Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus Indian Medical PG Practice Questions and MCQs

Question 101: Which of the following is NOT recommended for gonococcal eye prophylaxis?

A. 0.5% Erythromycin ophthalmic ointment
B. 1% silver nitrate ophthalmic ointment
C. 1% tetracycline ophthalmic ointment
D. Single-dose ceftriaxone 100mg/kg (Correct Answer)

Explanation: **Explanation:** The question asks for the agent **NOT** recommended for prophylaxis of gonococcal ophthalmia neonatorum. **1. Why Option D is the Correct Answer:** Systemic antibiotics like **Ceftriaxone** are used for the **treatment** of established gonococcal conjunctivitis, not for routine prophylaxis. Furthermore, the dose mentioned (100 mg/kg) is incorrect and potentially dangerous; if systemic treatment is required for a neonate, the standard dose is 25–50 mg/kg (not to exceed 125 mg). Routine prophylaxis is strictly topical. **2. Analysis of Incorrect Options (Recommended Prophylactic Agents):** * **0.5% Erythromycin ointment (Option A):** Currently the most widely recommended prophylactic agent globally due to its efficacy and low incidence of chemical irritation. * **1% Silver Nitrate (Option B):** Historically known as **Credé’s Method**. While effective against *N. gonorrhoeae*, it is less commonly used today because it frequently causes transient **chemical conjunctivitis** and is ineffective against *Chlamydia*. * **1% Tetracycline ointment (Option C):** An acceptable alternative to erythromycin for topical prophylaxis in many clinical guidelines. **3. High-Yield Clinical Pearls for NEET-PG:** * **Ophthalmia Neonatorum Timing:** * *Chemical:* Within 24 hours. * *Gonococcal:* 2–5 days (Most destructive; can cause corneal perforation). * *Chlamydial:* 5–14 days (Most common cause overall). * **Management:** If a mother has an untreated gonococcal infection at delivery, the neonate should receive a **single prophylactic dose** of Ceftriaxone (25–50 mg/kg IM/IV), but this is "preventative treatment" for high-risk exposure, not standard universal eye prophylaxis. * **Prophylaxis Limitation:** Topical prophylaxis (Erythromycin/Silver Nitrate) prevents Gonococcal infection but is **not effective** in preventing Chlamydial ophthalmia.

Question 102: What is the most common type of amblyopia?

A. Stimulus deprivation amblyopia
B. Anisometropic amblyopia
C. Strabismic amblyopia (Correct Answer)
D. Ametropic amblyopia

Explanation: **Explanation:** **Amblyopia** (lazy eye) is a unilateral or bilateral reduction in best-corrected visual acuity caused by abnormal visual experience early in life. **Why Strabismic Amblyopia is the correct answer:** **Strabismic amblyopia** is clinically recognized as the **most common type** of amblyopia. It occurs when there is a misalignment of the eyes (usually esotropia). To avoid diplopia (double vision) and visual confusion, the brain actively suppresses the image from the deviated eye. Constant suppression during the critical period of visual development leads to a permanent deficit in the visual cortex associated with that eye. **Analysis of Incorrect Options:** * **Anisometropic Amblyopia:** This is the second most common type. It occurs due to a significant difference in refractive error between the two eyes, leading to one blurred image and one clear image. The brain favors the clearer eye. * **Ametropic (Isoametropic) Amblyopia:** A less common bilateral form caused by high, uncorrected refractive errors in both eyes (e.g., high hyperopia), leading to blurred vision in both eyes. * **Stimulus Deprivation Amblyopia:** This is the **least common** but **most severe** form. It results from physical obstruction of the visual axis (e.g., congenital cataract, ptosis). If not treated urgently, it leads to irreversible vision loss. **High-Yield Clinical Pearls for NEET-PG:** * **Critical Period:** The period of visual plasticity is generally from birth to **7–8 years** of age. Treatment after this age is significantly less effective. * **Treatment Gold Standard:** Occlusion therapy (patching) of the **better eye** to force the use of the amblyopic eye. * **Penalization:** Using Atropine drops in the better eye to blur near vision is an alternative to patching. * **Crowding Phenomenon:** Amblyopic eyes often find it easier to see isolated letters than a row of letters.

Question 103: Phoria is a type of

A. Apparent squint
B. Manifest squint
C. Latent squint (Correct Answer)
D. Pseudo squint

Explanation: **Explanation:** **Phoria** is defined as a **latent squint** (Option C). In this condition, the visual axes are perfectly aligned under normal binocular viewing conditions due to the brain's strong desire for fusion. The deviation is "hidden" and only becomes manifest when the fusion reflex is disrupted, such as by covering one eye. **Why the other options are incorrect:** * **Apparent/Pseudo squint (Options A & D):** These terms are synonymous. They refer to a condition where the eyes *appear* misaligned (e.g., due to epicanthal folds or a wide interpupillary distance), but the visual axes are actually parallel. There is no true neuromuscular deviation. * **Manifest squint (Option B):** Also known as **Tropia**, this is a constant deviation where the visual axes are not parallel even when both eyes are open. The fusion mechanism is unable to overcome the deviation. **Clinical Pearls for NEET-PG:** * **Cover-Uncover Test:** This is the gold standard for differentiating between Phoria and Tropia. * In **Phoria**, the deviation is seen in the eye *under* the cover (it deviates when fusion is broken) and it moves back to the primary position when the cover is removed. * In **Tropia**, the *uncovered* eye moves to take up fixation when the deviating eye is covered. * **Maddox Wing:** Used to measure phorias for near vision. * **Maddox Rod:** Used to measure phorias for distant vision. * **Orthophoria:** The ideal state where the eyes remain parallel even when fusion is disrupted (rarely found in the general population).

Question 104: A 3-year-old male presents with sudden onset of visual loss in the left eye. Ophthalmological examination reveals strabismus and a white pupillary reflex. Fundus findings are as shown below. What is your diagnosis?

A. Retinoblastoma
B. Sickle cell retinopathy
C. Toxoplasmosis
D. Coats disease (Correct Answer)

Explanation: ***Coats disease*** - Classic presentation in **young males** with **unilateral leukocoria** and **strabismus**, along with **telangiectatic retinal vessels** and **subretinal exudates**. - Fundus shows characteristic **yellowish cholesterol deposits** and **vascular abnormalities** without calcification, distinguishing it from retinoblastoma. *Retinoblastoma* - Most common **intraocular malignancy** in children but typically shows **calcification** on imaging and **white chalky appearance** on fundus. - Would expect **family history** in hereditary cases and **bilateral involvement** in 40% of cases, not fitting this unilateral presentation. *Sickle cell retinopathy* - Requires underlying **sickle cell disease** with characteristic **sea fan neovascularization** and **arteriovenous anastomoses**. - Typically affects **older children and adults** with known hemoglobinopathy, not a 3-year-old with acute onset. *Toxoplasmosis* - Presents with **chorioretinitis** showing **fluffy white retinal lesions** with surrounding inflammation and **vitritis**. - Usually associated with **maternal infection** during pregnancy and shows **satellite lesions** near old scars, not the exudative pattern seen here.

Question 105: Regarding retinoblastoma, all of the following are true, EXCEPT?

A. Associated with 13q14 deletion
B. Inheritance is autosomal dominant
C. Approximately 25% of cases are bilateral (Correct Answer)
D. Approximately 40% of cases are heritable

Explanation: **Explanation:** The correct answer is **C** because the statement is factually incorrect. In Retinoblastoma, approximately **30–40% of cases are bilateral**, while 60–70% are unilateral. Bilateral cases are almost always heritable and associated with a germline mutation. **Analysis of Options:** * **A. Associated with 13q14 deletion:** This is true. Retinoblastoma is caused by a mutation or deletion in the **RB1 gene**, located on the long arm of chromosome 13 at position q14. * **B. Inheritance is autosomal dominant:** This is true for the heritable form. While the cellular mechanism is recessive (requiring "two hits"), the inheritance pattern in families follows an autosomal dominant trait with high penetrance (90%). * **D. Approximately 40% of cases are heritable:** This is true. About 40% of patients have a germline mutation (heritable), which predisposes them to bilateral involvement and secondary non-ocular tumors (like osteosarcoma). The remaining 60% are sporadic/somatic. **Clinical Pearls for NEET-PG:** * **Knudson’s Two-Hit Hypothesis:** Explains the occurrence of heritable (1st hit germline, 2nd hit somatic) vs. sporadic (both hits somatic) cases. * **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 feature seen on B-scan USG or CT scan (helps differentiate from Coats' disease). * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pinealoblastoma.

Question 106: Which of the following is associated with Retinoblastoma?

A. Intracranial calcification
B. Intraorbital calcification (Correct Answer)
C. Optic canal widening
D. Hydrocephalus

Explanation: **Explanation:** **Retinoblastoma** is the most common primary intraocular malignancy of childhood. The hallmark diagnostic feature of this tumor is **intraorbital calcification**, which occurs in approximately 90–95% of cases. 1. **Why Intraorbital Calcification is Correct:** The rapid proliferation of tumor cells often outstrips their blood supply, leading to coagulative necrosis. Within these necrotic areas, calcium salts are deposited (dystrophic calcification). On imaging (CT scan or Ultrasound B-scan), this appears as high-density or hyperechoic spots within the globe. In a child under 3 years old, intraorbital calcification is considered pathognomonic for Retinoblastoma until proven otherwise. 2. **Why Other Options are Incorrect:** * **Intracranial calcification:** While Retinoblastoma can spread to the brain or occur concurrently with a pineal tumor (Trilateral Retinoblastoma), calcification is primarily localized within the globe, not the intracranial space. * **Optic canal widening:** This is typically associated with **Optic Nerve Gliomas** (often seen in Neurofibromatosis Type 1), where the tumor grows along the nerve through the canal. * **Hydrocephalus:** This is a non-specific sign of increased intracranial pressure and is not a primary diagnostic feature of Retinoblastoma. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presentation:** Leukocoria (White pupillary reflex), followed by strabismus. * **Genetics:** Mutation in the **RB1 gene** on Chromosome **13q14**. * **Histopathology:** Look for **Flexner-Wintersteiner rosettes** (highly specific) and Homer-Wright rosettes. * **Imaging Modality of Choice:** **MRI** is preferred to evaluate optic nerve involvement and intracranial extension (Trilateral RB), but **CT** is superior for detecting calcification. * **Trilateral Retinoblastoma:** Bilateral RB associated with a pineal gland tumor (Pineoblastoma).

Question 107: A patient with Coats' disease presenting with leukocoria needs to be differentiated from which of the following conditions?

A. Retinoblastoma (Correct Answer)
B. Retinitis pigmentosa
C. Retinal detachment
D. Congenital cataract

Explanation: **Explanation:** **Coats' Disease** is an idiopathic condition characterized by telangiectatic and aneurysmal retinal vessels leading to massive subretinal exudation. When this exudation is extensive, it results in an exudative retinal detachment that appears as a white pupillary reflex (**leukocoria**). **1. Why Retinoblastoma is the correct answer:** Retinoblastoma is the most common intraocular malignancy of childhood and the most critical "must-rule-out" cause of leukocoria. Because Coats' disease typically presents in young males (unilaterally) with a white/yellowish mass behind the lens, it clinically mimics the endophytic growth pattern of Retinoblastoma. Differentiating the two is vital: Retinoblastoma often shows **calcification** on imaging (USG/CT), whereas Coats' disease is characterized by **cholesterol crystals** and lacks a solid soft tissue mass. **2. Why other options are incorrect:** * **Retinitis Pigmentosa:** Presents with night blindness and peripheral vision loss. Clinical findings include "bone-spicule" pigmentation and arteriolar attenuation, not leukocoria. * **Retinal Detachment:** While Coats' causes exudative detachment, rhegmatogenous retinal detachment in children is rare and usually associated with trauma or high myopia; it is a feature of the disease rather than the primary differential for the reflex itself. * **Congenital Cataract:** While a cause of leukocoria, the opacity is located within the **lens**, whereas Coats' and Retinoblastoma are **posterior segment** (retinal) pathologies. **Clinical Pearls for NEET-PG:** * **Coats' Disease:** Usually unilateral, 85% males, average age 8–10 years. "Light bulb" telangiectasia on angiography. * **Differential Diagnosis of Leukocoria (The "Big 5"):** Retinoblastoma, Coats' disease, Persistent Fetal Vasculature (PFV), Retinopathy of Prematurity (ROP), and Toxocariasis. * **Imaging:** USG B-scan is the first-line investigation to look for calcification (Pathognomonic for Retinoblastoma).

Question 108: What is the most common cause of epiphora in a newborn?

A. Stenosed lacrimal punctum
B. Non-canalisation of the nasolacrimal duct (Correct Answer)
C. Sinusitis
D. Ophthalmia neonatorum

Explanation: **Explanation:** The most common cause of epiphora (watering of the eyes) in a newborn is **Congenital Nasolacrimal Duct Obstruction (CNLDO)**, which occurs due to the **non-canalisation of the nasolacrimal duct**. The nasolacrimal system develops from a solid cord of ectoderm that canalizes throughout its length. The last portion to canalize is the lower end of the duct, specifically at the **Valve of Hasner**. If this membrane fails to canalize by birth, it results in a mechanical obstruction, leading to epiphora and recurrent crusting/discharge. **Analysis of Incorrect Options:** * **A. Stenosed lacrimal punctum:** While punctal agenesis or stenosis can cause epiphora, it is significantly rarer than NLD obstruction. * **C. Sinusitis:** This is an uncommon cause in newborns as the paranasal sinuses (especially frontal and sphenoid) are not fully developed at birth. * **D. Ophthalmia neonatorum:** This refers to neonatal conjunctivitis. While it causes discharge and redness, it is an acute infective condition rather than a structural cause of chronic epiphora. **High-Yield Clinical Pearls for NEET-PG:** * **Management:** 90% of cases resolve spontaneously by age 1. Initial treatment is **Crigler’s Massage** (lacrimal sac massage) and topical antibiotics if there is mucopurulent discharge. * **Surgical Timing:** If massage fails, **probing** is typically performed between 12–18 months of age. * **Differential Diagnosis:** Always rule out **Congenital Glaucoma** in a watering newborn eye, especially if photophobia, blepharospasm, or corneal haziness (buphthalmos) is present.

Question 109: Which two muscles are primarily responsible for the elevation of the eye?

A. Superior Rectus (SR) and Inferior Oblique (IO) (Correct Answer)
B. Inferior Oblique (IO) and Superior Oblique (SO)
C. Inferior Rectus (IR) and Superior Oblique (SO)
D. Superior Oblique (SO) and Superior Rectus (SR)

Explanation: **Explanation:** The vertical movements of the eye (elevation and depression) are governed by the coordinated action of the recti and oblique muscles. **1. Why Option A is Correct:** The **Superior Rectus (SR)** and the **Inferior Oblique (IO)** are the two primary elevators of the eye. * **Superior Rectus:** Its primary action is elevation. This action is most efficient when the eye is in a position of **abduction** (23°), as the visual axis aligns with the muscle's pull. * **Inferior Oblique:** Its primary action is excyclotorsion, but its secondary action is elevation. This elevation is most efficient when the eye is in a position of **adduction** (51°). Together, they ensure smooth upward movement across the entire horizontal field of gaze. **2. Why Other Options are Incorrect:** * **Option B & C:** The **Superior Oblique (SO)** and **Inferior Rectus (IR)** are primarily **depressors** of the eye. The SO is the main depressor in adduction, while the IR is the main depressor in abduction. * **Option D:** While the SR elevates, the SO acts as a depressor, making this combination functionally antagonistic in the vertical plane. **Clinical Pearls for NEET-PG:** * **RAD Rule:** **R**ecti are **AD**ductors (except Lateral Rectus). * **SIN Rule:** **S**uperior muscles are **IN**torters (Superior Rectus and Superior Oblique). * **Testing Position:** To isolate the **Superior Rectus**, ask the patient to look **up and out** (abduction). To isolate the **Inferior Oblique**, ask the patient to look **up and in** (adduction). * **Nerve Supply:** All extraocular muscles are supplied by the 3rd Cranial Nerve except the Superior Oblique (CN IV) and Lateral Rectus (CN VI) — Formula: **LR6(SO4)3**.

Question 110: All of the following are true regarding paralytic squint, except:

A. Head tilt
B. Lateral deviation
C. Diplopia
D. Amblyopia (Correct Answer)

Explanation: **Explanation:** The correct answer is **Amblyopia** because it is a characteristic feature of **non-paralytic (concomitant) squint**, not paralytic squint. **1. Why Amblyopia is the exception:** Amblyopia (lazy eye) typically develops in children during the "plastic period" of visual development (usually under age 7-8). In **paralytic squint**, the onset is usually sudden and occurs in adults or older children. Because the visual system is already mature, the brain cannot suppress the blurred image from the deviated eye, leading to persistent diplopia rather than amblyopia. **2. Analysis of other options:** * **Diplopia (C):** This is the hallmark of paralytic squint. Since the eyes are not aligned and the brain cannot suppress the second image, the patient experiences double vision, which is maximal in the direction of the paralyzed muscle's action. * **Head Tilt/Abnormal Head Posture (A):** Patients adopt a compensatory head posture (tilting, turning, or chin elevation/depression) to minimize diplopia by moving the eyes into a position where the paralyzed muscle is least required. * **Lateral Deviation (B):** Paralytic squint results in an objective deviation of the ocular axis (e.g., an abducens nerve palsy causes medial deviation, while a third nerve palsy causes lateral deviation/exotropia). **Clinical Pearls for NEET-PG:** * **Primary vs. Secondary Deviation:** In paralytic squint, the **secondary deviation** (measured with the paralyzed eye fixing) is always **greater** than the primary deviation (measured with the normal eye fixing) due to Hering’s Law of equal innervation. * **False Orientation (Past-pointing):** A classic sign of paralytic squint where the patient points beyond the object in the direction of the paralyzed muscle. * **Non-paralytic Squint:** Characterized by constant angle of deviation in all gazes, absence of diplopia, and high risk of amblyopia.

Practice by Chapter

Amblyopia

Practice Questions

Esotropia

Practice Questions

Exotropia

Practice Questions

Vertical Deviations

Practice Questions

Special Forms of Strabismus

Practice Questions

Nystagmus in Children

Practice Questions

Pediatric Cataract

Practice Questions

Retinopathy of Prematurity

Practice Questions

Pediatric Glaucoma

Practice Questions

Pediatric Neuro-ophthalmology

Practice Questions

Genetic Eye Diseases in Children

Practice Questions

Pediatric Ocular Trauma

Practice Questions

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