Pediatric Ophthalmology and Strabismus Practice Questions

Q: A child presents with a unilateral white reflex and raised intraocular pressure (IOP). What are the required investigations?

All of the above. ### Explanation The clinical presentation of a **unilateral white reflex (leukocoria)** associated with **raised intraocular pressure (IOP)** in a child is a classic red flag for **Retinoblastoma**. In pediatric patients, leukocoria necessitates an urgent and thorough workup to differentiate life-threatening malignancies from other conditions like Coats' disease or persistent fetal vasculature. **Why "All of the Above" is Correct:** Managing a child with suspected intraocular pathology requires a multi-modal approach, often under **Examination Under Anesthesia (EUA)** because children are typically non-compliant with slit-lamp or formal fundus exams. * **Ultrasonography (USG B-Scan):** This is the most crucial initial imaging tool. It helps identify an intraocular mass and is highly sensitive for detecting **calcification** (the "pathognomonic" sign of Retinoblastoma). * **Observation Under Anesthesia (EUA):** This allows for a detailed 360-degree evaluation of the retina using indirect ophthalmoscopy and scleral depression to determine the size and extent of the tumor. * **Tonometry:** Since the patient has raised IOP (secondary glaucoma), measuring the pressure (using a Schiotz or Perkins tonometer) is essential to assess the severity of the disease and the risk of optic nerve damage or extraocular extension. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Leukocoria:** Congenital Cataract. * **Most common intraocular malignancy in children:** Retinoblastoma. * **Secondary Glaucoma in Retinoblastoma:** Usually occurs due to neovascularization of the iris (NVI) or forward displacement of the lens-iris diaphragm by a large endophytic mass. * **Imaging Gold Standard:** While USG is the first-line, **MRI** is the investigation of choice to check for optic nerve involvement or intracranial (trilateral) extension. **CT is generally avoided** due to radiation risk in children with the RB1 mutation.

Q: For preventing Retinopathy of Prematurity, what concentration of oxygen should be maintained?

50-60%. **Explanation:** Retinopathy of Prematurity (ROP) is a vasoproliferative disorder affecting the incomplete vascularization of the retina in preterm infants. The primary pathophysiology involves two phases: initial hyperoxia causing vaso-obliteration, followed by relative hypoxia triggering compensatory but pathological neovascularization. **Why 50-60% is the correct answer:** In clinical practice, the goal is to balance the prevention of ROP with the prevention of respiratory distress syndrome and cerebral hypoxia. For a premature infant requiring supplemental oxygen, maintaining an inspired oxygen concentration (FiO2) of **50-60%** is considered the threshold to prevent the severe hyperoxic insult that triggers ROP, while ensuring systemic stability. This range is historically cited in standard ophthalmology textbooks (like Khurana) as the target for preventing ROP. **Analysis of Incorrect Options:** * **A (20-30%) & B (30-40%):** These concentrations are often insufficient for premature infants with underdeveloped lungs (surfactant deficiency), leading to systemic hypoxia and increased mortality. * **D (60-70%):** Concentrations above 60% significantly increase the risk of oxygen toxicity, leading to both ROP and Bronchopulmonary Dysplasia (BPD). **High-Yield Clinical Pearls for NEET-PG:** * **Target SpO2:** Modern neonatal guidelines (SUPPORT trial) recommend maintaining oxygen saturation between **85-93%** or **91-95%**; however, for exam purposes, the FiO2 concentration remains a classic question. * **Screening Criteria:** Infants with birth weight **<1500g** or gestational age **<32 weeks** must be screened. * **First Screening:** Should be done at **4 weeks** post-natal age or **31 weeks** post-menstrual age (whichever is later). * **Zone I** involvement is the most severe. * **Plus Disease:** Characterized by dilatation and tortuosity of retinal vessels at the posterior pole; it is a key indicator for treatment.

Q: Which childhood malignancy commonly produces proptosis?

All of the above. **Explanation:** Proptosis (protrusion of the eyeball) in children is a critical clinical sign that often indicates an underlying malignancy, either through direct orbital involvement or metastatic spread. * **Neuroblastoma:** This is the **most common metastatic orbital tumor** in children. It typically originates from the adrenal glands or sympathetic chain. Metastasis to the orbital bones (specifically the zygomatic bone) leads to rapid-onset proptosis, often accompanied by characteristic periorbital ecchymosis known as **"Raccoon eyes."** * **Retinoblastoma:** While primarily an intraocular tumor, advanced cases can exhibit **extraocular extension**. Once the tumor breaches the sclera or invades the optic nerve, it enters the orbital space, leading to significant proptosis and a fungating mass. * **Nephroblastoma (Wilms Tumor):** Although less common than neuroblastoma, Wilms tumor is a known primary site that can metastasize to the orbit, resulting in secondary proptosis. **Clinical Pearls for NEET-PG:** * **Most common primary orbital malignancy in children:** Rhabdomyosarcoma (presents with sudden, painless proptosis). * **Most common intraocular tumor in children:** Retinoblastoma (presents with Leukocoria). * **Most common cause of bilateral proptosis in children:** Thyroid Eye Disease (though rare) or Neuroblastoma (metastatic). * **Differential Diagnosis Tip:** If a child presents with rapid proptosis and bruising, always prioritize Neuroblastoma in your differentials. If it presents with a "cherry-red" appearance and rapid growth, think Rhabdomyosarcoma.

Q: Pseudorosettes are a characteristic histological finding in which of the following conditions?

Retinoblastoma. **Explanation:** **Retinoblastoma** is the most common intraocular malignancy of childhood. Histologically, it is characterized by the presence of rosettes, which represent attempts at retinal differentiation. The correct answer is **Retinoblastoma** because it classically exhibits two types of rosettes: 1. **Homer-Wright Rosettes (Pseudorosettes):** These consist of tumor cells arranged around a central tangle of neural fibrils (no central lumen). They are "pseudo" because they lack a true basement membrane or lumen. They are also seen in neuroblastoma and medulloblastoma. 2. **Flexner-Wintersteiner Rosettes (True Rosettes):** These are highly specific for retinoblastoma, featuring cells arranged around a central empty lumen. **Analysis of Incorrect Options:** * **B. Ophthalmic nodosa:** A granulomatous inflammatory reaction caused by caterpillar hairs (urshiol) entering the eye. Histology shows granulomas, not rosettes. * **C. Phacolytic glaucoma:** An inflammatory glaucoma caused by the leakage of lens proteins through an intact capsule in a hypermature cataract. Histology shows macrophages laden with lens material (eosinophilic) in the anterior chamber. * **D. Trachoma:** A chronic keratoconjunctivitis caused by *Chlamydia trachomatis*. Histology reveals **Leber cells** (large macrophages containing phagocytosed debris) and lymphoid follicles. **High-Yield Clinical Pearls for NEET-PG:** * **Most specific finding:** Flexner-Wintersteiner rosettes. * **Most common sign:** Leukocoria (white pupillary reflex). * **Calcification:** Dystrophic calcification is a hallmark (visible on CT scan). * **Genetic association:** Mutation of the **RB1 gene** on Chromosome **13q14**. * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pinealoblastoma.

Q: What is the inheritance pattern of familial retinoblastomas?

Autosomal dominant. **Explanation:** **1. Why Autosomal Dominant is Correct:** Retinoblastoma is caused by a mutation in the **RB1 gene** located on chromosome **13q14**. While the cellular mechanism of the RB1 gene is recessive (both alleles must be inactivated for a tumor to form, as per **Knudson’s Two-Hit Hypothesis**), the **inheritance pattern** of familial retinoblastoma is **Autosomal Dominant**. This is because an individual inheriting one mutated allele has such a high probability (nearly 90% penetrance) of acquiring a second somatic mutation in any retinal cell that the disease manifests in every generation. **2. Why Other Options are Incorrect:** * **Autosomal Recessive:** Though the gene is a tumor suppressor (recessive at the molecular level), the pedigree shows dominant transmission because the "second hit" is almost inevitable. * **X-linked Dominant/Recessive:** The RB1 gene is located on an autosome (Chromosome 13), not on the sex chromosomes (X or Y). Therefore, it affects males and females equally and can be passed from father to son. **3. Clinical Pearls for NEET-PG:** * **Knudson’s Two-Hit Hypothesis:** In familial cases, the 1st hit is germline (inherited) and the 2nd is somatic. In sporadic cases, both hits are somatic. * **Clinical Presentation:** The most common sign is **Leukocoria** (white pupillary reflex), followed by strabismus. * **Bilateralism:** Familial cases are typically **bilateral and multifocal**, whereas sporadic cases are usually unilateral. * **Associated Tumors:** Patients with familial RB1 mutations are at a higher risk for secondary non-ocular tumors, most commonly **Osteosarcoma**. * **Trilateral Retinoblastoma:** Bilateral RB associated with a pineal gland tumor (Pineoblastoma).

Q: Hereditary retinoblastomas develop the following chromosomal deletion?

13q14. **Explanation:** **Retinoblastoma (RB)** is the most common primary intraocular malignancy of childhood. The genetic basis of this tumor lies in the mutation or deletion of the **RB1 gene**, which is a classic tumor suppressor gene. **1. Why 13q14 is Correct:** The RB1 gene is located on the **long arm (q)** of **chromosome 13** at the **band 14** (specifically 13q14.2). According to Knudson’s "Two-Hit Hypothesis," hereditary retinoblastoma occurs when a child inherits one defective copy of the RB1 gene (the first "hit" is germline) and subsequently acquires a mutation in the second allele (the second "hit" is somatic). In approximately 5–10% of cases, this genetic defect is visible as a cytogenetic deletion of the 13q14 region. **2. Why the other options are incorrect:** * **13p14:** The letter 'p' refers to the short arm (*petit*) of the chromosome. The RB1 gene is located on the long arm (q), not the short arm. * **14p13 / 14q13:** These options refer to Chromosome 14. While chromosomal abnormalities on 14 can be associated with other conditions, they have no primary association with the RB1 gene or Retinoblastoma. **Clinical Pearls for NEET-PG:** * **Inheritance:** Hereditary RB is typically **Autosomal Dominant** with high penetrance (90%). * **Presentation:** The most common sign is **Leukocoria** (white pupillary reflex), followed by strabismus. * **Histopathology:** Look for **Flexner-Wintersteiner rosettes** (pathognomonic, surrounding a central lumen) and Homer Wright rosettes. * **Trilateral Retinoblastoma:** This refers to bilateral RB associated with a pinealoblastoma (pineal gland tumor). * **Secondary Malignancies:** Patients with the germline 13q14 deletion are at a significantly higher risk of developing **Osteosarcoma** later in life.

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

All of the above statements are true.. Retinoblastoma is the most common primary intraocular malignancy of childhood. Understanding its genetic distribution is crucial for NEET-PG, as it follows Knudson’s "Two-Hit" Hypothesis. **Explanation of the Correct Answer:** All the provided statements are statistically accurate representations of the disease's epidemiology: * **Hereditary vs. Non-hereditary (40% vs. 60%):** Hereditary cases (40%) involve a germline mutation in the *RB1* gene (13q14). These patients are predisposed to bilateral tumors and secondary malignancies (like osteosarcoma). Non-hereditary cases (60%) occur due to somatic mutations and are always unilateral. * **Bilateral vs. Unilateral (30% vs. 70%):** While all bilateral cases are hereditary, not all hereditary cases present bilaterally (some remain unilateral due to incomplete penetrance). Thus, the clinical presentation is roughly 30% bilateral and 70% unilateral. * **Familial vs. Non-familial (6% vs. 94%):** This is a common point of confusion. While 40% are *hereditary* (germline mutation), only about 6% of patients have a positive *family history*. The remaining 34% of hereditary cases result from new (de novo) germline mutations. **Why other options are "wrong":** Since options A, B, and C are all factual clinical statistics regarding the inheritance and presentation of retinoblastoma, Option D is the only logical choice. **High-Yield Clinical Pearls for NEET-PG:** * **Most common sign:** Leukocoria (white pupillary reflex), followed by strabismus. * **Pathology:** Flexner-Wintersteiner rosettes (highly specific) and Homer-Wright rosettes. * **Calcification:** Dystrophic calcification is a hallmark; seen on CT scan as "intraocular calcification." * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pinealoblastoma. * **Treatment:** Chemoreduction (Vincristine, Etoposide, Carboplatin) is the current standard to shrink tumors before local therapy.

Question 1

Which of the following tests are appropriate for visual testing in a child?

Accepted Answer

Visual evoked potential and Teller's acuity card test

Answer

Visual evoked potential

Answer

Visual evoked potential and Keratometry

Question 2

A child presents with a unilateral white reflex and raised intraocular pressure (IOP). What are the required investigations?

Accepted Answer

All of the above

Answer

Ultrasonography (USG)

Answer

Observation under anesthesia

Answer

Tonometry

Question 3

For preventing Retinopathy of Prematurity, what concentration of oxygen should be maintained?

Accepted Answer

50-60%

Answer

20-30%

Answer

30-40%

Answer

60-70%

Question 4

Secondary deviation of the eye is based on which law?

Accepted Answer

Sherrington's law

Answer

Hering's law

Answer

Brown's law

Answer

Duane's law

Question 5

Diplopia is a characteristic feature of which type of squint?

Accepted Answer

Paralytic squint

Answer

Concomitant squint

Answer

Non-paralytic squint

Answer

Latent squint

Question 6

Which childhood malignancy commonly produces proptosis?

Accepted Answer

All of the above

Answer

Neuroblastoma

Answer

Retinoblastoma

Answer

Nephroblastoma

Question 7

Pseudorosettes are a characteristic histological finding in which of the following conditions?

Accepted Answer

Retinoblastoma

Answer

Ophthalmic nodosa

Answer

Phacolytic glaucoma

Answer

Trachoma

Question 8

What is the inheritance pattern of familial retinoblastomas?

Accepted Answer

Autosomal dominant

Answer

Autosomal recessive

Answer

X-linked dominant

Answer

X-linked recessive

Question 9

Hereditary retinoblastomas develop the following chromosomal deletion?

Accepted Answer

13q14

Answer

13p14

Answer

14p13

Answer

14p13

Question 10

Which of the following statements about retinoblastoma is FALSE?

Accepted Answer

All of the above statements are true.

Answer

Retinoblastomas are hereditary in 40% of cases and non-hereditary in 60%.

Answer

Retinoblastomas are bilateral in 30% of cases and unilateral in 70%.

Answer

Retinoblastomas are familial in 6% of cases and non-familial in 94%.

Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus — MCQs

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