Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus Indian Medical PG Practice Questions and MCQs

Question 271: Obstacles in concomitant squint are:

A. Sensory obstacles
B. Motor obstacles
C. Central obstacles
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - **Concomitant squint** involves **sensory obstacles** (e.g., amblyopia, eccentric fixation), **motor obstacles** (e.g., muscle imbalance, inadequate fusional vergence), and **central obstacles** (e.g., defective brain processing of visual information). - All these factors interact to cause and maintain the misalignment of the eyes. *Sensory obstacles* - These include conditions like **amblyopia** (lazy eye) due to suppression of the deviated eye's image, and **eccentric fixation**, where the fovea is not used for central vision. - While significant, sensory obstacles alone do not fully explain concomitant squint, as motor and central components are also crucial. *Motor obstacles* - These involve issues with the **extraocular muscles**, such as imbalance in muscle tone, or problems with the **neural control** of eye movements, leading to a deviation that is relatively constant in all gaze positions. - Motor obstacles are a key component but are often influenced by central and sensory factors. *Central obstacles* - These refer to problems within the brain's visual pathways and centers responsible for **fusion**, **vergence**, and maintaining **ocular alignment**. - Defective processing of visual input or an inability to maintain binocular vision can directly contribute to squint, highlighting the brain's role in coordinating eye movements.

Question 272: A patient presents with convergent squint in one eye. Vision in the squinting eye is 6/60, and vision in the non-squinting eye is also 6/60. What is the most appropriate next step in management?

A. Glasses
B. Refraction and treat underlying cause of poor vision (Correct Answer)
C. Squint surgery
D. Botulinum toxin

Explanation: ***Refraction and treat underlying cause of poor vision*** - When **both eyes have equally poor vision (6/60)** with a convergent squint, this suggests a **bilateral pathology** affecting visual acuity, not simply a refractive accommodative esotropia. - The **first step** is comprehensive **cycloplegic refraction** to determine if refractive error contributes to the poor vision. - **Equally important** is identifying the **underlying cause** of bilateral vision loss (6/60 in both eyes), which could be: - **Bilateral amblyopia** (though unusual to have equal severity) - **Uncorrected high refractive error** (hypermetropia causing accommodative esotropia) - **Cataracts** (congenital or developmental) - **Retinal pathology** or **optic nerve disorders** - Only after identifying and treating the underlying cause can definitive management of the squint be planned. *Glasses* - While **glasses** may be part of the treatment if refractive error is found, **prescribing glasses alone** without first performing refraction and investigating why both eyes have 6/60 vision is incomplete management. - This option is too narrow and doesn't address the need to identify the underlying pathology causing bilateral poor vision. *Squint surgery* - **Squint surgery** addresses ocular misalignment but does **not improve vision**. - Surgery should only be considered **after** refractive correction, treatment of amblyopia (if present), and management of any underlying pathology. - Operating without addressing the cause of poor vision would be premature. *Botulinum toxin* - **Botulinum toxin** is used for certain types of strabismus as a temporary or alternative to surgery. - Like surgery, it addresses alignment but **not visual acuity**. - The priority is to improve vision and identify the underlying cause before considering alignment procedures.

Question 273: The normal growth of the human eye includes all except

A. Dramatic decrease in lens power in first one year
B. A 4 mm increase in axial length in first 6 months of life
C. An increase in corneal power in first 6 months (Correct Answer)
D. A corneal diameter of 10.5 mm at birth, 12mm by age 2

Explanation: ***An increase in corneal power in first 6 months*** - Normal physiological development of the human eye involves a **decrease in corneal power** during the first 6 months of life. This emmetropization process helps the eye achieve a clearer focus as it grows. - An increase in corneal power would typically lead to **myopic shifts** or other refractive errors if not compensated by other ocular changes. *Dramatic decrease in lens power in first one year* - The human lens is highly positive at birth (around +34.50 D) and undergoes a significant physiological decrease in power during the **first year of life** as part of the emmetropization process. - This reduction in lens power, coupled with the increase in axial length, helps the eye achieve **emmetropia** (normal refractive state). *A 4 mm increase in axial length in first 6 months of life* - The eye undergoes rapid growth after birth, with the axial length increasing significantly, particularly in the **first 6 months of life**. - A 4 mm increase in axial length during this period is an expected part of **normal ocular development** contributing to emmetropization. *A corneal diameter of 10.5 mm at birth, 12mm by age 2* - The average corneal diameter at birth is approximately **9.0 mm to 10.5 mm**, rapidly increasing to about 11.5 mm by age 1 and reaching its adult size of around **12 mm by age 2** to 3 years. - This growth in corneal diameter is a normal part of ocular development and contributes to the overall enlargement of the eye globe.

Question 274: Which test helps to differentiate between concomitant squint and paralytic squint:

A. Cover - uncover test
B. Direct cover test
C. Alternate cover test (Correct Answer)
D. None of the options

Explanation: ***Alternate cover test*** - The **alternate cover test performed in different gaze positions** is the key test to differentiate between concomitant and paralytic squint - In **concomitant squint**: The angle of deviation measured remains **equal in all directions of gaze** - In **paralytic squint**: The angle of deviation **varies in different gaze positions**, being **maximum in the direction of action of the paralyzed muscle** (secondary deviation > primary deviation) - This test, combined with measurement of deviation in nine cardinal positions of gaze, is the **standard clinical method** for this differentiation *Cover-uncover test* - This test is primarily used to detect a **phoria (latent ocular deviation)** - It identifies whether the deviation is latent or manifest - Does not measure deviation in different gaze positions to differentiate types *Direct cover test* - This test identifies a **tropia (manifest ocular deviation)** - Confirms the presence of manifest squint - Does not provide information about variation of deviation in different gazes **Key Principle:** The hallmark difference is that concomitant squint shows **equal deviation in all gazes** while paralytic squint shows **variable deviation** (greatest in the field of action of paralyzed muscle). The alternate cover test with prism measurement in different gaze positions demonstrates this difference.

Question 275: In a child presenting unilateral watering and photophobia which of the following is the least likely disorder?

A. Congenital entropion
B. Congenital glaucoma
C. Congenital NLDO (Correct Answer)
D. Congenital dacryocystitis

Explanation: **Congenital NLDO** - **Congenital nasolacrimal duct obstruction (NLDO)** typically presents with **unilateral watering** (epiphora) due to blockage of tear drainage. - While it causes watering, **photophobia** is not a characteristic symptom of isolated NLDO, making it less likely given the combined presentation. *Congenital entropion* - **Congenital entropion** involves the inward turning of the eyelid margin, causing eyelashes to rub against the cornea. - This irritation can lead to **unilateral watering** and **photophobia** due to corneal abrasion and discomfort. *Congenital glaucoma* - **Congenital glaucoma** is characterized by elevated intraocular pressure, which can cause corneal edema and stretching. - These changes commonly result in **unilateral watering** (epiphora) and marked **photophobia**, often accompanied by **buphthalmos** (enlarged eye). *Congenital dacryocystitis* - **Congenital dacryocystitis** is an infection of the lacrimal sac, often secondary to NLDO. - It presents with **unilateral watering**, discharge, and inflammation of the lacrimal sac, and the associated irritation can induce **photophobia**.

Question 276: A 10-year-old girl presents with a history of poor vision in her right eye. Examination reveals esotropia and amblyopia. What is the most appropriate initial treatment?

A. Strabismus surgery
B. Patching the good eye
C. Corrective glasses (Correct Answer)
D. Atropine drops in the good eye

Explanation: ***Corrective glasses*** - Corrective glasses are the **first-line treatment** for **refractive amblyopia**, by providing a clear retinal image which is crucial for visual development. - In cases of **esotropia**, glasses can correct significant refractive errors, particularly **hyperopia**, which can reduce the accommodative effort leading to **strabismus**. *Patching the good eye* - **Patching** is used to treat **amblyopia** by forcing the brain to use the weaker eye, thereby strengthening its visual pathways. - While effective for amblyopia, it is typically implemented **after** any significant refractive errors have been corrected with glasses. *Strabismus surgery* - **Strabismus surgery** aims to realign the eyes and is usually considered when conservative measures like glasses and patching have not fully corrected the eye deviation. - It is typically performed **after** amblyopia treatment has been initiated or completed, as visual acuity needs to be optimized first. *Atropine drops in the good eye* - **Atropine eye drops** in the good eye blur its vision, similarly forcing the child to use the weaker, amblyopic eye. - This is an alternative to patching, often used in children who may not tolerate patching well, but it's effective **after** refractive correction has been addressed.

Question 277: What is the most appropriate primary surgical option for managing long-standing superior oblique palsy with compensatory head tilt?

A. Superior oblique tuck
B. Inferior oblique weakening (Correct Answer)
C. Medial rectus recession
D. Lateral rectus resection

Explanation: ***Correct: Inferior oblique weakening*** - **Inferior oblique weakening** is the **most common primary surgical procedure** for managing long-standing superior oblique palsy with compensatory head tilt. - In superior oblique palsy, the ipsilateral inferior oblique muscle develops **secondary overaction** in approximately 90% of cases, which is the primary cause of the vertical deviation. - Weakening procedures (such as **inferior oblique recession** or **myectomy**) effectively correct the **hypertropia in adduction**, reduce **torsional deviation**, and improve the **compensatory head tilt**. - This approach addresses the functional problem and is the **first-line surgical intervention** recommended in standard ophthalmology practice. *Incorrect: Superior oblique tuck* - Superior oblique tuck is a **strengthening procedure** for the paretic superior oblique muscle. - This is a technically challenging procedure with **less predictable outcomes** and higher complication rates. - It is typically reserved as a **secondary procedure** when inferior oblique weakening alone is insufficient, or in rare cases with minimal inferior oblique overaction. - Not the standard primary surgical approach for long-standing superior oblique palsy. *Incorrect: Medial rectus recession* - **Medial rectus recession** is used to correct **esotropia** (inward eye deviation). - This procedure does not address the **vertical deviation** or **torsional component** characteristic of superior oblique palsy. - Not indicated for primary management of this condition. *Incorrect: Lateral rectus resection* - **Lateral rectus resection** strengthens the lateral rectus muscle to correct **esotropia** or improve abduction. - Does not affect **vertical eye movements** or **torsion** seen in superior oblique palsy. - Not relevant to the management of this condition.

Question 278: Which of the following is a characteristic feature of paralytic squint?

A. Constant angle of deviation
B. Variable angle of deviation (Correct Answer)
C. No diplopia
D. Normal ocular movements

Explanation: ***Correct: Variable angle of deviation*** - In paralytic squint, the **angle of deviation** changes depending on the direction of gaze and which eye is fixing. It is greatest when the patient attempts to move the eyes in the direction of action of the paretic muscle. - This variability is due to the **paresis** of one or more extraocular muscles, preventing coordinated movement. - This is the **hallmark feature** that distinguishes paralytic from concomitant squint. *Incorrect: Constant angle of deviation* - A **constant angle** of deviation is characteristic of **concomitant squint** (non-paralytic), where the deviation remains the same in all directions of gaze. - In concomitant squint, there is no paralysis of extraocular muscles; rather, it is a problem with **binocular fusion** or control. *Incorrect: No diplopia* - **Diplopia** (double vision) is a common and often prominent symptom in **paralytic squint**, especially when looking in the direction of the paralyzed muscle. - Absence of diplopia is more characteristic of long-standing concomitant squints where **suppression** of the image from the deviating eye has occurred. *Incorrect: Normal ocular movements* - **Paralytic squint** is, by definition, caused by a paresis or paralysis of one or more extraocular muscles, leading to **restricted ocular movements** in the direction of action of the affected muscle. - **Normal ocular movements** would rule out a paralytic squint and suggest either a concomitant squint or no squint at all.

Question 279: Esotropia is common in

A. Farsightedness (Correct Answer)
B. Nearsightedness
C. Normal vision
D. Distorted vision

Explanation: ***Farsightedness*** - **Esotropia**, or an inward turning of the eye, is common in **farsightedness (hyperopia)** because the eyes constantly accommodate to try and focus distant images, which can lead to excessive convergence. - This persistent accommodative effort can overwhelm the **fusional divergence mechanism**, resulting in the eye turning inward. *Nearsightedness* - **Nearsightedness (myopia)** is more commonly associated with **exotropia** (outward turning of the eye), especially in cases of high myopia. - Myopic individuals do not need to accommodate to see distant objects, reducing the stimulus for convergence that might lead to esotropia. *Normal vision* - Individuals with **normal vision (emmetropia)** typically have well-balanced eye alignment and do not experience a predisposition to esotropia due to refractive error. - Other underlying causes for esotropia would need to be considered if it occurs in a person with normal vision. *Distorted vision* - **Distorted vision** (e.g., due to astigmatism or retinal pathology) can contribute to amblyopia or poor vision, but it does not directly lead to esotropia in the same mechanism as uncorrected hyperopia. - While it can be associated with strabismus, it is not the most common direct cause of esotropia compared to refractive errors.

Question 280: 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.

Practice by Chapter

Amblyopia

Practice Questions

Esotropia

Practice Questions

Exotropia

Practice Questions

Vertical Deviations

Practice Questions

Special Forms of Strabismus

Practice Questions

Nystagmus in Children

Practice Questions

Pediatric Cataract

Practice Questions

Retinopathy of Prematurity

Practice Questions

Pediatric Glaucoma

Practice Questions

Pediatric Neuro-ophthalmology

Practice Questions

Genetic Eye Diseases in Children

Practice Questions

Pediatric Ocular Trauma

Practice Questions

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