Pediatric Ophthalmology and Strabismus Practice Questions

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 is true about Retinoblastoma?

There may be a family history.. **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.

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

White pupil. **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).

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

Congenital dacryocystitis. **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.

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.

Question 1

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 2

Which of the following statements is true about Retinoblastoma?

Accepted Answer

There may be a family history.

Answer

Leukocoria is the most common presentation.

Answer

It always presents as unilateral.

Answer

Enucleation is the only treatment.

Question 3

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 4

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 5

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

Accepted Answer

White pupil

Answer

Blue sclera

Answer

No iris

Answer

Subluxed lens

Question 6

What is the main function of the superior oblique muscle?

Accepted Answer

Intorsion

Answer

Adduction

Answer

Elevation

Answer

Extorsion

Question 7

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

Accepted Answer

Congenital dacryocystitis

Answer

Mucopurulent conjunctivitis

Answer

Buphthalmos

Answer

Encysted mucocele

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

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

Accepted Answer

Bagolini striated glasses

Answer

Worth four dot test

Answer

Synoptophore

Answer

After image testing

Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus — MCQs

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