Anatomy
2 questionsWhich of the following extraocular muscle has the longest tendon?
After trauma, a person cannot move their eye outward beyond the midpoint. Which nerve is injured?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 611: Which of the following extraocular muscle has the longest tendon?
- A. Medial rectus
- B. Superior rectus
- C. Superior oblique (Correct Answer)
- D. Inferior oblique
Explanation: ***Superior oblique*** - The superior oblique muscle has the **longest tendon** and overall length of all extraocular muscles because it passes through the **trochlea**, a cartilaginous pulley. - Its long course allows it to have a complex action, primarily **intorsion, depression, and abduction** of the eye [1]. *Superior rectus* - The superior rectus is one of the **straight muscles** (recti) and is not the longest. - Its primary actions are **elevation, adduction, and intorsion** of the eyeball [1]. *Medial rectus* - The medial rectus is another **straight muscle** and is generally considered the **strongest** but not the longest extraocular muscle. - Its main action is **adduction** (moving the eye inward) [1]. *Inferior oblique* - The inferior oblique is the **shortest** of all the extraocular muscles. - Its primary actions are **extorsion, elevation, and abduction** of the eyeball [1].
Question 612: After trauma, a person cannot move their eye outward beyond the midpoint. Which nerve is injured?
- A. 3rd
- B. 4th
- C. 6th (Correct Answer)
- D. 2nd
Explanation: ***6th*** - The **abducens nerve (CN VI)** innervates the **lateral rectus muscle**, which is responsible for moving the eye **outward (abduction)** [1]. - Injury to the abducens nerve would result in an inability to move the eye laterally, causing an **esotropia** (eye turned inward at rest) [1]. *2nd* - The **optic nerve (CN II)** is responsible for **vision**, not eye movement [2]. - Damage to this nerve would cause **visual field defects** or **blindness** [3]. *3rd* - The **oculomotor nerve (CN III)** controls most extraocular muscles, including the **medial, superior, and inferior rectus** and **inferior oblique muscles**, as well as the **levator palpebrae superioris** and **pupillary constriction** [2]. - Injury to CN III would lead to a **down and out deviation of the eye**, **ptosis**, and a **dilated pupil** [2]. *4th* - The **trochlear nerve (CN IV)** innervates the **superior oblique muscle**, which primarily causes **intorsion** (rotation downward and inward) [1]. - Damage to this nerve results in **vertical diplopia**, especially when looking down and in, and a characteristic **head tilt** to compensate [3].
Internal Medicine
1 questionsWhat is the most common cause of ophthalmoplegia in adults?
NEET-PG 2012 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 611: What is the most common cause of ophthalmoplegia in adults?
- A. Cranial nerve palsy (Correct Answer)
- B. Myasthenia gravis
- C. Diabetes mellitus
- D. Trauma
Explanation: ***Cranial nerve palsy*** - **Cranial nerve palsies**, particularly those affecting cranial nerves III, IV, or VI, are the most frequent causes of isolated ophthalmoplegia in adults [1]. - They can result from various etiologies like **ischemia**, **compression**, or **inflammation**, directly impairing the nerves responsible for eye movement [1]. *Myasthenia gravis* - While it frequently causes **ocular symptoms** (ptosis and diplopia), it typically presents with **fluctuating weakness** that worsens with sustained effort [1]. - It's a neuromuscular junction disorder, not a primary cranial nerve issue, and often affects other muscle groups beyond the eyes. *Diabetes mellitus* - **Diabetic ophthalmoplegia** is a specific type of cranial nerve palsy (often CN III or VI) caused by microvascular ischemia. - While common in diabetics, it is a *cause* of cranial nerve palsy, not the overarching most common cause of ophthalmoplegia itself. *Trauma* - **Trauma** can certainly cause ophthalmoplegia, often due to direct damage to **extraocular muscles**, **orbital fractures**, or **cranial nerve injury**. - However, in the general adult population, non-traumatic cranial nerve palsies are more frequently encountered as the cause of ophthalmoplegia.
Ophthalmology
6 questionsWhat is the most common complication of pars planitis?
Jack in box scotoma is seen after correction of Aphakia by?
Shaffer's sign is seen in ?
What is the most common cause of vitreous hemorrhage in diabetic retinopathy?
What is the term for the fusion of the palpebral and bulbar conjunctiva?
Herpetic keratitis is treated by which of the following?
NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 611: What is the most common complication of pars planitis?
- A. Cataract (clouding of the lens) (Correct Answer)
- B. Retinal detachment (separation of retina)
- C. Cystoid macular edema (swelling of central retina)
- D. Glaucoma (increased intraocular pressure)
Explanation: **Cataract (clouding of the lens)** - **Cataract formation** is the most common ocular complication in patients with pars planitis, often due to chronic inflammation or steroid use. - The inflammation can disrupt lens metabolism, leading to **opacification** over time. *Retinal detachment (separation of retina)* - While possible, **retinal detachment** is a less common complication of pars planitis compared to cataract formation. - It can occur in severe cases, often due to vitreous traction on fragile peripheral retina or tears associated with **snowbanking**. *Cystoid macular edema (swelling of central retina)* - **Cystoid macular edema (CME)** is a significant cause of vision loss in pars planitis but is not the most frequent complication overall. - It results from the inflammatory compromise of the blood-retinal barrier, leading to fluid accumulation in the **macula**. *Glaucoma (increased intraocular pressure)* - **Glaucoma** can occur in pars planitis, often secondary to chronic inflammation affecting the **trabecular meshwork** or prolonged steroid use. - However, it is less common than cataracts and CME as a primary complication.
Question 612: Jack in box scotoma is seen after correction of Aphakia by?
- A. IOL
- B. Spectacles (Correct Answer)
- C. Contact lens
- D. None of the options
Explanation: ***Spectacles*** - **Jack-in-the-box scotoma** describes a visual phenomenon where objects appear to jump into and out of the field of vision. This occurs due to the **peripheral scotoma** and **ring scotoma** created by high-plus aphakic spectacle lenses. - Aphakic spectacles cause significant **magnification of the central visual field** (about 25-30%) and a corresponding minification/displacement of the peripheral field, leading to areas where objects are transiently obscured or reappear. *IOL* - An **intraocular lens (IOL)** replaces the natural lens within the eye, providing a much more stable and centered optical correction. - IOLs generally do not cause significant magnification changes or the peripheral scotoma associated with aphakic spectacles. *Contact lens* - **Contact lenses** sit directly on the cornea, offering a visual correction that is much closer to the nodal point of the eye than spectacles. - This placement results in less peripheral distortion and magnification compared to spectacles, making jack-in-the-box scotoma unlikely. *None of the options* - As **aphakic spectacles** are known to cause jack-in-the-box scotoma, this option is incorrect.
Question 613: Shaffer's sign is seen in ?
- A. Acute angle-closure glaucoma
- B. Diabetic retinopathy
- C. Age-related macular degeneration
- D. Retinal detachment (Correct Answer)
Explanation: ***Retinal detachment*** - **Shaffer's sign** refers to the presence of **pigment cells** (tobacco dust) in the **anterior vitreous**, indicating a retinal break or detachment. - This sign is due to the release of retinal pigment epithelium cells into the vitreous following a tear in the retina. *Acute angle-closure glaucoma* - This condition is characterized by a **sudden increase in intraocular pressure** due to blocked fluid outflow, causing pain, redness, and blurred vision. - It does not involve pigment cells in the vitreous, but rather changes in the **anterior chamber angle**. *Diabetic retinopathy* - This is a microvascular complication of diabetes, leading to damage to the blood vessels in the retina, causing **hemorrhages**, **exudates**, and **neovascularization**. - It does not typically present with free pigment in the vitreous as a primary diagnostic sign. *Age-related macular degeneration* - This condition affects the **macula**, often causing distorted vision and central vision loss, and is characterized by drusen and atrophy. - While it can involve retinal changes, it does not classically present with pigment cells in the vitreous as a diagnostic indicator.
Question 614: What is the most common cause of vitreous hemorrhage in diabetic retinopathy?
- A. Non-proliferative diabetic retinopathy
- B. Proliferative diabetic retinopathy (Correct Answer)
- C. Severe non-proliferative diabetic retinopathy
- D. Diabetic macular edema
Explanation: ***Proliferative diabetic retinopathy*** - **Neovascularization** is the hallmark of proliferative diabetic retinopathy (PDR), where new, fragile blood vessels grow on the surface of the retina and optic disc. - These delicate vessels can easily rupture and bleed into the vitreous humor, leading to a **vitreous hemorrhage**. *Non-proliferative diabetic retinopathy* - This stage is characterized by **microaneurysms**, hemorrhages, and cotton wool spots, but typically lacks significant neovascularization. - While it involves retinal vascular damage, the absence of **newly formed, fragile vessels** makes vitreous hemorrhage less common. *Severe non-proliferative diabetic retinopathy* - This stage shows extensive microvascular abnormalities, including numerous hemorrhages and venular beading, but generally **still no new vessel formation**. - Without the presence of **fragile neovascular membranes**, the risk of significant vitreous hemorrhage is lower compared to PDR. *Diabetic macular edema* - This condition involves **fluid leakage** from damaged retinal vessels into the macula, causing vision loss. - While it's a common complication of diabetes, it primarily causes **macular swelling** and does not directly lead to vitreous hemorrhage.
Question 615: What is the term for the fusion of the palpebral and bulbar conjunctiva?
- A. Trichiasis (inward growth of eyelashes)
- B. Ectropion (outward turning of eyelid)
- C. Symblepharon (Correct Answer)
- D. Tylosis (thickening of skin on palms and soles)
Explanation: ***Symblepharon*** - **Symblepharon** is the term for the adhesion between the **palpebral conjunctiva** (lining the eyelid) and the **bulbar conjunctiva** (covering the eyeball). - This condition can limit eye movement and cause chronic irritation, often resulting from severe conjunctival inflammation or injury. *Trichiasis (inward growth of eyelashes)* - **Trichiasis** refers to the misdirection of eyelashes such that they rub against the cornea or conjunctiva. - It causes irritation, foreign body sensation, and can lead to corneal abrasion, but it does not involve fusion of conjunctival layers. *Ectropion (outward turning of eyelid)* - **Ectropion** is a condition where the lower eyelid turns outward or sags away from the eyeball. - This exposes the conjunctiva, causing dryness, irritation, and epiphora (excessive tearing), but it is not a fusion of conjunctival tissues. *Tylosis (thickening of skin on palms and soles)* - **Tylosis** is a medical term referring to diffuse **hyperkeratosis** or thickening of the skin, typically observed on the palms and soles. - This condition is completely unrelated to the conjunctiva or eye structures.
Question 616: Herpetic keratitis is treated by which of the following?
- A. Analgesics
- B. Atropine
- C. Steroids
- D. Acyclovir (Correct Answer)
Explanation: ***Acyclovir*** - **Acyclovir** is an **antiviral agent** that specifically targets the **herpes simplex virus**, which is the causative agent of herpetic keratitis. - It works by inhibiting viral DNA replication, thereby reducing viral load and preventing further damage to the cornea. *Analgesics* - **Analgesics** are used to manage pain but do not address the **viral etiology** of herpetic keratitis. - While they can improve patient comfort, they are not a definitive treatment for the underlying infection. *Atropine* - **Atropine** is a **cycloplegic agent** used to paralyze the ciliary muscle and dilate the pupil, often to reduce pain from ciliary spasms in uveitis. - It does not have **antiviral properties** and is not effective against the herpes virus. *Steroids* - **Corticosteroids** can suppress inflammation but are generally **contraindicated** in active herpetic keratitis, especially in the epithelial form. - They can worsen the viral infection by compromising the immune response, potentially leading to **corneal ulceration** and perforation.
Pediatrics
1 questionsNeonatal conjunctivitis is caused by all of the following except:
NEET-PG 2012 - Pediatrics NEET-PG Practice Questions and MCQs
Question 611: Neonatal conjunctivitis is caused by all of the following except:
- A. Chlamydia
- B. Pseudomonas
- C. Aspergillus (Correct Answer)
- D. Gonococcus
Explanation: ***Aspergillus*** - **Fungal infections** of the eye, particularly by *Aspergillus*, are extremely rare in neonates and typically present as **keratitis** rather than conjunctivitis. - While *Aspergillus* can cause severe infections in immunocompromised individuals, it is not a common cause of neonatal conjunctivitis. *Gonococcus* - **_Neisseria gonorrhoeae_** is a well-known cause of **ophthalmia neonatorum** (gonococcal conjunctivitis), presenting as severe, purulent discharge usually within the first 2-5 days of life. - This infection can lead to **corneal ulceration** and blindness if untreated. *Chlamydia* - **_Chlamydia trachomatis_** is the most common bacterial cause of **neonatal conjunctivitis**, typically appearing 5-14 days after birth. - It causes a **mucopurulent discharge** and can be associated with **chlamydial pneumonia** in infants. *Pseudomonas* - **_Pseudomonas aeruginosa_** can cause severe and rapidly progressive **neonatal conjunctivitis** and **keratitis**, especially in premature infants or those exposed to contaminated solutions. - It is a highly aggressive pathogen that can lead to significant ocular morbidity.