Pediatric Ophthalmology and Strabismus Practice Questions

Q: Which of the following muscles produce intorsion of the eyeball?

Superior rectus and superior oblique. To master extraocular muscle actions for NEET-PG, it is essential to categorize their movements into primary, secondary, and tertiary actions. ### **Explanation of the Correct Answer** The correct answer is **A (Superior rectus and superior oblique)**. The mnemonic **"SIN"** (Superior muscles are INtorsionists) is the gold standard for remembering this. Both the Superior Rectus (SR) and the Superior Oblique (SO) are responsible for rotating the 12 o'clock position of the cornea medially toward the nose (intorsion). * **Superior Oblique:** Intorsion is its **primary** action. * **Superior Rectus:** Intorsion is its **secondary** action (elevation is primary). ### **Analysis of Incorrect Options** * **B & C (Inferior muscles):** Using the mnemonic **"RAD"** (Recti are ADductors), we know that inferior muscles are **Extorsionists**. The Inferior Rectus (IR) and Inferior Oblique (IO) rotate the eye outward. * **D (Superior rectus and inferior oblique):** While the SR intorts, the IO is a powerful extortor. These two muscles act as antagonists regarding torsional movement. ### **NEET-PG High-Yield Clinical Pearls** 1. **The "SIN-RAD" Rule:** * **S**uperior muscles are **IN**torsionists. * **R**ecti muscles are **AD**ductors (except lateral rectus). * *Corollary:* Inferior muscles are Extorsionists; Obliques are Abductors. 2. **Primary Actions to Remember:** * **Superior Oblique:** Intorsion (Depression occurs only when the eye is adducted). * **Inferior Oblique:** Extorsion (Elevation occurs only when the eye is adducted). 3. **Clinical Correlation:** In **4th Nerve Palsy (Superior Oblique Palsy)**, the patient loses intorsion power. To compensate and prevent diplopia, they present with a characteristic **head tilt** toward the opposite shoulder to ocularly extort the unaffected eye.

Q: 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?

Anisometropic amblyopia. ### 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."

Q: Which of the following statements about retinoblastoma is false?

Evisceration is the primary treatment.. **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).

Q: What is the main function of the superior oblique muscle?

Intorsion. **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.

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

A newborn is usually myopic by -2 to -3 D.. **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).

Q: What is the common ocular manifestation in Trisomy 13?

Bilateral microphthalmos. **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.

Q: All of the following are true for retinoblastoma except?

Always unilateral. **Explanation:** Retinoblastoma is the most common primary intraocular malignancy of childhood. The statement **"Always unilateral"** is incorrect because approximately **25-30% of cases are bilateral**. **Why Option B is the correct answer (False statement):** Retinoblastoma can be either sporadic or heritable. While the majority (60%) are unilateral and sporadic, cases involving a germline mutation in the **RB1 gene** (located on chromosome 13q14) typically present with **bilateral** or multifocal tumors. Therefore, it is not "always" unilateral. **Analysis of other options:** * **Option A:** **Leucocoria** (white pupillary reflex) is indeed the most common presenting sign (approx. 60%), followed by strabismus. * **Option C:** About 6-10% of cases have a positive **family history**. These are usually autosomal dominant with high penetrance. * **Option D:** The average age of diagnosis is **18 months**. Most cases are diagnosed before the age of 3, making the 1-2 year age group the most common. **High-Yield Clinical Pearls for NEET-PG:** * **Knudson’s Two-Hit Hypothesis:** Explains the genetic basis (two mutations required). * **Pathology:** Look for **Flexner-Wintersteiner rosettes** (highly specific) and Homer-Wright rosettes. * **Diagnosis:** Primarily clinical and via **B-scan Ultrasound** (shows calcification). CT/MRI are used to check for optic nerve involvement or "Trilateral Retinoblastoma" (bilateral RB + Pinealoblastoma). * **Calcification:** Intraocular calcification in a child under 3 years is Retinoblastoma until proven otherwise.

Question 1

What is the most common cause of amblyopia?

Accepted Answer

Squint

Answer

Tobacco

Answer

Methyl Alcohol

Answer

Hypermetropia

Question 2

In paralytic squint, what is the relationship between the primary deviation and the secondary deviation?

Accepted Answer

The primary deviation is less than the secondary deviation.

Answer

The primary deviation is more than the secondary deviation.

Answer

The primary deviation is equal to the secondary deviation.

Answer

The relationship between primary and secondary deviation is variable.

Question 3

Which of the following muscles produce intorsion of the eyeball?

Accepted Answer

Superior rectus and superior oblique

Answer

Inferior rectus and inferior oblique

Answer

Inferior rectus and superior oblique

Answer

Superior rectus and inferior oblique

Question 4

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?

Accepted Answer

Anisometropic amblyopia

Answer

Organic amblyopia

Answer

Emmetropic amblyopia

Answer

Toxic amblyopia

Question 5

Which of the following statements about retinoblastoma is false?

Accepted Answer

Evisceration is the primary treatment.

Answer

It follows an autosomal dominant inheritance pattern.

Answer

Enucleation is a treatment option.

Answer

Radiotherapy can be used as a treatment.

Question 6

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

Accepted Answer

The squint angle between the two eyes remains constant for all directions of gaze.

Answer

The squint angle changes between the two eyes for all directions.

Answer

The squint angle remains constant in some directions of gaze.

Answer

None of the above is true.

Question 7

What is the main function of the superior oblique muscle?

Accepted Answer

Intorsion

Answer

Adduction

Answer

Elevation

Answer

Extorsion

Question 8

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

Accepted Answer

A newborn is usually myopic by -2 to -3 D.

Answer

Optic nerve is myelinated only up to the lamina cribrosa.

Answer

The orbit is more divergent than in an adult.

Answer

Apart from the macular area, the retina is fully differentiated.

Question 9

What is the common ocular manifestation in Trisomy 13?

Accepted Answer

Bilateral microphthalmos

Answer

Capillary hemangioma

Answer

Neurofibroma

Answer

Dermoid Cyst

Question 10

All of the following are true for retinoblastoma except?

Accepted Answer

Always unilateral

Answer

Leucocoria is the most common presentation

Answer

May have family history

Answer

Most common age group affected is 1-2 years

Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus — MCQs

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