Pediatric Ophthalmology and Strabismus — MCQs
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Which of the following statements about divergent squint is true?
Onset of stereopsis occurs at the age of:
Which muscle paralysis causes right esotropia?
In the context of ophthalmology, what does the acronym BSGT refer to?
A 65-year-old male with a history of hypertension and diabetes presents to the OPD with complaints of diplopia and squint. On examination, the secondary deviation is more than the primary deviation. Which of the following is the most likely diagnosis?
Esotropia is usually associated with:
The most common type of strabismus seen in myopes is?
Strabismic amblyopia is more common in patients with:
Which muscle is primarily affected in Duane syndrome?
Normal level of visual acuity is attained at which age
Pediatric Ophthalmology and Strabismus Indian Medical PG Practice Questions and MCQs
Question 281: Which of the following statements about divergent squint is true?
- A. It is more common in adults than children.
- B. It is also known as exotropia. (Correct Answer)
- C. It is associated with 6th nerve palsy.
- D. It is the most common type of squint in children.
Explanation: ***It is also known as exotropia.*** - **Divergent squint** refers to the outward deviation of one eye, which is medically termed **exotropia**. - This condition is characterized by the eyes turning away from each other. *It is associated with 6th nerve palsy.* - **6th nerve (abducens) palsy** primarily causes **esotropia** (convergent squint), as it impairs the lateral rectus muscle responsible for outward eye movement. - Patients with 6th nerve palsy would have difficulty moving the affected eye outwards, leading to it turning inwards. *It is more common in adults than children.* - **Exotropia** (divergent squint) is actually **more prevalent in children** than in adults, especially the intermittent form. - While it can persist into adulthood, its onset is most commonly observed during childhood. *It is the most common type of squint in children.* - **Exotropia** is common, but **esotropia** (convergent squint) is generally considered the **most common type of squint in children**, particularly accommodative esotropia. - Esotropia involves the inward deviation of one or both eyes.
Question 282: Onset of stereopsis occurs at the age of:
- A. 3 to 5 months (Correct Answer)
- B. 1 to 2 years
- C. 5 years
- D. 7 years
Explanation: ***3 to 5 months*** - **Stereopsis**, or **binocular depth perception**, typically develops between **3 to 5 months of age** as the visual system matures and the brain learns to fuse images from both eyes. - This developmental window is crucial for the establishment of normal **depth perception** and is actively assessed during infant visual screenings. *1 to 2 years* - While visual development continues beyond infancy, the **onset of stereopsis** occurs earlier, in the first few months of life, not between 1 to 2 years. - At 1 to 2 years, children are further refining their **hand-eye coordination** and **visual-motor skills**, building upon established **depth perception**. *5 years* - By **5 years of age**, a child's visual system, including stereopsis, should be fully developed, and any significant deficits in **depth perception** at this stage would indicate a developmental problem. - This age represents a mature stage of visual function, not the **initial onset** of stereopsis. *7 years* - At **7 years of age**, the visual system is considered fully mature, and any significant issues with **stereopsis** would likely indicate a long-standing, uncorrected visual impairment that developed much earlier. - The critical period for the development of stereopsis has long passed by this age.
Question 283: Which muscle paralysis causes right esotropia?
- A. Left medial rectus paralysis
- B. Right medial rectus paralysis
- C. Right lateral rectus paralysis (Correct Answer)
- D. Left lateral rectus paralysis
Explanation: ***Right lateral rectus paralysis*** - **Esotropia** is an inward deviation of the eye. A paralyzed **right lateral rectus muscle** would prevent the right eye from abducting (moving outward), causing it to turn inward. - The **lateral rectus muscle** is responsible for abducting the eye, and its paralysis would result in an unopposed pull by the medial rectus, leading to esotropia. *Left medial rectus paralysis* - Paralysis of the **left medial rectus** would prevent the left eye from adducting (moving inward), resulting in an **exotropia** (outward deviation) of the left eye, not right esotropia. - The **medial rectus muscle** adducts the eye, and if paralyzed, the eye would drift outward. *Right medial rectus paralysis* - Paralysis of the **right medial rectus** would prevent the right eye from adducting, leading to an **exotropia** (outward deviation) of the right eye, not an esotropia. - This muscle is responsible for moving the eye inward, and its dysfunction would cause the eye to deviate outwards. *Left lateral rectus paralysis* - Paralysis of the **left lateral rectus** would cause the left eye to deviate inward (left esotropia), as the eye would be unable to abduct. - This condition affects the left eye, not the right eye as indicated in the question.
Question 284: In the context of ophthalmology, what does the acronym BSGT refer to?
- A. Bagolini striated glasses test (Correct Answer)
- B. Bagolini smooth glasses test
- C. Bagolini shiny glasses test
- D. Bagolini stereoscopic glasses test
Explanation: ***Bagolini striated glasses test*** - The acronym **BSGT** specifically refers to the **Bagolini striated glasses test**, which is a method used in ophthalmology and optometry to evaluate a patient's binocular vision and determine the presence and type of **diplopia** or **suppression**. - This test uses special lenses with fine, parallel striations that cause a point source of light to appear as a streak, helping to assess the patient's **correspondence** and **fusion abilities**. *Bagolini smooth glasses test* - The term **"smooth glasses test"** is not a recognized or standard test in optometry. - The distinctive feature of Bagolini lenses is their **striations**, which are critical for the test's function. *Bagolini shiny glasses test* - The term **"shiny glasses test"** is not a recognized or standard test in optometry. - The appearance of the glasses as **"shiny"** does not convey the functional aspect of the test's striations. *Bagolini stereoscopic glasses test* - While the Bagolini test assesses aspects of binocular vision and can indirectly relate to **stereopsis**, it is not primarily called a **"stereoscopic glasses test."** - **Stereoscopic tests** typically use polarized or red-green anaglyph lenses to directly evaluate depth perception, which is distinct from the primary goal of the Bagolini test.
Question 285: A 65-year-old male with a history of hypertension and diabetes presents to the OPD with complaints of diplopia and squint. On examination, the secondary deviation is more than the primary deviation. Which of the following is the most likely diagnosis?
- A. paralytic squint (Correct Answer)
- B. concomitant strabismus
- C. restrictive strabismus
- D. pseudo strabismus
Explanation: ***Paralytic squint*** The key finding of **secondary deviation being greater than primary deviation** is a classic sign of **paralytic strabismus**. This occurs because the paretic eye (due to neurological deficit) has to work harder to fixate, leading to an exaggerated innervation to the yoked muscle in the healthy eye, causing a larger deviation (Hering's law of equal innervation). The patient's age and history of **hypertension and diabetes** increase the risk of **cranial nerve palsies** (e.g., oculomotor, trochlear, abducens), which are common causes of paralytic squint due to microvascular ischemia. *Concomitant strabismus* In **concomitant strabismus**, the degree of deviation remains constant in all directions of gaze, meaning **primary and secondary deviations are equal**. This contradicts the clinical finding in the patient. Concomitant strabismus often presents in childhood and is typically non-paralytic, with no underlying neurological deficit affecting muscle action. *Restrictive strabismus* **Restrictive strabismus** is characterized by physical limitation of eye movement due to mechanical restriction of an extraocular muscle, often seen in conditions like **thyroid eye disease** or **orbital trauma**. While restrictive strabismus can cause diplopia and reduced eye movement, it typically involves a **limited range of motion** and usually does not present with secondary deviation being greater than primary deviation in the same manner as a paralytic squint. *Pseudo strabismus* **Pseudo strabismus** is an apparent misalignment of the eyes where the eyes are actually straight. This can be due to features like a **wide epicanthal fold** or a **small interpupillary distance**. In pseudo strabismus, there is **no true deviation** on cover-uncover testing, and therefore, the concepts of primary and secondary deviation do not apply, nor would there be actual diplopia.
Question 286: Esotropia is usually associated with:
- A. Nearsightedness
- B. Farsightedness (Correct Answer)
- C. Irregular cornea shape
- D. Age-related vision loss
Explanation: ***Farsightedness*** - **Esotropia**, or convergent strabismus, is often associated with **farsightedness** (hyperopia) because the extra focusing effort required to see clearly at near distances can lead to inward turning of the eyes. - The accommodative effort to overcome hyperopia can cause an **overconvergence** of the eyes, resulting in esotropia. *Nearsightedness* - **Nearsightedness** (myopia) is more commonly associated with **exotropia** (eyes turning outward) or no strabismus. - Myopia generally requires less accommodative effort, which would not typically lead to convergent strabismus. *Irregular cornea shape* - An **irregular cornea shape** is characteristic of **astigmatism**, which causes blurred or distorted vision. - While astigmatism can contribute to visual strain, it is not directly or primarily associated with esotropia. *Age-related vision loss* - **Age-related vision loss** typically refers to conditions like **macular degeneration**, cataracts, or presbyopia. - These conditions affect visual acuity but do not directly cause esotropia, which is a misalignment of the eyes.
Question 287: The most common type of strabismus seen in myopes is?
- A. Intermittent Exotropia (Correct Answer)
- B. Intermittent Esotropia
- C. Esotropia Hypotropia complex
- D. Exotropia Hypotropia complex
Explanation: ***Intermittent Exotropia*** - Myopes often employ less **accommodative effort** for near tasks, leading to reduced **accommodative convergence** and an increased tendency for the eyes to drift outwards. - This outward deviation, or **exotropia**, is frequently intermittent, especially during fatigue or inattention. *Intermittent Esotropia* - **Esotropia** is an inward turn of the eye and is typically associated with **hyperopia** due to excessive accommodative effort leading to increased accommodative convergence. - While it can be intermittent, it is not the most common form of strabismus in myopic individuals. *Esotropia hypotropia complex* - This complex involves both an inward deviation (**esotropia**) and a downward deviation (**hypotropia**). - It is not typically seen in healthy myopes and would suggest other underlying **neurological** or **structural abnormalities**. *Exotropia Hypotropia complex* - While **exotropia** can be common in myopes, the additional presence of **hypotropia** (downward deviation) suggests a more complex strabismic picture. - This combination is not the most frequent strabismus seen in uncomplicated myopia and may indicate **cranial nerve palsies** or **orbital anomalies**.
Question 288: Strabismic amblyopia is more common in patients with:
- A. Constant strabismus (Correct Answer)
- B. Alternating strabismus
- C. Latent strabismus
- D. Intermittent strabismus
Explanation: **Constant Strabismus** - In **constant strabismus**, one eye is always deviated, leading to **continuous suppression** of the image from the deviated eye by the brain. - This consistent suppression prevents proper visual development in the deviated eye, resulting in **amblyopia**. *Alternating strabismus* - In **alternating strabismus**, the deviation switches between the two eyes, allowing each eye to take turns fixing. - This alternation helps maintain relatively good visual acuity in both eyes, making **amblyopia less common** or severe. *Latent strabismus* - **Latent strabismus** (phoria) is a deviation that is only present when binocular fusion is disrupted (e.g., when one eye is covered). - Since fusion is typically maintained in daily vision, there is **no constant suppression** of one eye, and amblyopia is rare. *Intermittent strabismus* - **Intermittent strabismus** involves periods of deviation alternating with periods of straight eye alignment, often varying with fatigue or visual tasks. - While it can lead to amblyopia, it is **less common and severe** than with constant strabismus because there are periods when the visual input from both eyes is utilized.
Question 289: Which muscle is primarily affected in Duane syndrome?
- A. Lateral rectus muscle (Correct Answer)
- B. Superior rectus muscle
- C. Medial rectus muscle
- D. Superior oblique muscle
Explanation: ***Lateral rectus muscle*** - In Duane syndrome, the **lateral rectus muscle** is the primarily affected muscle due to **congenital absence or hypoplasia of the abducens nucleus (CN VI)**. - The lateral rectus receives **aberrant innervation from branches of the oculomotor nerve (CN III)** instead of normal abducens innervation. - This leads to **co-contraction** of both medial and lateral rectus muscles during attempted adduction, causing the characteristic **globe retraction and narrowing of palpebral fissure**. - The hallmark clinical finding is **limited or absent abduction** of the affected eye due to the primary lateral rectus dysfunction. *Medial rectus muscle* - The medial rectus has normal innervation from CN III in Duane syndrome. - While it participates in the co-contraction phenomenon, it is **not the primarily affected muscle**. - The pathology originates in the lateral rectus, not the medial rectus. *Superior rectus muscle* - The superior rectus muscle is responsible for **elevation, adduction, and intorsion** of the eye. - Its dysfunction is not characteristic of Duane syndrome, which primarily affects **horizontal eye movements**. *Superior oblique muscle* - The superior oblique muscle primarily causes **depression, abduction, and intorsion** of the eye. - Duane syndrome's core pathology involves the lateral rectus and horizontal gaze limitations, not superior oblique function.
Question 290: 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.
Practice by Chapter
Amblyopia
Practice Questions
Esotropia
Practice Questions
Exotropia
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Vertical Deviations
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Special Forms of Strabismus
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Nystagmus in Children
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Pediatric Cataract
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Retinopathy of Prematurity
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Pediatric Glaucoma
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Pediatric Neuro-ophthalmology
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Genetic Eye Diseases in Children
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Pediatric Ocular Trauma
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