Pediatric Ophthalmology and Strabismus — MCQs

A 2-week-old infant presents with excessive tearing in the left eye, overflow of tears in the lower eyelid, and frequent appearance of mucoid material for the last week. The baby was delivered at home to a multigravida mother who had regular antenatal visits. There were no maternal or fetal complications perinatally. What is the most appropriate next step in management?

Q157Easy

The Reese-Ellsworth classification is used for which condition?

Q158Easy

Which of the following muscles produce intorsion of the eyeball?

Q159Medium

A 5-year-old boy presents with leukocoria in the right eyeball, diagnosed as retinoblastoma involving the entire eyeball. The other eye has 2-3 small lesions in the periphery. What is the ideal management for this patient?

Q160Easy

Ophthalmic examination to screen for retinopathy of prematurity is mandatory for newborns with birth weight less than?

Pediatric Ophthalmology and Strabismus Indian Medical PG Practice Questions and MCQs

Question 151: Which of the following statements about Retinoblastoma is true?

A. It is inherited in 50% of cases.
B. It is caused by deletion of 11q14.
C. Rosettes suggest good prognosis. (Correct Answer)
D. It causes death in 60% of sufferers in the UK.

Explanation: **Explanation:** **Retinoblastoma (RB)** is the most common primary intraocular malignancy of childhood. The correct statement is that **Rosettes suggest a good prognosis**. 1. **Why Option C is Correct:** Histologically, RB presents with two types of rosettes: **Flexner-Wintersteiner rosettes** (highly specific, representing photoreceptor differentiation) and **Homer-Wright rosettes** (less specific). The presence of these rosettes indicates a higher degree of cellular differentiation. In oncology, well-differentiated tumors generally carry a better prognosis compared to undifferentiated (anaplastic) tumors. 2. **Why Other Options are Incorrect:** * **Option A:** Only **40%** of cases are heritable (germline mutation). The remaining 60% are sporadic/non-heritable. * **Option B:** RB is caused by a mutation or deletion in the **RB1 gene** located on chromosome **13q14**, not 11q14. It follows Knudson’s "Two-Hit" hypothesis. * **Option D:** With modern management (chemotherapy, plaque brachytherapy, and enucleation), the survival rate in developed countries like the UK is over **95%**. High mortality is only seen in resource-limited settings due to delayed presentation. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presenting sign:** Leukocoria (White pupillary reflex) > Strabismus. * **Calcification:** Pathognomonic feature seen on USG/CT scan (differentiates it from Coats' disease). * **Trilateral Retinoblastoma:** Bilateral RB associated with a pinealoblastoma. * **Risk of secondary malignancies:** Patients with the heritable form are at high risk for **Osteosarcoma** later in life. * **Flexner-Wintersteiner rosettes** surround a central lumen, whereas **Homer-Wright rosettes** surround a central fibrillar meshwork.

Question 152: Retrolental fibroplasia is due to which of the following?

A. Hypocapnia
B. CO2
C. Hypoxia
D. Hyperoxygenemia (Correct Answer)

Explanation: **Explanation:** **Retrolental Fibroplasia (RLF)**, now more commonly known as **Retinopathy of Prematurity (ROP)**, is a vasoproliferative disorder affecting preterm infants. **Why Hyperoxygenemia is Correct:** The primary trigger for ROP is the administration of high concentrations of supplemental oxygen (**Hyperoxygenemia**) to premature neonates. The pathophysiology occurs in two stages: 1. **Vaso-obliteration:** High oxygen levels cause the premature retinal vessels to constrict and cease growing (obliterate). 2. **Vasoproliferation:** When the infant is moved to room air, the previously obliterated areas become ischemic. This triggers the release of **VEGF (Vascular Endothelial Growth Factor)**, leading to neovascularization, vitreous hemorrhage, and tractional retinal detachment (the "retrolental" membrane). **Why Other Options are Incorrect:** * **Hypoxia:** While hypoxia occurs in the *second* phase of the disease (triggering VEGF), it is not the primary cause of the initial fibroplasia; rather, it is the relative drop from a hyperoxic state. * **CO2 / Hypocapnia:** While fluctuations in carbon dioxide levels (especially hypocapnia) can affect cerebral blood flow and are associated with periventricular leukomalacia, they are not the direct causative agents for the fibrovascular proliferation seen in RLF. **Clinical Pearls for NEET-PG:** * **Risk Factors:** Low birth weight (<1500g), low gestational age (<32 weeks), and prolonged oxygen therapy. * **Screening Rule:** In India, infants <34 weeks or <1750g (or those with stormy neonatal courses) must be screened. * **Timing:** The first screening should be done at **4 weeks** post-natal age or **31 weeks** post-menstrual age (whichever is later). * **Treatment:** Laser photocoagulation (Gold Standard) or Anti-VEGF injections (e.g., Ranibizumab). * **Zone I** involvement carries the worst prognosis.

Question 153: In paralytic squint, what is the relationship between the primary deviation and the secondary deviation?

A. The primary deviation is more than the secondary deviation.
B. The primary deviation is less than the secondary deviation. (Correct Answer)
C. The primary deviation is equal to the secondary deviation.
D. The relationship between primary and secondary deviation is variable.

Explanation: ### Explanation In paralytic squint, the fundamental physiological principle governing the difference between deviations is **Hering’s Law of Equal Innervation**. This law states that during any conjugate eye movement, an equal and simultaneous amount of nerve impulse is sent to the yoke muscles (e.g., the Right Lateral Rectus and Left Medial Rectus). **Why the correct answer is B:** * **Primary Deviation:** This is measured when the normal eye fixes on an object. The amount of innervation required is "normal," so the paretic eye deviates by a standard amount. * **Secondary Deviation:** This is measured when the **paretic eye** fixes on an object. Because the paretic muscle is weak, the brain must send an **excessive neural impulse** to move that eye into position. According to Hering’s Law, this same massive impulse is simultaneously sent to the yoke muscle of the healthy eye, causing it to overact significantly. Therefore, the secondary deviation is always greater than the primary deviation. **Analysis of Incorrect Options:** * **Option A:** This occurs in **concomitant (non-paralytic) squint**, where the angle of deviation remains constant regardless of which eye is fixing. * **Option C:** This is also a characteristic of concomitant squint, where there is no muscle paralysis and innervation is distributed normally. * **Option D:** The relationship is not variable; it is a consistent clinical finding used to differentiate paralytic from non-paralytic strabismus. **High-Yield Clinical Pearls for NEET-PG:** * **Hering’s Law** explains secondary deviation in paralytic squint. * **Sherrington’s Law** (Reciprocal Innervation) explains the relaxation of an antagonist muscle when the agonist contracts. * In **concomitant squint**, Primary Deviation = Secondary Deviation. * In **paralytic squint**, Secondary Deviation > Primary Deviation. * **Diplopia** in paralytic squint is maximal in the direction of the action of the paralyzed muscle.

Question 154: What is the ideal treatment for bilateral retinoblastoma?

A. Enucleation
B. Radiation (Correct Answer)
C. Chemotherapy
D. Cyclophotocoagulation

Explanation: **Explanation:** The primary goal in treating **bilateral retinoblastoma** is to preserve as much vision as possible while ensuring life-saving tumor control. **Why Radiation is the Correct Answer:** Historically and conceptually, **Radiation (External Beam Radiotherapy - EBRT)** is considered the classic treatment for bilateral cases because it is "eye-salvaging." Unlike enucleation, radiation can treat the entire retina, including occult vitreous seeds and multiple tumor foci, which are common in the heritable (bilateral) form. While modern protocols often start with chemoreduction to shrink tumors, radiation remains a definitive modality for vision preservation in bilateral disease. **Analysis of Incorrect Options:** * **A. Enucleation:** This involves the surgical removal of the eye. While it is the treatment of choice for advanced unilateral cases (Group E), it is avoided in bilateral cases unless one eye is completely disorganized (no potential for vision), as the goal is to prevent total blindness. * **C. Chemotherapy:** While "Chemoreduction" (using VEC protocol: Vincristine, Etoposide, Carboplatin) is frequently used to reduce tumor volume, it is often a precursor to local therapies (cryo/laser) or radiation rather than a standalone curative treatment for the entire disease process in this context. * **D. Cyclophotocoagulation:** This is a procedure used to treat refractory glaucoma by destroying the ciliary body; it has no role in the primary management of retinoblastoma. **High-Yield Clinical Pearls for NEET-PG:** * **Most common intraocular tumor of childhood:** Retinoblastoma. * **Genetics:** Mutation in the **RB1 gene** on Chromosome **13q14**. * **Clinical Sign:** **Leukocoria** (Amaurotic cat’s eye reflex) is the most common presentation, followed by strabismus. * **Pathology:** Look for **Flexner-Wintersteiner rosettes** (pathognomonic) and calcification on CT scan. * **Trilateral Retinoblastoma:** Bilateral RB associated with a pineal gland tumor (Pineoblastoma).

Question 155: The reciprocal inhibition of the antagonist muscle upon lateral gaze is explained by which law?

A. Sherrington's law (Correct Answer)
B. Hering's law
C. Laplace's law
D. Hick's law

Explanation: **Explanation:** The correct answer is **Sherrington’s Law of Reciprocal Innervation**. **1. Why Sherrington’s Law is Correct:** Sherrington’s law states that when an agonist muscle receives an increased nerve impulse to contract, there is a simultaneous and proportional decrease in the nerve impulse to its **antagonist muscle** in the **same eye**. * **Mechanism:** During lateral gaze (e.g., looking to the right), the right Lateral Rectus (agonist) contracts while the right Medial Rectus (antagonist) relaxes. This ensures smooth, coordinated movement without resistance from the opposing muscle. **2. Analysis of Incorrect Options:** * **Hering’s Law:** This law governs **yoke muscles** (muscles in opposite eyes that move the eyes in the same direction). It states that equal and simultaneous innervation is sent to the yoke muscles (e.g., right Lateral Rectus and left Medial Rectus) during version movements. * **Laplace’s Law:** A principle of physics/cardiology relating the pressure within a hollow viscus (like the heart or alveoli) to the wall tension and radius. It is not related to ocular motility. * **Hick’s Law:** A psychological principle describing the time it takes for a person to make a decision as a result of the possible choices. **3. High-Yield Clinical Pearls for NEET-PG:** * **Sherrington’s Law** applies to **Monocular** movements (one eye). * **Hering’s Law** applies to **Binocular** movements (both eyes). * **Clinical Application:** Sherrington’s law is the basis for **Duane’s Retraction Syndrome**, where co-contraction of the medial and lateral recti occurs due to aberrant innervation, leading to globe retraction—a failure of reciprocal inhibition. * **Hering’s Law** explains "Secondary Deviation" in paralytic squint, where the deviation is greater when the paralyzed eye fixes because of increased innervation sent to both eyes.

Question 156: A 2-week-old infant presents with excessive tearing in the left eye, overflow of tears in the lower eyelid, and frequent appearance of mucoid material for the last week. The baby was delivered at home to a multigravida mother who had regular antenatal visits. There were no maternal or fetal complications perinatally. What is the most appropriate next step in management?

A. Nasolacrimal sac massaging (Correct Answer)
B. Probing of nasolacrimal duct
C. Application of erythromycin drops
D. Instillation of steroid drops

Explanation: ### **Explanation** The clinical presentation of excessive tearing (epiphora), tear overflow, and mucoid discharge in a 2-week-old infant is classic for **Congenital Nasolacrimal Duct Obstruction (CNLDO)**. This condition most commonly occurs due to a failure of canalization at the distal end of the nasolacrimal duct, specifically at the **Valve of Hasner**. #### **Why Option A is Correct** **Nasolacrimal sac massage (Crigler’s maneuver)** is the first-line management for CNLDO. The technique involves applying downward pressure over the lacrimal sac to create hydrostatic pressure, which helps rupture the membranous obstruction at the Valve of Hasner. Approximately **90% of cases resolve spontaneously** within the first year of life with conservative management (massage and lid hygiene). #### **Why Other Options are Incorrect** * **B. Probing:** While effective, probing is typically reserved for cases that fail to resolve with massage after the age of **10–12 months**. Performing it at 2 weeks is premature and carries unnecessary anesthetic risk. * **C. Erythromycin drops:** Topical antibiotics are only indicated if there is active purulent conjunctivitis. They treat the secondary infection but do not address the underlying mechanical obstruction. * **D. Steroid drops:** These have no role in treating a mechanical obstruction and can cause side effects like secondary glaucoma or cataracts in infants. #### **NEET-PG High-Yield Pearls** * **Most common site of obstruction:** Valve of Hasner (distal end of NLD). * **Conservative Management:** Crigler’s massage (10 strokes, 4 times a day) is the gold standard until 1 year of age. * **Surgical Timeline:** * **1 year:** Probing (success rate ~90%). * **Subsequent failures:** Intubation with silicone tubes or Balloon Dacryocystoplasty. * **3–4 years:** Dacryocystorhinostomy (DCR) is the definitive surgery if other measures fail. * **Differential Diagnosis:** Always rule out **Congenital Glaucoma**, which presents with a triad of epiphora, photophobia, and blepharospasm, along with an enlarged cornea (buphthalmos).

Question 157: The Reese-Ellsworth classification is used for which condition?

A. Rhabdomyosarcoma
B. Retinoblastoma (Correct Answer)
C. Optic nerve sheath tumor
D. Meningioma

Explanation: The **Reese-Ellsworth classification** was historically the primary system used to predict the prognosis for **eye salvage** (vision preservation) in patients with **Retinoblastoma** treated with external beam radiotherapy (EBRT). ### Why Retinoblastoma is Correct Retinoblastoma is the most common intraocular malignancy of childhood. The Reese-Ellsworth system (developed in the 1960s) categorizes tumors into five groups (Group I to V) based on: * **Tumor size** (measured in disc diameters). * **Location** (at or behind the equator). * **Number of tumors.** * **Presence of vitreous seeding.** *Group I represents a very favorable prognosis, while Group V represents a very unfavorable prognosis for saving the eye.* ### Why Other Options are Incorrect * **Rhabdomyosarcoma:** This is the most common primary orbital malignancy in children. It is staged using the **IRS (Intergroup Rhabdomyosarcoma Study)** grouping system, not Reese-Ellsworth. * **Optic Nerve Sheath Tumor (Meningioma/Glioma):** These are classified based on anatomical location and histopathological grading (WHO classification). * **Meningioma:** Specifically, Sphenoid wing or orbital meningiomas are classified based on their surgical extent and histological grade. ### High-Yield Clinical Pearls for NEET-PG * **Current Trend:** The Reese-Ellsworth classification has largely been replaced by the **International Classification of Retinoblastoma (ICRB)**, which better predicts success with modern **chemotherapy** (chemoreduction) rather than radiotherapy. * **Most Common Sign:** Leukocoria (white pupillary reflex). * **Genetics:** Mutation in the **RB1 gene** on chromosome **13q14**. * **Pathology:** Look for **Flexner-Wintersteiner rosettes** (highly specific) and Homer-Wright rosettes. * **Calcification:** Retinoblastoma is the most common cause of intraocular calcification in a child under 3 years old.

Question 158: Which of the following muscles produce intorsion of the eyeball?

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

Explanation: 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.

Question 159: A 5-year-old boy presents with leukocoria in the right eyeball, diagnosed as retinoblastoma involving the entire eyeball. The other eye has 2-3 small lesions in the periphery. What is the ideal management for this patient?

A. Enucleation of both eyes
B. Enucleation of the right eye and conservative management of the other eye
C. Enucleation of the right eye and focal therapy of the other eye (Correct Answer)
D. 6 cycles of chemotherapy

Explanation: ### Explanation The management of retinoblastoma (RB) is tailored to the stage of the disease in each eye, aiming first to save life, then the globe, and finally vision. **1. Why Option C is Correct:** In this case, the patient has bilateral retinoblastoma with asymmetrical involvement. * **Right Eye:** The tumor involves the "entire eyeball" (Group E classification). When a tumor is so extensive that there is no hope for vision or a high risk of extraocular spread, **Enucleation** is the gold standard. * **Left Eye:** The presence of "2-3 small lesions in the periphery" suggests early-stage disease (Group A or B). These lesions are amenable to **Focal Therapy** (such as cryotherapy or laser photocoagulation), which preserves the globe and vision. **2. Why Other Options are Incorrect:** * **Option A:** Enucleation of both eyes is avoided unless both eyes have advanced (Group E) disease with no visual potential. It causes permanent total blindness and is psychologically devastating. * **Option B:** "Conservative management" is too vague. Small peripheral lesions require active intervention (focal therapy) to prevent progression; simple observation is not appropriate. * **Option D:** While systemic chemotherapy (Chemoreduction) is used to shrink tumors, it is typically reserved for cases where globe salvage is being attempted in both eyes or for metastatic disease. It would not replace the need for enucleation in a completely involved Group E eye. **Clinical Pearls for NEET-PG:** * **Most common intraocular malignancy in children:** Retinoblastoma. * **Most common presentation:** Leukocoria (60%), followed by strabismus. * **Classification:** The International Classification for Intraocular Retinoblastoma (ICIR) groups eyes from A (small) to E (very advanced). * **Genetics:** Most bilateral cases are **germline mutations** (RB1 gene on chromosome 13q14) and carry a risk of secondary tumors (e.g., Osteosarcoma). * **Pathology:** Flexner-Wintersteiner rosettes are pathognomonic.

Question 160: Ophthalmic examination to screen for retinopathy of prematurity is mandatory for newborns with birth weight less than?

A. 1000 grams
B. 1500 grams (Correct Answer)
C. 2000 grams
D. 2500 grams

Explanation: ### Explanation **1. Why 1500 grams is correct:** Retinopathy of Prematurity (ROP) is a vasoproliferative disorder affecting the incomplete vascularization of the retina in preterm infants. According to the **National Neonatology Forum (NNF) of India** and international guidelines (like AAP), screening is mandatory for infants with a **birth weight ≤ 1500 grams** or a **gestational age ≤ 30 weeks**. These infants are at the highest risk because their retinal vessels have not reached the periphery (ora serrata), making them vulnerable to hypoxia-induced overproduction of VEGF (Vascular Endothelial Growth Factor) and subsequent abnormal neovascularization. **2. Why the other options are incorrect:** * **A (1000 grams):** While "Extremely Low Birth Weight" (ELBW) infants (<1000g) are at the highest risk for aggressive ROP, using this as the cutoff would miss a significant number of "Very Low Birth Weight" (VLBW) infants who also develop treatable disease. * **C & D (2000g & 2500g):** These weights are generally too high for routine screening. However, in developing countries like India, screening is extended to infants between **1500–2000g** only if they have an unstable clinical course (e.g., prolonged oxygen therapy, sepsis, or blood transfusions). 2500g is considered a normal birth weight. **3. Clinical Pearls for NEET-PG:** * **Timing of First Screen:** Usually at **4 weeks (30 days)** of life. For very preterm infants (<28 weeks), it is done at 2–3 weeks of life. * **"When to Screen" Rule:** "30-30 Rule" (≤30 weeks gestation or ≤1500g birth weight). * **Plus Disease:** Characterized by dilatation and tortuosity of posterior pole retinal vessels; it is a key indicator for treatment. * **Treatment of Choice:** Laser photocoagulation (diode laser) of the avascular retina. Intravitreal Anti-VEGF (Ranibizumab/Bevacizumab) is an emerging alternative.

Practice by Chapter

Amblyopia

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Esotropia

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Exotropia

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Vertical Deviations

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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

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Pediatric Ocular Trauma

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