Pediatric Ophthalmology and Strabismus Practice Questions

Q: When should surgery be performed for congenital cataracts with visual disturbances?

As soon as possible (within 6-10 weeks). ***As soon as possible (within 6-10 weeks)*** - **Early surgical intervention** (within the first few weeks of life) is crucial for congenital cataracts to prevent **irreversible visual deficits**, such as **amblyopia**. - The brain's visual pathways develop rapidly in infancy, and prolonged visual deprivation from cataracts can lead to **permanent impairment**. *After 2 months* - This time frame represents a delay that can increase the risk of **amblyopia** and poorer visual outcomes. - The critical period for visual development is very early in life, making immediate intervention vital. *After 4 months* - A delay of four months significantly increases the likelihood of **dense amblyopia** and **strabismus**, making complete visual rehabilitation much more challenging. - At this age, the potential for achieving good vision post-surgery dramatically decreases due to entrenched abnormal visual processing. *After 1 year* - Performing surgery at one year or later for congenital cataracts is generally considered too late, often resulting in **profound and irreversible amblyopia**. - The visual system will have already established abnormal connections, making significant improvement in visual acuity unlikely.

Q: What is the most common cause of amblyopia?

Refractive errors. ***Refractive errors*** - **Refractive amblyopia**, particularly **anisometropia** (a significant difference in refractive power between the eyes), is the most common cause globally, accounting for approximately 50% of all amblyopia cases. - This imbalance prevents clear retinal images from forming in one eye, leading to its visual underdevelopment. *Strabismus* - **Strabismic amblyopia** is caused by ocular misalignment, where the brain suppresses the image from the misaligned eye to avoid double vision. - While a significant cause (30-40% of cases), it is less common overall than amblyopia due to uncorrected refractive errors. *Deprivation amblyopia* - This is caused by any obstruction of the visual axis, such as **congenital cataracts** or **ptosis**, which physically blocks light from reaching the retina. - Although severe, it is the least common type of amblyopia (<10% of cases). *Cortical visual impairment* - This results from damage to the visual cortex or posterior visual pathways, not from abnormal visual input during the critical period of development. - While it causes visual deficits, it is not classified as amblyopia, which is specifically a developmental disorder of the visual system due to abnormal visual experience.

Q: Child with mild squint. Intrauterine, birth history, developmental history till date all normal. Corneal light reflex normal. All other eye parameters normal except exaggerated epicanthal fold. Diagnosis ?

Pseudostrabismus. ***Pseudostrabismus*** * The presence of **exaggerated epicanthal folds** can create the optical illusion of a child having misaligned eyes, even when the eyes are perfectly straight. * The normal **corneal light reflex** (Hirschberg test) confirms that the eyes are properly aligned, and the perceived "squint" is not a true strabismus. *Exophoria (outward drift)* * This condition involves a **tendency for the eyes to drift outwards**, which would be detected by specific cover/uncover tests. * An outward drift would usually result in an abnormal corneal light reflex, and the exaggerated epicanthal folds would not explain this type of misalignment. *Esophoria (inward drift)* * This is a **tendency for the eyes to drift inwards**, which would also be revealed by tests for phorias and often by an abnormal corneal reflex. * The clinical presentation points away from a true inward deviation, as the corneal reflex is normal. *Accommodative esotropia* * This is a **true inward turning of the eye** (strabismus) that is often linked to uncorrected farsightedness (hyperopia). * It would present with an **abnormal corneal light reflex** and would not be explained solely by epicanthal folds, as it involves actual ocular deviation.

Q: How is the angle of squint measured?

Prism. ***Prism*** - The **angle of squint**, which indicates the deviation of the eyes, is most accurately measured using **prisms** in conjunction with the **prism cover test** or **alternate prism cover test**. - Prisms quantify the degree of ocular deviation in **prism diopters** by neutralizing the misalignment so that the light falls correctly on the fovea. *Gonioscopy* - This technique is used to examine the **anterior chamber angle** of the eye, which is relevant for diagnosing conditions like **glaucoma**. - It does not involve measuring the angle of ocular deviation or misalignment of the eyes. *Retinoscopy* - Retinoscopy is an objective method to determine the **refractive error** of the eye (e.g., myopia, hyperopia, astigmatism). - While it assesses the eye's ability to focus light, it does not directly measure the angle of a squint. *Keratometry* - Keratometry measures the **curvature of the cornea**, primarily used for fitting contact lenses or calculating intraocular lens power for cataract surgery. - It does not assess the alignment of the eyes or the magnitude of a squint.

Q: Which of the following statements about amblyopia is true?

Can be associated with strabismus. ***Can be associated with strabismus*** - **Amblyopia**, or **lazy eye**, is a developmental problem where the brain favors one eye over the other, leading to reduced vision in the weaker eye. - **Strabismus** (misalignment of the eyes) is one of the three major causes of amblyopia because the brain suppresses the image from the misaligned eye to avoid **diplopia** (double vision), leading to the visual pathway of that eye not developing properly. - This statement is unequivocally true and represents a well-established association. *Irreversible loss of vision* - Amblyopia, if detected and treated early during the **critical period of visual development** (typically before age 7-8), is often reversible or significantly improvable. - Treatment involves **patching the stronger eye** or using atropine penalization drops to force the brain to use the weaker eye, promoting its visual development. - While some cases may have persistent deficits if detected late, calling it "irreversible" is incorrect. *Primarily caused by uncorrected refractive error* - While **anisometropia** (significant refractive difference between eyes) and **high bilateral refractive errors** are indeed common causes of amblyopia, the word "primarily" suggests this is the main or dominant cause. - Amblyopia has **three equally important categories of causes**: strabismic, refractive (anisometropic/isoametropic), and deprivation amblyopia. - The relative frequency varies by population and screening methods, making it inaccurate to designate one as the singular "primary" cause. - This statement is partially true but less precise than the strabismus association. *None of the above* - This option is incorrect because the statement "Can be associated with strabismus" is definitively true.

Q: What is the term for a latent deviation of the eyes that can be revealed under certain conditions?

Phoria. ***Phoria*** - A **phoria** is a **latent deviation** of the eyes that is normally corrected by the patient's **fusion mechanisms**. - It becomes manifest only when **fusion is disrupted**, such as when one eye is covered or the patient is fatigued. *Apparent squint* - This term is sometimes used to describe the **optical illusion** of strabismus due to facial features, such as a wide nasal bridge or epicanthal folds, when the eyes are actually aligned. - It is not a true ocular misalignment but rather a perceived deviation. *Manifest strabismus* - **Manifest strabismus**, also known as **tropia**, is a **constant or intermittent deviation** of one or both eyes that is always present and cannot be controlled by the patient's fusion mechanisms. - It is a **visible misalignment** of the eyes under normal viewing conditions. *Tropia* - **Tropia** is synonymous with **manifest strabismus**, meaning the eye deviation is **always present** and visible under binocular viewing conditions. - Unlike phoria, a tropia is not masked by fusion and does not require disruption of fusion to be observed.

Q: Which muscle is most commonly operated on during squint surgery?

Medial rectus (MR). ***MR*** - The **medial rectus (MR)** muscle is the most frequently operated on during squint (strabismus) surgery, especially in cases of **esotropia** (inward turning of the eye). - This is because esotropia is a common form of strabismus, and weakening the medial rectus muscle (recession) helps to correct the inward deviation. *LR* - The **lateral rectus (LR)** muscle is operated on less frequently than the medial rectus, primarily in cases of **exotropia** (outward turning of the eye). - While it can be strengthened (resection) or weakened (recession), esotropia is generally more prevalent, making the MR more commonly targeted. *SR* - The **superior rectus (SR)** muscle primarily elevates the eye and is typically involved in vertical strabismus or cyclovertical deviations. - Surgery on the superior rectus is less common than on the horizontal recti (MR and LR) because horizontal deviations are more prevalent. *SO* - The **superior oblique (SO)** muscle is responsible for intorsion, depression, and abduction of the eye; it is often involved in cyclovertical strabismus. - Surgery on the superior oblique is complex and less frequently performed than on the horizontal recti due to the lower incidence of isolated superior oblique dysfunction requiring surgical correction.

Q: All are true about concomitant squint except which of the following?

There may be a limitation of movement in some cases. ***There may be a limitation of movement in some cases.*** - In concomitant squint, there is **no primary limitation of ocular movement**; the deviation is constant in all directions of gaze. - A limitation of movement would suggest an **incomitant** or paralytic squint, where the deviation varies with gaze direction. *Angle of primary deviation is equal to angle of secondary deviation* - This statement is **true** for concomitant squints, meaning the deviation is the same regardless of which eye is fixing. - Primary deviation refers to the deviation when the unaffected eye is fixing, and secondary deviation is when the affected eye is fixing. *Diplopia is typically absent* - This statement is generally **true** in concomitant strabismus, especially if the condition is long-standing and develops in childhood. - The brain often adapts to avoid double vision through mechanisms like **suppression** or **amblyopia**. *Position of head is typically normal.* - This statement is generally **true** for concomitant squints, as there is no specific gaze direction that minimizes the deviation. - A **compensatory head posture** (e.g., head turn or tilt) is more characteristic of **incomitant strabismus**, where it is adopted to maintain single vision in the field of action of a paretic muscle.

Q: Esotropia is commonly seen in which type of refractive error?

Hypermetropia. ***Hypermetropia*** - **Esotropia**, or convergent strabismus, is commonly associated with **uncorrected hypermetropia**, especially in children. - The constant effort to **accommodate** to see clearly for hypermetropic individuals can lead to excessive convergence, causing the eye to turn inward. *Myopia* - Myopia, or **nearsightedness**, rarely causes esotropia. - In some cases, high myopia can be associated with **exotropia** (divergent strabismus) due to reduced accommodative effort. *Astigmatism* - **Astigmatism** causes blurry vision at all distances due to an irregularly shaped cornea or lens, but it is not directly linked to specific forms of strabismus like esotropia or exotropia. - While it can contribute to **amblyopia** if severe and uncorrected, it does not typically cause the eyes to turn inward. *Presbyopia* - **Presbyopia** is an age-related loss of the eye's ability to focus on nearby objects due to stiffening of the lens. - It affects accommodation but does not cause strabismus such as esotropia; it typically begins around age 40.

Question 1

When should surgery be performed for congenital cataracts with visual disturbances?

Accepted Answer

As soon as possible (within 6-10 weeks)

Answer

After 2 months

Answer

After 4 months

Answer

After 1 year

Question 2

What is the most common cause of amblyopia?

Accepted Answer

Refractive errors

Answer

Cortical visual impairment

Answer

Strabismus

Answer

Deprivation amblyopia

Question 3

Child with mild squint. Intrauterine, birth history, developmental history till date all normal. Corneal light reflex normal. All other eye parameters normal except exaggerated epicanthal fold. Diagnosis ?

Accepted Answer

Pseudostrabismus

Answer

Exophoria (outward drift)

Answer

Esophoria (inward drift)

Answer

Accommodative esotropia

Question 4

How is the angle of squint measured?

Accepted Answer

Prism

Answer

Gonioscopy

Answer

Retinoscopy

Answer

Keratometry

Question 5

Which of the following statements about amblyopia is true?

Accepted Answer

Can be associated with strabismus

Answer

Irreversible loss of vision

Answer

Primarily caused by uncorrected refractive error

Answer

None of the above

Question 6

What is the term for a latent deviation of the eyes that can be revealed under certain conditions?

Accepted Answer

Phoria

Answer

Tropia

Answer

Apparent squint

Answer

Manifest strabismus

Question 7

Which muscle is most commonly operated on during squint surgery?

Accepted Answer

Medial rectus (MR)

Answer

Lateral rectus (LR)

Answer

Superior rectus (SR)

Answer

Superior oblique (SO)

Question 8

All are true about concomitant squint except which of the following?

Accepted Answer

There may be a limitation of movement in some cases

Answer

Angle of primary deviation is equal to angle of secondary deviation

Answer

Diplopia is typically absent

Answer

Position of head is typically normal.

Question 9

Esotropia is commonly seen in which type of refractive error?

Accepted Answer

Hypermetropia

Answer

Myopia

Answer

Astigmatism

Answer

Presbyopia

Question 10

What conditions can be diagnosed using the cover-uncover test?

Accepted Answer

Eye alignment disorders including strabismus and heterophoria

Answer

Convergent strabismus (Esotropia)

Answer

Latent misalignment (Heterophoria)

Answer

Strabismus (Squint)

Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus — MCQs

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