Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus Indian Medical PG Practice Questions and MCQs

Question 161: A 16-year-old boy complains of pain in the right eye. After refractometry, he was prescribed a +3.5 D sphere lens. The cover test is normal. There is no heterophoria. What is the diagnosis?

A. Organic amblyopia
B. Anisometropic amblyopia (Correct Answer)
C. Emmetropic amblyopia
D. Toxic amblyopia

Explanation: ### Explanation **1. Why Anisometropic Amblyopia is Correct:** Amblyopia (lazy eye) is a decrease in best-corrected visual acuity due to abnormal visual development early in life. **Anisometropic amblyopia** occurs when there is a significant difference in refractive error between the two eyes. In this case, the patient has a refractive error of +3.5 D in the right eye (hypermetropia). If the other eye is emmetropic (normal) or has a significantly different power, the brain receives one clear image and one blurred image. To avoid diplopia or confusion, the brain suppresses the blurred image from the more ametropic eye, leading to amblyopia. The absence of heterophoria (latent squint) on the cover test confirms that the amblyopia is purely refractive/anisometropic rather than strabismic. **2. Why Other Options are Incorrect:** * **Organic Amblyopia:** This refers to visual loss due to an identifiable structural abnormality of the eye (e.g., optic atrophy or macular scarring). The question implies the vision loss is refractive. * **Emmetropic Amblyopia:** This is a contradictory term. Emmetropia refers to a perfect refractive state; amblyopia typically requires a "trigger" like refractive error, squint, or stimulus deprivation. * **Toxic Amblyopia:** This is usually bilateral and caused by exogenous substances (tobacco, alcohol, or drugs like ethambutol). It presents with central/centrocecal scotomas rather than isolated refractive errors. **3. Clinical Pearls for NEET-PG:** * **Amblyogenic Diopters:** Anisometropia leads to amblyopia if the difference is >1.5 D in Hypermetropia, >3.0 D in Myopia, or >1.5 D in Astigmatism. Hypermetropic anisometropia is the most amblyogenic. * **Sensitive Period:** The risk of developing amblyopia is highest from birth to age 7–8 years. * **Treatment:** The mainstay is "Optical Correction" (glasses) followed by "Occlusion Therapy" (patching the stronger eye) or "Atropine Penalization."

Question 162: Which of the following statements is true about Retinoblastoma?

A. Leukocoria is the most common presentation.
B. It always presents as unilateral.
C. There may be a family history. (Correct Answer)
D. Enucleation is the only treatment.

Explanation: **Explanation:** **1. Why the correct answer is right:** Retinoblastoma (RB) is the most common primary intraocular malignancy in children. It follows the **Knudson’s "Two-Hit" Hypothesis**. While 60% of cases are sporadic and non-heritable, approximately **40% are germline (heritable)**. In heritable cases, the first mutation is present in all cells (often inherited from a parent), and the second occurs in the retinal cells. Therefore, a positive family history is a significant clinical feature, particularly in bilateral or multifocal cases. **2. Why the other options are incorrect:** * **Option A:** While **Leukocoria** (white pupillary reflex) is the most common *sign* (60%), the question asks for a "true statement." While common, it is not the *only* presentation (Strabismus is the second most common). However, in many competitive exams, if "Leukocoria is the most common presentation" is an option alongside "There may be a family history," the latter is a more definitive genetic fact. *Note: In some textbooks, Leukocoria is indeed the most common presentation; however, in the context of this specific MCQ, the genetic component is the tested "true" fact.* * **Option B:** RB is **unilateral in 60-70%** of cases and **bilateral in 30-40%**. It does *not* always present as unilateral. * **Option D:** Enucleation is reserved for advanced stages (Group E). Modern management focuses on **eye-salvage therapies** such as systemic chemotherapy (Chemoreduction), Intra-arterial chemotherapy (IAC), cryotherapy, and plaque brachytherapy. **3. High-Yield Clinical Pearls for NEET-PG:** * **Gene:** RB1 gene located on **Chromosome 13q14**. * **Calcification:** Pathognomonic feature (seen on USG/CT as "fine specks"). * **Histology:** Look for **Flexner-Wintersteiner rosettes** (highly specific). * **Most common distant metastasis:** Bone marrow. * **Trilateral Retinoblastoma:** Bilateral RB associated with a pinealoblastoma.

Question 163: Which of the following statements about retinoblastoma is false?

A. It follows an autosomal dominant inheritance pattern.
B. Enucleation is a treatment option.
C. Radiotherapy can be used as a treatment.
D. Evisceration is the primary treatment. (Correct Answer)

Explanation: **Explanation:** The correct answer is **D**, as **evisceration is strictly contraindicated** in retinoblastoma. Evisceration involves removing the contents of the globe while leaving the sclera and optic nerve intact. In malignant tumors like retinoblastoma, this procedure would lead to the intraocular spread of tumor cells and orbital recurrence, significantly increasing mortality. **Analysis of Options:** * **A. Autosomal dominant inheritance:** This is true for heritable retinoblastoma (40% of cases). It follows the **Knudson’s Two-Hit Hypothesis**, where a germline mutation in the *RB1* gene (Chromosome 13q14) is inherited in a dominant fashion, though the cellular mechanism is recessive. * **B. Enucleation:** This is a standard treatment for advanced (Group E) tumors where there is no hope for vision. Unlike evisceration, enucleation involves removing the entire eyeball with a long segment of the optic nerve to prevent spread. * **C. Radiotherapy:** True. While being replaced by chemotherapy (chemoreduction) to avoid secondary malignancies, external beam radiotherapy or plaque brachytherapy remains a valid limb of treatment for specific cases. **High-Yield Clinical Pearls for NEET-PG:** * **Most common intraocular tumor** of childhood. * **Most common presentation:** Leukocoria (white pupillary reflex), followed by strabismus. * **Pathology:** Look for **Flexner-Wintersteiner rosettes** (highly specific) and Homer-Wright rosettes. * **Calcification:** Dystrophic calcification is a hallmark sign on CT scan (90% of cases). * **Trilateral Retinoblastoma:** Bilateral RB associated with a pineal gland tumor (Pineoblastoma).

Question 164: Which of the following is TRUE in a 2-year-old child with a left convergent concomitant squint?

A. The squint angle between the two eyes remains constant for all directions of gaze. (Correct Answer)
B. The squint angle changes between the two eyes for all directions.
C. The squint angle remains constant in some directions of gaze.
D. None of the above is true.

Explanation: ### Explanation The core concept tested here is the definition and clinical behavior of a **Concomitant (Non-paralytic) Squint**. **1. Why Option A is Correct:** In a **concomitant squint**, the neuromuscular mechanism of the extraocular muscles is intact, but the binocular coordination is lost. The defining characteristic of this condition is that the **angle of deviation remains constant** (or nearly constant) regardless of the direction of gaze or which eye is used for fixation. In this 2-year-old child with a left convergent squint (esotropia), the degree of inward deviation will not change whether the child looks up, down, left, or right. **2. Why Other Options are Incorrect:** * **Option B & C:** These describe **Incomitant (Paralytic or Restrictive) Squint**. In paralytic strabismus, the angle of deviation varies in different directions of gaze, usually increasing when the eye moves into the field of action of the paralyzed muscle. Since the question specifies the squint is "concomitant," these options are physiologically incorrect. **3. High-Yield Clinical Pearls for NEET-PG:** * **Concomitant vs. Incomitant:** In concomitant squint, the Primary Deviation (normal eye fixing) equals the Secondary Deviation (squinting eye fixing). In paralytic squint, the **Secondary Deviation is greater than the Primary Deviation**. * **Age of Onset:** Concomitant squints usually develop in early childhood (2–5 years), often associated with refractive errors (e.g., accommodative esotropia in hypermetropia). * **Diplopia:** Children with concomitant squint rarely complain of diplopia because they develop compensatory mechanisms like **suppression** or **amblyopia** (lazy eye). * **Management Priority:** The first step in managing a pediatric squint is always a **cycloplegic refraction** and a thorough **fundus examination** to rule out organic causes like retinoblastoma.

Question 165: Deletion of both Rb (retinoblastoma) genes in the same developing cell is most characteristically associated with the development of what condition?

A. Blue sclera
B. No iris
C. Subluxed lens
D. White pupil (Correct Answer)

Explanation: **Explanation:** The question describes the **Knudson’s "Two-Hit" Hypothesis**, which is the genetic hallmark of **Retinoblastoma**. Retinoblastoma is the most common primary intraocular malignancy of childhood. It occurs due to the inactivation of both alleles of the **RB1 tumor suppressor gene** located on chromosome **13q14**. When both genes are deleted or mutated in a retinal cell, uncontrolled proliferation leads to a retinal tumor. **Why "White Pupil" is correct:** The most common clinical presentation of Retinoblastoma (seen in over 60% of cases) is **Leukocoria**, also known as a **"White Pupillary Reflex."** This occurs because the white, vascularized mass of the tumor behind the lens reflects light back through the pupil, replacing the normal red reflex. **Why other options are incorrect:** * **Blue Sclera:** Associated with **Osteogenesis Imperfecta**, Ehlers-Danlos syndrome, or Buphthalmos (thinning of the sclera). * **No Iris (Aniridia):** A congenital bilateral condition often associated with **WAGR syndrome** (Wilms tumor, Aniridia, Genitourinary anomalies, and intellectual disability), involving the **PAX6 gene**, not the RB1 gene. * **Subluxed Lens:** Characteristically seen in **Marfan Syndrome** (superior-temporal) or **Homocystinuria** (inferior-nasal). **High-Yield Clinical Pearls for NEET-PG:** * **Second most common sign:** Strabismus (squint). * **Pathology:** Look for **Flexner-Wintersteiner rosettes** (highly specific) and **Homer-Wright rosettes**. * **Calcification:** Dystrophic calcification within the tumor is a classic feature seen on B-scan USG or CT. * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pineal gland tumor (Pineoblastoma). * **Inheritance:** 40% are heritable (germline mutation, usually bilateral); 60% are sporadic (somatic mutation, usually unilateral).

Question 166: What is the main function of the superior oblique muscle?

A. Adduction
B. Elevation
C. Extorsion
D. Intorsion (Correct Answer)

Explanation: **Explanation:** The superior oblique (SO) muscle is one of the two extraocular oblique muscles. To understand its function, one must consider its anatomical origin and insertion: it originates from the apex of the orbit, passes through the **trochlea** (a pulley-like structure), and inserts onto the posterior-superior-lateral quadrant of the globe. **1. Why Intorsion is the Correct Answer:** The primary action of any muscle is determined by its position relative to the visual axis when the eye is in the primary position. Because the SO inserts posterior to the equator and approaches the globe from the front (via the trochlea) at an angle of **51 degrees**, its main mechanical pull results in **Intorsion** (inward rotation of the 12 o'clock position of the cornea). **2. Analysis of Incorrect Options:** * **Adduction:** This is the primary action of the Medial Rectus. The SO actually acts as an **abductor** in the primary position. * **Elevation:** This is the primary action of the Superior Rectus. The SO acts as a **depressor**, especially when the eye is adducted. * **Extorsion:** This is the primary action of the **Inferior Oblique**. The superior muscles (Superior Rectus and Superior Oblique) are "Intorters," while inferior muscles are "Extorters." **3. NEET-PG High-Yield Clinical Pearls:** * **Mnemonic (SIN):** **S**uperior muscles are **IN**torters (Superior Oblique and Superior Rectus). * **Mnemonic (RAD):** Recti are ADductors (except Lateral Rectus). Therefore, **Obliques are ABductors**. * **SO Actions:** Primary: Intorsion; Secondary: Depression; Tertiary: Abduction. * **Nerve Supply:** The SO is supplied by the **4th Cranial Nerve (Trochlear)**. * **Clinical Sign:** In SO palsy (4th nerve palsy), patients present with **hypertropia** and compensatory **head tilting** to the opposite shoulder to minimize diplopia.

Question 167: A two-month-old child presents with epiphora and regurgitation. What is the most probable diagnosis?

A. Mucopurulent conjunctivitis
B. Buphthalmos
C. Congenital dacryocystitis (Correct Answer)
D. Encysted mucocele

Explanation: **Explanation:** The clinical presentation of **epiphora** (watering) and **regurgitation** of discharge on pressure over the lacrimal sac area in an infant is the classic hallmark of **Congenital Dacryocystitis (Congenital Nasolacrimal Duct Obstruction)**. 1. **Why it is correct:** The most common cause is a failure in the canalization of the nasolacrimal duct, typically due to a persistent **Valve of Hasner** at the lower end. This leads to stagnation of tears in the lacrimal sac, resulting in secondary infection. The "Regurgitation Test" (ROPLAS - Regurgitation on Pressure over Lacrimal Sac) is positive, confirming the diagnosis. 2. **Why other options are incorrect:** * **Mucopurulent conjunctivitis:** While it causes discharge, it does not typically present with a positive regurgitation test or localized swelling over the sac. * **Buphthalmos (Congenital Glaucoma):** Presents with the triad of epiphora, photophobia, and blepharospasm. However, it is characterized by an enlarged eyeball (corneal diameter >12mm) and corneal clouding, not regurgitation. * **Encysted mucocele:** This occurs when both the upper and lower ends of the lacrimal system are blocked (Amniotocele). It presents as a bluish swelling at birth but does not typically show regurgitation because the canaliculi are also obstructed. **High-Yield Clinical Pearls for NEET-PG:** * **Initial Management:** Digital massage (**Crigler’s maneuver**) and topical antibiotics. 90% of cases resolve spontaneously by age one. * **Surgical Timeline:** If massage fails, **Probing** is the treatment of choice (ideally at 1 year of age). If probing fails, Dacryocystorhinostomy (DCR) is usually deferred until age 4. * **Most common site of obstruction:** Valve of Hasner.

Question 168: All statements are true about the eye of a newborn except?

A. Optic nerve is myelinated only up to the lamina cribrosa.
B. The orbit is more divergent than in an adult.
C. Apart from the macular area, the retina is fully differentiated.
D. A newborn is usually myopic by -2 to -3 D. (Correct Answer)

Explanation: **Explanation:** The correct answer is **D**. A newborn is typically **hypermetropic**, not myopic. At birth, the average refractive error is approximately **+2.0 to +3.0 Diopters**. This occurs because the axial length of the newborn eye is short (about 16.5–17 mm). As the child grows, the eye undergoes "emmetropization," where the axial length increases and the corneal/lens power decreases to reach a neutral refractive state. **Analysis of other options:** * **Option A:** In a newborn, the optic nerve is indeed myelinated only up to the **lamina cribrosa**. Myelination starts centrally and reaches the globe at birth. If myelination continues intraocularly, it appears as "opaque nerve fibers," which is a clinical abnormality. * **Option B:** The orbital axes in a newborn are more **divergent** (approx. 50°) compared to an adult (approx. 45°). This contributes to the frequent observation of transient exodeviation in neonates. * **Option C:** At birth, the peripheral retina is well-developed, but the **macula is anatomically immature**. The foveal depression and differentiation of cones are not complete until approximately 4–6 months of age, which is why central fixation is not present at birth. **High-Yield Facts for NEET-PG:** * **Axial Length:** Newborn (~17 mm) → Adult (~24 mm). * **Corneal Diameter:** Newborn (~9.5–10 mm) → Adult (~11.5–12 mm). A diameter >11 mm in a newborn suggests infantile glaucoma (Buphthalmos). * **Lens:** The newborn lens is more spherical, contributing to high refractive power to compensate for the short axial length. * **Visual Acuity:** At birth, it is approximately 6/60 to 6/120 (Fixes on near objects).

Question 169: What is the common ocular manifestation in Trisomy 13?

A. Capillary hemangioma
B. Bilateral microphthalmos (Correct Answer)
C. Neurofibroma
D. Dermoid Cyst

Explanation: **Explanation:** **Trisomy 13 (Patau Syndrome)** is a severe chromosomal anomaly characterized by a failure of normal forebrain and midline facial development. The hallmark ocular manifestation is **bilateral microphthalmos**, which occurs due to the arrest of ocular development early in gestation. In severe cases, this can progress to **anophthalmos** (complete absence of the globe) or **cyclopia** (a single central eye). **Why the other options are incorrect:** * **Capillary hemangioma:** This is the most common benign orbital tumor of childhood but is typically an isolated finding or associated with PHACE syndrome, not Trisomy 13. * **Neurofibroma:** These are characteristic of Neurofibromatosis Type 1 (NF1). Specifically, plexiform neurofibromas give the classic "bag of worms" sensation on palpation. * **Dermoid Cyst:** These are choristomas commonly found at the superotemporal orbital rim. While common in children, they are not a defining feature of Patau syndrome. **High-Yield Clinical Pearls for NEET-PG:** * **Patau Syndrome Triad:** Microphthalmos, Cleft lip/palate, and Polydactyly. * **Key Histopathological Finding:** Intraocular **cartilage** (mesenchymal dysgenesis) is a highly specific finding in the microphthalmic eyes of Trisomy 13 patients. * **Other Ocular Findings:** Iris coloboma, persistent hyperplastic primary vitreous (PHPV), and retinal dysplasia. * **Differential:** Trisomy 18 (Edwards Syndrome) is more commonly associated with ptosis and corneal opacities rather than gross structural malformations like microphthalmos.

Question 170: Which is the least physiological test for binocular single vision (BSV)?

A. Worth four dot test
B. Bagolini striated glasses (Correct Answer)
C. Synoptophore
D. After image testing

Explanation: **Explanation:** The concept of "physiology" in binocular single vision (BSV) testing refers to how closely the test environment mimics natural viewing conditions. A **more physiological** test allows the patient to see the world normally without dissociating the eyes, while a **less physiological** test uses artificial filters or stimuli that disrupt natural fusion. **Why Bagolini Striated Glasses is the Correct Answer:** Bagolini striated glasses are considered the **most physiological** test for BSV. They consist of clear lenses with microscopic striations that produce a thin line of light. Because the lenses are transparent, the patient views the background naturally (minimal dissociation). This allows for the detection of BSV or suppression under near-normal viewing conditions. *Note: If the question asks for the **least** physiological test, the answer is **Synoptophore** or **After Image Testing**. There appears to be a discrepancy in the provided key; Bagolini is the **most** physiological, while the Synoptophore and After Image tests are the **least** physiological.* **Analysis of Options:** * **Bagolini Striated Glasses:** **Most physiological.** Minimal dissociation; clear background visibility. * **Worth Four Dot Test:** **Less physiological** than Bagolini. It uses red-green goggles, which significantly alter the patient's color perception and create a moderately dissociated environment. * **Synoptophore:** **Highly non-physiological.** It uses a mechanical device with tubes and bright lights, completely dissociating the eyes and removing natural peripheral fusion cues. * **After Image Testing (Hering’s):** **Least physiological.** It uses a bright flash to create a cortical imprint (after-image). It does not test BSV under real-world conditions but rather assesses retinal correspondence (ARC vs. NRC). **Clinical Pearls for NEET-PG:** * **Hierarchy of Physiology (Most to Least):** Bagolini > Worth 4 Dot > Synoptophore > After Image Test. * **Bagolini Glasses:** Best for detecting **Small Angle Esotropia** and **Microtropia** because they don't disrupt the fragile binocularity present. * **After Image Test:** The gold standard for determining the type of **Retinal Correspondence**.

Practice by Chapter

Amblyopia

Practice Questions

Esotropia

Practice Questions

Exotropia

Practice Questions

Vertical Deviations

Practice Questions

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

Practice Questions

Pediatric Ocular Trauma

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