scissor reflex is seen in ?
- A. Open angle glaucoma
- B. Phlyctenular conjunctivitis
- C. Keratoconus (Correct Answer)
- D. Interstitial keratitis
Explanation: ***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.
Question 22: Non-sterile hypopyon is seen in ?
- A. Fungal infection (Correct Answer)
- B. Pneumococcal infection
- C. Pseudomonas aeruginosa infection
- D. Gonococcal conjunctivitis
Explanation: ***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.
Question 23: Ameboid ulcers are primarily associated with which type of corneal ulcer?
- A. Fungal corneal ulcer
- B. Acanthamoeba corneal ulcer (Correct Answer)
- C. Bacterial corneal ulcer
- D. Herpetic corneal ulcer
Explanation: ***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**.
Question 24: Keratitis in contact lens wearers is caused by all except?
- A. Chlamydia
- B. Aspergillus
- C. Pseudomonas
- D. Pneumococcus (Correct Answer)
Explanation: ***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.
Question 25: What is the most common infection in contact lens users?
- A. Streptococcus
- B. Staphylococcus
- C. Neisseria
- D. Pseudomonas (Correct Answer)
Explanation: ***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
Question 26: The immune ring is a feature associated with which condition?
- A. Interstitial keratitis
- B. Bacterial corneal ulcer
- C. Herpes simplex keratitis
- D. Fungal corneal ulcer (Correct Answer)
Explanation: ***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 27: Reis-Buckler dystrophy affects which layer of the cornea?
- A. Stroma
- B. Bowman's membrane (Correct Answer)
- C. Endothelium
- D. Epithelium
Explanation: ***Bowman's membrane*** - **Reis-Buckler dystrophy** is a type of corneal dystrophy specifically characterized by the progressive destruction and irregular regeneration of **Bowman's membrane** and the superficial stroma. - This leads to the formation of an abnormal fibrous layer that causes recurrent corneal erosions and significant visual impairment due to corneal opacification. *Epithelium* - While patients often experience recurrent **corneal erosions** involving the epithelium, the primary pathology in Reis-Buckler dystrophy affects the underlying Bowman's membrane. - The epithelial damage is secondary to the irregular surface created by the diseased Bowman's layer. *Stroma* - The **stroma** can be secondarily affected with superficial scarring and opacification in Reis-Buckler dystrophy, but the initial and primary site of pathology is Bowman's membrane. - Other dystrophies, such as macular or granular dystrophies, primarily involve the corneal stroma. *Endothelium* - The **endothelium** is not directly affected in Reis-Buckler dystrophy. - Endothelial dystrophies, such as Fuchs' endothelial dystrophy, involve the innermost layer of the cornea and lead to corneal edema.
Question 28: Which of the following statements about Fuchs' corneal dystrophy is incorrect?
- A. Endothelial dystrophy
- B. Occurs in old age
- C. Unilateral condition (Correct Answer)
- D. Posterior dystrophy
Explanation: ***Unilateral condition - INCORRECT STATEMENT*** - **Fuchs' corneal dystrophy** is typically a **bilateral condition**, although it can be asymmetric in its presentation. - The disease often affects both eyes, progressing from early morning blurriness to constant visual impairment. - This is the INCORRECT statement - Fuchs' is NOT unilateral. *Posterior dystrophy - Correct statement* - **Fuchs' corneal dystrophy** is classified as a posterior corneal dystrophy, meaning it primarily affects the **corneal endothelium** and Descemet's membrane. - This posterior involvement leads to the characteristic guttata and corneal edema. *Endothelial dystrophy - Correct statement* - It is fundamentally an **endothelial dystrophy**, resulting from primary dysfunction and loss of corneal endothelial cells. - The compromised endothelial pump function leads to **stromal edema** and reduced visual acuity. *Occurs in old age - Correct statement* - Fuchs' corneal dystrophy typically presents in **middle to old age**, with symptoms often becoming noticeable in individuals over 50. - While congenital forms of corneal dystrophy exist, Fuchs' is not usually one of them.
Question 29: Corneal sensations are decreased in all of the following conditions except:
- A. Neuroparalytic keratitis
- B. Leprosy
- C. Herpetic keratitis
- D. Recurrent corneal erosion syndrome (Correct Answer)
Explanation: ***Recurrent corneal erosion syndrome*** - This condition involves **defective adhesion** of the corneal epithelium to the underlying Bowman's layer and basement membrane, leading to sudden, severe pain upon waking. - While it causes **pain** and **epithelial defects**, it does not primarily involve nerve damage or decreased corneal sensation; rather, episodes are often very painful due to exposed nerve endings. *Herpetic keratitis* - Caused by the **herpes simplex virus (HSV)**, which can infect the trigeminal nerve and lead to **trophic changes** in the cornea. - This viral infection often results in **significant reduction** or loss of corneal sensation, making the eye more vulnerable to trauma and delayed healing. *Neuroparalytic keratitis* - This condition is also known as **neurotrophic keratitis** and results from damage to the **trigeminal nerve**, which supplies sensation to the cornea. - Loss of corneal sensation leads to impaired reflex tearing and blinking, making the cornea susceptible to epithelial breakdown and ulceration due to lack of protective mechanisms. *Leprosy* - In ocular leprosy, the **Mycobacterium leprae** directly invades the ciliary nerves, significantly impairing corneal sensation. - This reduced sensation in leprosy patients increases the risk of **corneal ulcers** and opacification due to undetected foreign bodies and trauma.
Question 30: Normal level of visual acuity is attained at which age
- A. 6 months
- B. 1 year
- C. 3 years
- D. 6 years (Correct Answer)
Explanation: ***6 years*** - **Normal adult visual acuity (20/20 or 6/6)** is typically achieved around the age of **6 years** as the visual system fully matures. - This age allows for the complete development of **foveal vision** and **binocular functions**. *6 months* - At 6 months of age, an infant's visual acuity is still developing and is typically around **20/200 to 20/400**. - While significant visual development occurs by this age, including **face recognition and tracking objects**, it is not yet at adult levels. *1 year* - By one year, visual acuity improves to approximately **20/50 to 20/100**. - Infants at this age are able to **distinguish fine details** and have improved **depth perception**, but full maturity is still some years away. *3 years* - At 3 years of age, visual acuity is generally around **20/30 to 20/40**. - Children at this stage are able to perform **visual tasks** like drawing and recognizing letters, but subtle refinements are still ongoing.