Pediatric Ophthalmology and Strabismus — MCQs

A 3-year-old boy presents with a white reflex in the pupillary area and mild divergent squint in the right eye, noticed by family members for 4 months. Examination reveals leukocoria of the right eye with a dilated pupil non-reactive to light, secondary glaucoma, corneal edema, pseudohypopyon, and proptosis. USG B-scan, examination under anesthesia, and MRI of the region were performed. Which of the following is the most common histopathological finding seen in this condition?

Q57Medium

Strabismic amblyopia is more common in patients with which type of squint?

Q58Easy

Hyperoxygenation of premature infants may result in which of the following conditions?

Q59Easy

All are true about paralytic squint except?

Q60Easy

Which of the following is NOT a feature of paralytic squint?

Pediatric Ophthalmology and Strabismus Indian Medical PG Practice Questions and MCQs

Question 51: Large angle Kappa gives rise to which type of squint?

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

Explanation: **Explanation:** The correct answer is **Pseudo squint (A)**. **Concept of Angle Kappa:** Angle Kappa is the angle between the **visual axis** (line connecting the object of regard to the fovea) and the **pupillary axis** (line passing through the center of the pupil perpendicular to the cornea). * **Positive Angle Kappa:** The fovea is slightly temporal to the pupillary axis. A large positive angle kappa causes the eye to appear turned outward, mimicking **pseudo-exotropia**. * **Negative Angle Kappa:** The fovea is nasal to the pupillary axis. A large negative angle kappa causes the eye to appear turned inward, mimicking **pseudo-esotropia**. In both cases, the eyes are actually orthophoric (aligned), but the corneal light reflex is displaced, creating the illusion of a squint. **Analysis of Incorrect Options:** * **Manifest squint (B):** Also known as Heterotropia, this is a true misalignment of the visual axes where the eyes are not looking at the same point. * **Latent squint (C):** Also known as Heterophoria, this is a deviation kept in check by the fusion mechanism and is only revealed when one eye is covered. * **Periodic squint (D):** This refers to a true squint that occurs intermittently, often related to the degree of accommodation (e.g., accommodative esotropia). **Clinical Pearls for NEET-PG:** * **Pseudo-esotropia** is most commonly caused by **epicanthal folds** (common in Asian children) or a wide nasal bridge. * **Pseudo-exotropia** is most commonly caused by a **large positive angle kappa** (often seen in high hypermetropia or retinopathy of prematurity with macular dragging). * **Hirschberg Test:** In pseudo-squint, the corneal light reflex is centered or symmetrical, whereas in true squint, it is displaced.

Question 52: All of the following are useful in the measurement of the angle of deviation in squint EXCEPT?

A. Synaptophore test
B. Schirmer test (Correct Answer)
C. Hirschberg test
D. Prism bar reflex test

Explanation: In ophthalmology, the measurement of the angle of deviation is fundamental to diagnosing and managing strabismus (squint). **Why Schirmer Test is the Correct Answer:** The **Schirmer test** is used to measure **tear film production** and evaluate dry eye states (keratoconjunctivitis sicca). It involves placing a filter paper strip in the lower fornix and measuring the length of wetting over 5 minutes. It has no role in assessing ocular alignment or the angle of deviation. **Explanation of Incorrect Options:** * **Hirschberg Test (Corneal Light Reflex Test):** A quick, objective screening method where a light is shone into the eyes. The position of the reflex on the cornea estimates the deviation (e.g., 1mm displacement ≈ 7° or 15 prism diopters). * **Prism Bar Reflex Test (Krimsky Test):** Used when a patient has poor vision or fixation. Prisms of increasing strength are placed before the fixing eye until the corneal light reflex is centered in the deviating eye. * **Synaptophore:** A sophisticated instrument used to measure both objective and subjective angles of squint, as well as binocular single vision (BSV) grades (simultaneous perception, fusion, and stereopsis). **High-Yield Clinical Pearls for NEET-PG:** * **Hirschberg Formula:** 1mm = 7 degrees = 15 Prism Diopters (PD). * **Prism Cover Test:** The **gold standard** for measuring the angle of deviation, but requires good fixation and cooperation. * **Maddox Wing:** Used for measuring **heterophoria** (latent squint) for near vision. * **Maddox Rod:** Used for measuring the angle of deviation in phorias or tropias using a red streak of light.

Question 53: What is the most uncommon type of latent strabismus?

A. Esophoria
B. Exophoria
C. Hyperphoria
D. Cyclophoria (Correct Answer)

Explanation: **Explanation:** **Cyclophoria** is the correct answer because it is the rarest form of latent strabismus (heterophoria). It involves a latent tendency for the eye to rotate around its anteroposterior axis (torsional deviation), which is only revealed when binocular fusion is disrupted. Unlike horizontal or vertical deviations, the ocular motor system has a very limited compensatory mechanism for torsion, making significant cyclophoria clinically rare and often difficult to detect without specialized tests like the Maddox Wing or Double Maddox Rod. **Analysis of Incorrect Options:** * **Exophoria (B):** This is the **most common** type of latent strabismus, especially for near vision. It is a latent outward deviation of the eyes. * **Esophoria (A):** This is a latent inward deviation. It is very common, particularly in children with uncorrected hypermetropia due to the link between accommodation and convergence. * **Hyperphoria (C):** This is a latent vertical deviation. While less common than horizontal phorias, it is still significantly more prevalent in clinical practice than cyclophoria. **High-Yield Clinical Pearls for NEET-PG:** * **Definition:** Heterophoria (Latent Strabismus) is a condition where the deviation is kept in check by the fusion mechanism. It is elicited by the **Cover-Uncover Test**. * **Symptoms:** Most phorias are asymptomatic. When symptoms occur (due to fatigue or illness), it is termed **"Asthenopia"** (eye strain). * **Maddox Rod:** Used to detect horizontal and vertical phorias. * **Maddox Wing:** Used to detect and measure the degree of phoria for near fixation, including cyclophoria. * **Treatment:** Usually required only if symptomatic; involves correction of refractive errors, orthoptic exercises (for exophoria), or prisms.

Question 54: Ocular lesions of rubella include all of the following except?

A. Congenital megalocornea (Correct Answer)
B. Congenital cataract
C. Congenital glaucoma
D. Optic atrophy

Explanation: **Explanation:** Congenital Rubella Syndrome (CRS) is a classic topic for NEET-PG. The hallmark ocular finding in CRS is **Microphthalmos** (small eye) and **Microcornea**, which is the direct opposite of **Megalocornea** (Option A). Therefore, megalocornea is not a feature of rubella. **Why the other options are features of Rubella:** * **Congenital Cataract (Option B):** This is the most common ocular manifestation. It is typically pearly white and nuclear. The virus can persist inside the lens for years after birth. * **Congenital Glaucoma (Option C):** Occurs in about 10% of cases. It is clinically indistinguishable from primary infantile glaucoma and is caused by abnormal development of the anterior chamber angle. * **Optic Atrophy (Option D):** This can occur as a late complication, often secondary to prolonged glaucoma or as a result of viral-induced uveitis and neuroretinopathy. **High-Yield Clinical Pearls for NEET-PG:** 1. **"Salt and Pepper" Retinopathy:** This is the **most common** overall ocular sign of CRS. It involves pigmentary changes in the retina but usually does not affect vision. 2. **Gregg’s Triad:** The classic presentation of CRS includes **Cataract, Cardiac defects** (most commonly PDA), and **Deafness** (sensorineural). 3. **Differential Diagnosis:** While Rubella causes microcornea, **Congenital Syphilis** is associated with interstitial keratitis, and **Buphthalmos** (large eye) is the hallmark of primary congenital glaucoma. 4. **Surgery Caution:** In rubella cataracts, the virus remains live in the lens; surgery may release the virus, leading to severe postoperative endophthalmitis/uveitis.

Question 55: What is the treatment of threshold retinopathy of prematurity?

A. Laser photocoagulation (Correct Answer)
B. Slow reduction in oxygen
C. Retinal reattachment
D. Antioxidants

Explanation: **Explanation:** **Retinopathy of Prematurity (ROP)** is a vasoproliferative disorder affecting premature infants. The gold standard treatment for **Threshold ROP** is **Laser Photocoagulation** (Option A). **Why Laser Photocoagulation is correct:** Threshold ROP is defined by specific criteria (Stage 3 ROP in Zone I or II, involving 5 contiguous or 8 cumulative clock hours, with 'plus' disease). The underlying pathophysiology involves peripheral retinal ischemia, which triggers the release of Vascular Endothelial Growth Factor (VEGF). Laser photocoagulation ablates the **avascular peripheral retina**, thereby reducing the production of VEGF and preventing subsequent neovascularization, vitreous hemorrhage, and tractional retinal detachment. **Why other options are incorrect:** * **B. Slow reduction in oxygen:** While controlled oxygen delivery is a preventive strategy to reduce the risk of developing ROP, it is not a treatment for established threshold disease. * **C. Retinal reattachment:** This is reserved for Stage 4 or 5 ROP (Retinal Detachment). It is a late-stage surgical intervention, not the primary treatment for threshold disease. * **D. Antioxidants:** Vitamin E and other antioxidants have been studied for prevention, but they have no role in treating threshold ROP and may carry risks of toxicity. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Criteria:** Infants born at **≤30 weeks** gestation or **≤1500g** birth weight (or 1500-2000g with unstable clinical course). * **Timing:** First screening should occur at **4 weeks** post-natal age or **31 weeks** post-menstrual age (whichever is later). * **ETROP Study:** Shifted the treatment paradigm toward "Pre-threshold" (Type 1) ROP to improve outcomes. * **Alternative Treatment:** Intravitreal Anti-VEGF (e.g., Ranibizumab or Bevacizumab) is increasingly used, especially for Zone 1 disease.

Question 56: A 3-year-old boy presents with a white reflex in the pupillary area and mild divergent squint in the right eye, noticed by family members for 4 months. Examination reveals leukocoria of the right eye with a dilated pupil non-reactive to light, secondary glaucoma, corneal edema, pseudohypopyon, and proptosis. USG B-scan, examination under anesthesia, and MRI of the region were performed. Which of the following is the most common histopathological finding seen in this condition?

A. Retinoblastoma (Correct Answer)
B. Congenital cataract
C. Coats' disease
D. Persistent hyperplastic primary vitreous (PHPV)

Explanation: ### Explanation **1. Why Retinoblastoma is Correct:** The clinical presentation is a classic description of **Retinoblastoma (RB)**, the most common intraocular malignancy of childhood. The "white reflex" (**Leukocoria**) is the most common presenting sign (60%), followed by **strabismus**. The presence of **secondary glaucoma** (due to anterior displacement of the iris-lens diaphragm or neovascularization), **pseudohypopyon** (tumor cells settling in the anterior chamber), and **proptosis** (indicating extraocular extension) are advanced features of RB. MRI and USG B-scan are the gold standards for detecting **calcification**, a hallmark of this tumor. **2. Why Other Options are Incorrect:** * **Congenital Cataract:** While it is the most common cause of leukocoria, it does not present with pseudohypopyon, secondary glaucoma, or proptosis. * **Coats' Disease:** A vascular anomaly (telangiectatic vessels) leading to exudative retinal detachment. It usually affects slightly older boys (6–8 years) and lacks the calcification and aggressive extraocular spread seen here. * **PHPV (Persistent Fetal Vasculature):** Usually presents at birth in a **microphthalmic** eye. While it causes leukocoria, it does not typically present with proptosis or pseudohypopyon. **3. Clinical Pearls for NEET-PG:** * **Most common sign:** Leukocoria; **Second most common:** Strabismus. * **Pathognomonic Histology:** **Flexner-Wintersteiner rosettes** (specific for RB); Homer-Wright rosettes (non-specific, also seen in neuroblastoma). * **Calcification:** Seen in 90% of cases (detected as "high-echo" spots on B-scan). * **Inheritance:** Mutation in the **RB1 gene** on **Chromosome 13q14**. * **Pseudohypopyon:** In a child, always rule out Retinoblastoma before diagnosing uveitis. * **Contraindication:** **Fine Needle Aspiration Biopsy (FNAB)** is strictly contraindicated in suspected RB due to the risk of extraocular tumor seeding.

Question 57: Strabismic amblyopia is more common in patients with which type of squint?

A. Intermittent squint
B. Alternate squint
C. Constant squint (Correct Answer)
D. Latent squint

Explanation: **Explanation:** **1. Why Constant Squint is Correct:** Amblyopia (lazy eye) is a developmental reduction in visual acuity caused by abnormal visual experience early in life. In **constant squint**, one eye is permanently deviated, leading to persistent **diplopia** (double vision) and **confusion** (two different images falling on corresponding retinal points). To resolve this, the brain actively suppresses the image from the deviated eye. Because this suppression is continuous and occurs during the critical period of visual development, the visual pathways for that eye fail to mature, resulting in severe strabismic amblyopia. **2. Why Other Options are Incorrect:** * **Intermittent Squint:** The eyes are aligned some of the time, allowing for periods of normal binocular visual stimulation. This prevents permanent cortical suppression. * **Alternate Squint:** In this condition, the patient switches fixation between the two eyes (using the right eye then the left eye). Since both eyes receive stimulation and are used for fixation at different times, visual development remains relatively equal in both, and amblyopia does not develop. * **Latent Squint (Phoria):** This is a deviation kept in check by the fusion mechanism. The eyes remain straight under normal conditions, ensuring bifoveal fixation and preventing amblyopia. **Clinical Pearls for NEET-PG:** * **Critical Period:** The risk of amblyopia is highest from birth to age 7–8 years. * **Most Common Cause:** While strabismus is a major cause, **anisometropia** (unequal refractive error) is the most common cause of amblyopia overall. * **Treatment:** The mainstay of treatment is **occlusion therapy** (patching the "good" eye) to force the brain to use the amblyopic eye, ideally initiated before age 7.

Question 58: Hyperoxygenation of premature infants may result in which of the following conditions?

A. Congenital glaucoma
B. Microphthalmia
C. Coloboma
D. Retrolental fibroplasia (Correct Answer)

Explanation: **Explanation:** The correct answer is **Retrolental fibroplasia**, now more commonly known as **Retinopathy of Prematurity (ROP)**. **1. Why Retrolental Fibroplasia is correct:** In premature infants, the retinal vasculature is incompletely developed (vascularization normally reaches the nasal periphery at 8 months and temporal periphery at 1 month post-term). **Hyperoxygenation** (excessive supplemental oxygen) causes vasoconstriction of these immature vessels and suppresses Vascular Endothelial Growth Factor (VEGF). When the infant is later returned to room air, the retina becomes relatively hypoxic, leading to a massive overproduction of VEGF. This triggers **pathological neovascularization**. These fragile vessels can bleed and lead to fibrous scarring behind the lens (hence "retrolental fibroplasia"), eventually causing tractional retinal detachment. **2. Why the other options are incorrect:** * **A. Congenital glaucoma:** This is typically caused by developmental anomalies of the anterior chamber angle (trabeculodysgenesis), not oxygen levels. * **B. Microphthalmia:** This refers to an abnormally small eyeball, usually due to genetic mutations or intrauterine infections (e.g., TORCH), occurring during early organogenesis. * **C. Coloboma:** This is a structural defect caused by the failure of the embryonic optic fissure to close during the 5th–7th week of gestation. **Clinical Pearls for NEET-PG:** * **Screening Criteria:** In India, infants with birth weight **<1750g** or gestational age **<34 weeks** (or those with a stormy clinical course) must be screened for ROP. * **Timing:** The first screening should be done at **4 weeks** of postnatal age (or 3 weeks if born <28 weeks). * **Zone of Involvement:** Zone 1 (centered on the disc) is the most critical. * **Plus Disease:** Characterized by dilatation and tortuosity of posterior retinal vessels; it indicates active, severe ROP requiring urgent treatment (usually Laser photocoagulation or Anti-VEGF).

Question 59: All are true about paralytic squint except?

A. Unequal fixation
B. Vertigo
C. Amblyopia (Correct Answer)
D. Head tilt

Explanation: **Explanation:** In paralytic squint (paretic strabismus), the primary pathology is the weakness or paralysis of one or more extraocular muscles, usually due to a nerve palsy (III, IV, or VI). **Why Amblyopia is the Correct Answer (The "Except"):** Amblyopia (lazy eye) typically occurs during the "critical period" of visual development (birth to age 7–8) when the brain suppresses a blurred or deviated image to avoid diplopia. Paralytic squints are most commonly **acquired in adulthood** (due to trauma, diabetes, or hypertension). Because the visual system is already mature, the brain cannot suppress the second image, leading to persistent diplopia rather than amblyopia. Even in congenital cases, the frequent use of compensatory head postures usually maintains binocularity, making amblyopia rare. **Analysis of Incorrect Options:** * **Unequal Fixation:** This is a hallmark of paralytic squint. The **secondary deviation** (deviation of the sound eye when the paralyzed eye fixes) is always **greater** than the primary deviation due to Hering’s Law of equal innervation. * **Vertigo:** This occurs due to **false projection** and diplopia. When the patient looks in the direction of the paralyzed muscle, the spatial disorientation causes dizziness and nausea. * **Head Tilt (Compensatory Head Posture):** Patients instinctively tilt or turn their heads to minimize diplopia and bring the eyes into a position where the paralyzed muscle is not required (the "zone of comfort"). **High-Yield Clinical Pearls for NEET-PG:** * **Primary vs. Secondary Deviation:** Primary < Secondary (Paralytic); Primary = Secondary (Concomitant). * **Diplopia:** Maximum in the direction of the action of the paralyzed muscle. * **Bielschowsky’s Head Tilt Test:** Diagnostic for **Superior Oblique (IV Nerve) palsy**; the deviation increases when the head is tilted toward the affected side. * **False Projection:** The patient points beyond the object in the direction of the paralyzed muscle (past-pointing).

Question 60: Which of the following is NOT a feature of paralytic squint?

A. Diplopia
B. Decreased visual acuity (Correct Answer)
C. Limited movement of the eyeball
D. Change in head posture

Explanation: **Explanation:** In paralytic squint (incomitant strabismus), the primary pathology is the paralysis or paresis of one or more extraocular muscles, usually due to a nerve palsy (III, IV, or VI cranial nerves). **Why "Decreased Visual Acuity" is the correct answer:** Decreased visual acuity (amblyopia) is typically **not** a feature of paralytic squint. Paralytic squint usually occurs acutely in adults or older children whose visual systems are already developed. Because the eyes are misaligned, the patient experience diplopia rather than suppression. In contrast, **non-paralytic (concomitant) squint**, which starts in early childhood, leads to the brain suppressing the image from the deviated eye to avoid diplopia, resulting in amblyopia (lazy eye). **Analysis of Incorrect Options:** * **Diplopia (A):** This is the hallmark of paralytic squint. Since the onset is often sudden and the brain cannot suppress the second image, the patient sees double. * **Limited movement of the eyeball (C):** This is a defining feature. The deviation is maximal in the direction of the action of the paralyzed muscle (e.g., inability to abduct in VI nerve palsy). * **Change in head posture (D):** Patients adopt a **Compensatory Head Posture (CHP)**—turning, tilting, or tucking the chin—to minimize diplopia and place the eyes in a position where the paralyzed muscle is not required. **NEET-PG High-Yield Pearls:** 1. **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 sound eye fixing) due to Hering’s Law of equal innervation. 2. **False Orientation (Past-pointing):** Patients will point beyond the object in the direction of the paralyzed muscle. 3. **Nerve Involvement:** The 6th Nerve (Abducens) is the most common isolated cranial nerve palsy.

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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