Pediatric Ophthalmology and Strabismus Practice Questions

Q: Refractive error most commonly concerned with divergent strabismus is:

Myopia. ### Explanation **1. Why Myopia is Correct:** The association between refractive errors and strabismus is primarily driven by the **AC/A ratio (Accommodative Convergence to Accommodation ratio)**. In **Myopia** (nearsightedness), the patient has a clear near point and does not need to accommodate to see objects up close. Since accommodation and convergence are neurologically linked, a lack of accommodative effort leads to **decreased accommodative convergence**. This lack of inward pulling force allows the eyes to drift outward, resulting in **Divergent Strabismus (Exotropia)**. **2. Why Other Options are Incorrect:** * **Hypermetropia:** This is most commonly associated with **Convergent Strabismus (Esotropia)**. Hypermetropes must accommodate excessively to clear their vision; this over-accommodation triggers excessive accommodative convergence, pulling the eyes inward (Accommodative Esotropia). * **Astigmatism:** While uncorrected astigmatism can cause blurred vision and potentially lead to sensory strabismus, it does not have a specific, direct physiological link to divergence like myopia does. * **Presbyopia:** This is an age-related loss of accommodation in adults. While it affects the near point, it is not a primary cause of childhood strabismus. **3. High-Yield Clinical Pearls for NEET-PG:** * **Donders' Theory:** States that hypermetropia leads to esotropia and myopia leads to exotropia. * **Accommodative Esotropia:** Usually seen with hypermetropia of +2.00 to +7.00 D. * **Sensory Exotropia:** Occurs when one eye has poor vision (e.g., dense cataract or optic atrophy) in an adult or older child, leading to an outward drift. * **Management Tip:** The first step in treating accommodative strabismus is always the full correction of the refractive error with spectacles.

Q: Which of the following ophthalmological anomalies is seen in WAGR syndrome?

Aniridia. **Explanation:** **WAGR Syndrome** is a rare genetic contiguous gene deletion syndrome caused by the microdeletion of chromosome **11p13**. The acronym stands for **W**ilms tumor, **A**niridia, **G**enitourinary anomalies, and mental **R**etardation. **Why Aniridia is the correct answer:** The deletion involves the **PAX6 gene**, which is the "master control gene" for eye development. A mutation or deletion of PAX6 leads to **Aniridia** (partial or complete absence of the iris). In WAGR syndrome, aniridia is often the first clinical sign noted at birth and serves as a critical marker for the potential development of Wilms tumor (nephroblastoma). **Analysis of Incorrect Options:** * **Lens coloboma:** While colobomas are congenital anomalies, they are typically associated with the *CHARGE* syndrome or isolated genetic defects, not specifically the 11p13 deletion. * **Retinitis pigmentosa:** This is a hereditary retinal dystrophy involving photoreceptors. It is not a component of the WAGR complex. * **Trabeculodysgenesis:** This is the underlying structural defect in *Primary Congenital Glaucoma*. While patients with aniridia can develop secondary glaucoma (due to synechial closure of the angle), trabeculodysgenesis is not the defining feature of WAGR. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Microdeletion of **11p13** affecting **WT1** (Wilms tumor) and **PAX6** (Aniridia) genes. * **Monitoring:** Children with isolated aniridia must be screened with serial abdominal ultrasounds every 3 months until age 7 to detect Wilms tumor early. * **Ocular Complications of Aniridia:** Glaucoma (most common), foveal hypoplasia (leading to nystagmus and poor vision), and limbal stem cell deficiency. * **Gillespie Syndrome:** A variant featuring aniridia, cerebellar ataxia, and mental retardation (distinct from WAGR).

Q: All of the following may be present in Duane's retraction syndrome except?

Narrowing of palpebral fissure in abduction. **Explanation:** Duane’s Retraction Syndrome (DRS) is a congenital cranial dysinnervation disorder caused by the absence or hypoplasia of the **abducens (VI) nerve** nucleus, with paradoxical innervation of the lateral rectus by the **oculomotor (III) nerve**. **Why Option C is the correct answer:** In DRS, the hallmark feature is the **narrowing of the palpebral fissure on adduction**, not abduction. This occurs because, during adduction, both the medial and lateral recti receive nerve impulses simultaneously (co-contraction). This "tug-of-war" effect pulls the globe into the orbit (enophthalmos), causing the eyelids to close slightly. Conversely, on abduction, the palpebral fissure typically widens. **Analysis of Incorrect Options:** * **Option A (Suppression):** Since DRS is usually congenital and unilateral, children develop suppression of the affected eye to avoid diplopia. Amblyopia may also occur. * **Option B (Head turn):** Patients often adopt a compensatory face turn toward the side of the affected eye to maintain binocular single vision and minimize the deviation. * **Option D (Limitation of abduction):** This is a primary feature of DRS (especially Type 1, the most common type), resulting from the lack of innervation by the VI nerve to the lateral rectus. **High-Yield Clinical Pearls for NEET-PG:** * **Huber’s Classification:** * **Type 1:** Limited Abduction (Most common). * **Type 2:** Limited Adduction. * **Type 3:** Limited both Abduction and Adduction. * **Associated Findings:** "Upshoot" or "downshoot" of the eye during adduction. * **Epidemiology:** More common in females and usually affects the **left eye**. * **Systemic Association:** Often associated with **Goldenhar Syndrome**.

Q: What is the most common cause of leukocoria in a newborn?

Congenital cataract. **Explanation:** **Leukocoria**, or a "white pupillary reflex," is a critical clinical sign in pediatric ophthalmology. While several conditions can cause this, **Congenital Cataract** is statistically the **most common cause** of leukocoria in newborns. It involves an opacification of the crystalline lens present at birth, which obstructs the normal red reflex. Early diagnosis is vital to prevent irreversible amblyopia. **Analysis of Options:** * **A. Congenital Cataract (Correct):** It is the leading cause of preventable blindness in children and the most frequent cause of a white reflex in the neonatal period. * **B. Toxocara infection:** This typically presents in older children (preschool/school age) who have contact with puppies or soil. It causes a posterior pole granuloma but is rarely seen in newborns. * **C. Retinoblastoma:** This is the **most common primary intraocular malignancy** in children and the most common *life-threatening* cause of leukocoria. However, it usually presents between 12–18 months of age, not typically at birth. * **D. CMV infection:** While CMV is a common congenital infection, it typically manifests as chorioretinitis rather than a dense white pupillary reflex. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of leukocoria overall:** Congenital Cataract. * **Most common life-threatening cause of leukocoria:** Retinoblastoma. * **Differential Diagnosis (DDx) of Leukocoria:** Remember the mnemonic **"C-R-P"** (Cataract, Retinoblastoma, PHPV/PFV). * **Coats’ Disease:** A common cause of unilateral leukocoria in young males due to telangiectatic retinal vessels and exudation. * **Management:** Congenital cataracts that are visually significant (central, >3mm) should ideally be operated on within the first 4–6 weeks of life to ensure proper visual development.

Q: Exotropia occurs due to which of the following?

Third nerve palsy. **Explanation:** **1. Why Third Nerve Palsy is Correct:** The Oculomotor (3rd) nerve innervates four of the six extraocular muscles: the Medial Rectus (MR), Superior Rectus, Inferior Rectus, and Inferior Oblique. The MR is the primary muscle responsible for **adduction** (turning the eye inward). In a 3rd nerve palsy, the MR is paralyzed, leaving the **Lateral Rectus** (innervated by the 6th nerve) unopposed. This results in the eye being pulled outward, leading to **Exotropia** (divergent squint). Clinically, this presents as a "down and out" eye position due to the unopposed action of the Lateral Rectus and Superior Oblique. **2. Why the Other Options are Incorrect:** * **Optic Neuritis:** This is an inflammatory condition of the optic nerve (CN II). It affects vision and pupillary light reflex (RAPD) but does not directly cause ocular deviation or squint. * **Abducens (6th) Nerve Palsy:** The 6th nerve innervates the Lateral Rectus. Paralysis of this muscle leads to unopposed action of the Medial Rectus, resulting in **Esotropia** (convergent squint), not exotropia. * **Papilloedema:** This refers to bilateral optic disc swelling due to increased intracranial pressure. While it may cause a secondary 6th nerve palsy (false localizing sign) leading to esotropia, it does not inherently cause exotropia. **NEET-PG High-Yield Pearls:** * **3rd Nerve Palsy Triad:** Ptosis, "Down and Out" eye, and Mydriasis (if parasympathetic fibers are involved). * **Rule of Pupil:** Pupil involvement suggests compressive lesions (e.g., PCom artery aneurysm); pupil sparing suggests ischemic causes (e.g., Diabetes). * **Primary Divergent Squint:** Most commonly seen as Intermittent Exotropia (X(T)) in children.

Q: The following light reflex is seen in a patient. How much is the deviation?

45 PD. ***45 PD*** - The image displays the **Hirschberg test** (corneal light reflex test), which estimates the angle of strabismus. The light reflex is displaced nasally in the left eye, indicating an outward deviation (**exotropia**). - A reflex located approximately midway between the pupil margin and the limbus corresponds to a deviation of about 22.5 degrees, which is equivalent to **45 prism diopters (PD)**. *30 PD* - A deviation of 30 PD corresponds to approximately 15 degrees, where the light reflex would be seen at the **pupillary margin**. - This represents a smaller deviation than what is depicted in the image. *90 PD* - This value corresponds to a large deviation of 45 degrees, where the light reflex would be located at the **limbus** (the junction of the cornea and sclera). - The light reflex in the image is positioned midway between the pupil and limbus, indicating a smaller deviation than what would be seen with a full 90 PD deviation. *90°* - This is an extremely large deviation and is also an incorrect unit of measurement for this test; **prism diopters (PD)** are the standard unit used to quantify strabismus. - One degree of deviation is roughly equal to two prism diopters, making a 90-degree deviation (180 PD) anatomically inconsistent with the image.

Q: The cover-uncover test is performed to diagnose various eye conditions. Which of the following is not detected by this test?

Amblyopia. ***Amblyopia*** - Amblyopia, often called a "lazy eye," is a neurodevelopmental disorder characterized by reduced **visual acuity** in one eye, which is not correctable by refractive means alone. - It is diagnosed by assessing vision with tools like a **Snellen chart**, whereas the cover-uncover test is designed to evaluate **ocular alignment** and motor fusion, not sensory function like visual acuity. *Latent Squint* - A latent squint, or **heterophoria**, is a tendency for the eyes to misalign when binocular vision is interrupted, such as when one eye is covered. - The **uncover** portion of the test reveals a phoria, as the eye that was covered will move to re-establish fixation once the occluder is removed. *Manifest Squint* - A manifest squint, or **heterotropia**, is a constant, observable misalignment of one eye. - The **cover test** component identifies a tropia by observing the movement of the uncovered eye; if it moves to take up fixation when the other eye is covered, a manifest squint is present. *Lateral Nystagmus* - **Nystagmus** is an involuntary, rhythmic movement of the eyes. Certain types, like latent nystagmus, become apparent or worsen when one eye is occluded. - The cover-uncover test, by breaking binocular fusion, can elicit or accentuate **latent nystagmus**, making it observable to the examiner.

Question 1

Refractive error most commonly concerned with divergent strabismus is:

Accepted Answer

Myopia

Answer

Astigmatism

Answer

Hypermetropia

Answer

Presbyopia

Question 2

Which of the following ophthalmological anomalies is seen in WAGR syndrome?

Accepted Answer

Aniridia

Answer

Lens coloboma

Answer

Retinitis pigmentosa

Answer

Trabeculodysgenesis

Question 3

All of the following may be present in Duane's retraction syndrome except?

Accepted Answer

Narrowing of palpebral fissure in abduction

Answer

Suppression

Answer

Head turn

Answer

Limitation of abduction

Question 4

What is the test used to assess visual acuity in an infant less than one year of age?

Accepted Answer

Electroretinography

Answer

Electrooculography

Answer

Snellen's chart

Answer

Optical Coherence Tomography

Question 5

What is the most common cause of leukocoria in a newborn?

Accepted Answer

Congenital cataract

Answer

Toxocara infection

Answer

Retinoblastoma

Answer

CMV infection

Question 6

Exotropia occurs due to which of the following?

Accepted Answer

Third nerve palsy

Answer

Optic neuritis

Answer

Abducens nerve palsy

Answer

Papilloedema

Question 7

An 'A' pattern squint is typically associated with weakness or overaction of which extraocular muscle?

Accepted Answer

Superior oblique

Answer

Superior rectus

Answer

Inferior rectus

Answer

Inferior oblique

Question 8

Diplopia is not a presenting feature in which of the following conditions?

Accepted Answer

Latent squint

Answer

Manifest squint

Answer

Paralytic squint

Answer

Anisometropia

Question 9

The following light reflex is seen in a patient. How much is the deviation?

Accepted Answer

45 PD

Answer

90 PD

Answer

30 PD

Answer

90°

Question 10

The cover-uncover test is performed to diagnose various eye conditions. Which of the following is not detected by this test?

Accepted Answer

Amblyopia

Answer

Lateral Nystagmus

Answer

Manifest Squint

Answer

Latent Squint

Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus — MCQs

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