Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus Indian Medical PG Practice Questions and MCQs

Question 251: Which of the following ophthalmological anomalies is seen in WAGR syndrome?

A. Lens coloboma
B. Retinitis pigmentosa
C. Aniridia (Correct Answer)
D. Trabeculodysgenesis

Explanation: **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).

Question 252: All of the following may be present in Duane's retraction syndrome except?

A. Suppression
B. Head turn
C. Narrowing of palpebral fissure in abduction (Correct Answer)
D. Limitation of abduction

Explanation: **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**.

Question 253: What is the test used to assess visual acuity in an infant less than one year of age?

A. Electroretinography (Correct Answer)
B. Electrooculography
C. Snellen's chart
D. Optical Coherence Tomography

Explanation: **Explanation:** In infants under one year of age, visual acuity cannot be measured using subjective methods like letter charts because the patient is pre-verbal and unable to follow complex instructions. Therefore, **objective electrophysiological tests** are employed. **Why Electroretinography (ERG) is the correct answer:** While ERG primarily measures the electrical response of the retinal photoreceptors and inner layers to light stimulation, it is a vital objective tool used in infants to assess the functional integrity of the retina. In the context of this question's options, it represents the objective assessment of the visual pathway. For more specific acuity, **Visual Evoked Potential (VEP)** or **Preferential Looking Tests (e.g., Teller Acuity Cards)** are also used clinically, but among the provided choices, ERG is the standard objective functional test. **Analysis of Incorrect Options:** * **B. Electrooculography (EOG):** This measures the resting potential between the cornea and Bruch’s membrane (assessing the Retinal Pigment Epithelium). It requires the patient to perform specific side-to-side eye movements, making it impossible to perform accurately in an infant. * **C. Snellen’s Chart:** This is a subjective test requiring literacy and verbal communication. It is typically used for children aged 6 years and older. * **D. Optical Coherence Tomography (OCT):** This is an imaging modality used to view the cross-sectional anatomy of the retina. It measures structure, not functional visual acuity. **High-Yield Clinical Pearls for NEET-PG:** * **Milestone:** A full-term infant should be able to "fix and follow" a target by **3 months** of age. * **Catford Drum:** Used for objective visual acuity based on optokinetic nystagmus. * **Sheridan Gardiner Test:** The most common subjective test for children aged 3–5 years (uses matching letters). * **VEP (Visual Evoked Potential):** The most sensitive objective method to determine visual acuity in non-verbal children.

Question 254: What is the most common cause of leukocoria in a newborn?

A. Congenital cataract (Correct Answer)
B. Toxocara infection
C. Retinoblastoma
D. CMV infection

Explanation: **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.

Question 255: What is the primary treatment for metastatic disease in retinoblastoma?

A. Chemotherapy (Correct Answer)
B. Enucleation
C. Radiotherapy
D. Cryotherapy

Explanation: **Explanation:** **Retinoblastoma** is the most common intraocular malignancy in children. When the disease remains intraocular, the goal is to save the eye and vision. However, once it becomes **metastatic** (spreading to the bone marrow, lymph nodes, or CNS), the condition is systemic and life-threatening. 1. **Why Chemotherapy is Correct:** Metastatic retinoblastoma requires a **systemic approach** to eliminate circulating malignant cells throughout the body. High-dose systemic chemotherapy (often followed by autologous stem cell rescue) is the mainstay of treatment. It is the only modality capable of addressing multi-organ involvement and crossing the blood-brain barrier (in specific protocols) to treat micrometastases. 2. **Why Other Options are Incorrect:** * **Enucleation:** This is a local surgical treatment. While it is the treatment of choice for advanced intraocular tumors (Group E) to prevent spread, it cannot treat disease that has already metastasized. * **Radiotherapy:** External Beam Radiotherapy (EBRT) is a local/regional treatment. While used for orbital recurrence or CNS involvement, it is not the primary treatment for generalized metastatic disease due to the risk of secondary malignancies (especially in patients with the *RB1* germline mutation). * **Cryotherapy:** This is a focal "cold" therapy used only for small, anteriorly located intraocular tumors (less than 3mm in diameter and 2mm in thickness). **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of metastasis:** Direct extension via the **optic nerve** to the CNS. * **Most common distant metastasis:** Bone marrow and skeleton. * **Chemoreduction:** The use of chemotherapy (Vincristine, Etoposide, Carboplatin) to shrink an intraocular tumor to make it amenable to local therapies (like laser or cryo). * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pineal gland tumor (pineoblastoma).

Question 256: Exotropia occurs due to which of the following?

A. Third nerve palsy (Correct Answer)
B. Optic neuritis
C. Abducens nerve palsy
D. Papilloedema

Explanation: **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.

Question 257: According to WHO, which method is applied for prophylactic use in ophthalmia neonatorum?

A. Silver nitrate solution (Correct Answer)
B. Erythromycin ointment
C. Tetracycline ointment
D. Penicillin injection

Explanation: **Explanation:** **Ophthalmia Neonatorum** is a form of conjunctivitis occurring within the first 30 days of life, typically contracted during passage through the birth canal. **1. Why Silver Nitrate is Correct:** The use of **1% Silver Nitrate solution** is known as **Credé’s Prophylaxis**. Historically, it was the first widely adopted method to prevent gonococcal ophthalmia neonatorum. While many developed countries have switched to antibiotic ointments due to the risk of chemical conjunctivitis, the **WHO** continues to recommend 1% Silver Nitrate (or 1% Tetracycline/0.5% Erythromycin) as a cost-effective and accessible prophylactic agent in many settings to prevent *Neisseria gonorrhoeae* infection, which can lead to corneal perforation and blindness. **2. Analysis of Incorrect Options:** * **B & C (Erythromycin/Tetracycline):** While these are the preferred prophylactic agents in the US (CDC guidelines) because they are less irritating than silver nitrate and provide some coverage against *Chlamydia*, the question specifically asks for the classic WHO-recommended prophylactic method often associated with Credé’s method in standard textbooks. * **D (Penicillin injection):** Systemic penicillin is used for the **treatment** of confirmed gonococcal conjunctivitis, not as a routine prophylactic topical measure. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most Common Cause overall:** *Chlamydia trachomatis* (presents at 5–14 days). * **Most Dangerous Cause:** *Neisseria gonorrhoeae* (presents early, 2–5 days; can penetrate intact corneal epithelium). * **Chemical Conjunctivitis:** Occurs within the first 24 hours; typically caused by Silver Nitrate itself. * **Incubation Periods:** * Chemical: <24 hours * Gonococcal: 2–5 days * Chlamydial: 5–14 days * Herpes Simplex: 1–2 weeks

Question 258: An 'A' pattern squint is typically associated with weakness or overaction of which extraocular muscle?

A. Superior rectus
B. Inferior rectus
C. Superior oblique (Correct Answer)
D. Inferior oblique

Explanation: **Explanation:** In pediatric ophthalmology, alphabet patterns (A or V) refer to a change in the horizontal deviation (esotropia or exotropia) as the patient moves their eyes from upward to downward gaze. **1. Why Superior Oblique is Correct:** An **'A' pattern** is defined as a horizontal deviation that increases in upward gaze and decreases in downward gaze (or an exodeviation that increases in downgaze). This pattern is most commonly associated with **Superior Oblique (SO) overaction**. * **Mechanism:** The SO muscle is a primary depressor, but its secondary action is **abduction**. When the SO is overactive, its abducting effect becomes most pronounced in **depression (downward gaze)**, causing the eyes to diverge at the bottom, thus forming the shape of an 'A'. Conversely, **Inferior Oblique (IO) weakness** can also contribute to an 'A' pattern. **2. Analysis of Incorrect Options:** * **Inferior Oblique (D):** Overaction of the IO is the most common cause of a **'V' pattern**. Since the IO is an abductor in elevation, overaction causes the eyes to diverge more in upward gaze. * **Superior Rectus (A) & Inferior Rectus (B):** While vertical recti have secondary adducting actions, pattern strabismus is primarily attributed to the oblique muscles in standard clinical teaching. Rectus muscle involvement (e.g., lateral rectus palsy) usually results in different patterns or is secondary to oblique dysfunction. **Clinical Pearls for NEET-PG:** * **'A' Pattern:** Think **S**uperior muscles (SO overaction or SR underaction). Clinically significant if the difference between up-gaze and down-gaze is **≥ 10 prism diopters**. * **'V' Pattern:** Think **I**nferior muscles (IO overaction or IR underaction). Clinically significant if the difference is **≥ 15 prism diopters**. * **Mnemonic:** **"A"** has a peak at the top (convergence in up-gaze) and is caused by **S**uperior Obliques. **"V"** is open at the top (divergence in up-gaze) and is caused by **I**nferior Obliques.

Question 259: Diplopia is not a presenting feature in which of the following conditions?

A. Manifest squint
B. Paralytic squint
C. Latent squint (Correct Answer)
D. Anisometropia

Explanation: **Explanation:** The core concept behind this question is the presence or absence of **binocular single vision (BSV)** and the mechanism of **fusion**. **1. Why Latent Squint (Phoria) is the correct answer:** A latent squint is a condition where the deviation of the eyes is kept hidden by the powerful mechanism of **active sensory and motor fusion**. The eyes remain perfectly aligned under normal binocular conditions. Diplopia only occurs when the two eyes are not looking at the same object simultaneously. Since the eyes in a latent squint are aligned during normal viewing, the images fall on the fovea of both eyes, maintaining BSV and preventing diplopia. **2. Analysis of Incorrect Options:** * **Paralytic Squint:** This is the most common cause of acquired diplopia. Due to the paralysis of an extraocular muscle, the eyes cannot align in certain directions of gaze, causing the image to fall on a non-corresponding retinal point (fovea of one eye and extra-foveal point of the other). * **Manifest Squint (Tropia):** In adults with a sudden onset manifest squint, diplopia is a hallmark feature. In children, however, it may be absent due to the development of *suppression* or *amblyopia*. However, as a general clinical rule, manifest deviations are associated with diplopia unless compensatory mechanisms have developed. * **Anisometropia:** A significant difference in refractive error between the two eyes leads to **aniseikonia** (difference in image size). This prevents the brain from fusing the two images, leading to binocular double vision or discomfort. **Clinical Pearls for NEET-PG:** * **Cover-Uncover Test:** Used to differentiate between a manifest squint (Tropia) and a latent squint (Phoria). * **Maddox Wing:** The clinical instrument used to measure the degree of **latent squint** for near vision. * **Maddox Rod:** Used to measure **latent squint** for distance. * **Diplopia** is always **pathognomonic of paralytic squint** in the acute phase.

Question 260: The following light reflex is seen in a patient. How much is the deviation?

A. 45 PD (Correct Answer)
B. 90 PD
C. 30 PD
D. 90°

Explanation: ***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.

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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