Pediatric Ophthalmology and Strabismus Practice Questions

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

Pseudo squint. **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.

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

Schirmer test. 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.

Q: What is the most uncommon type of latent strabismus?

Cyclophoria. **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.

Q: Ocular lesions of rubella include all of the following except?

Congenital megalocornea. **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.

Q: What is the treatment of threshold retinopathy of prematurity?

Laser photocoagulation. **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.

Q: 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?

Retinoblastoma. ### 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.

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

Constant squint. **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.

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

Decreased visual acuity. **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.

Question 1

Large angle Kappa gives rise to which type of squint?

Accepted Answer

Pseudo squint

Answer

Manifest squint

Answer

Latent squint

Answer

Periodic squint

Question 2

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

Accepted Answer

Schirmer test

Answer

Synaptophore test

Answer

Hirschberg test

Answer

Prism bar reflex test

Question 3

What is the most uncommon type of latent strabismus?

Accepted Answer

Cyclophoria

Answer

Esophoria

Answer

Exophoria

Answer

Hyperphoria

Question 4

Ocular lesions of rubella include all of the following except?

Accepted Answer

Congenital megalocornea

Answer

Congenital cataract

Answer

Congenital glaucoma

Answer

Optic atrophy

Question 5

What is the treatment of threshold retinopathy of prematurity?

Accepted Answer

Laser photocoagulation

Answer

Slow reduction in oxygen

Answer

Retinal reattachment

Answer

Antioxidants

Question 6

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?

Accepted Answer

Retinoblastoma

Answer

Congenital cataract

Answer

Coats' disease

Answer

Persistent hyperplastic primary vitreous (PHPV)

Question 7

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

Accepted Answer

Constant squint

Answer

Intermittent squint

Answer

Alternate squint

Answer

Latent squint

Question 8

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

Accepted Answer

Retrolental fibroplasia

Answer

Congenital glaucoma

Answer

Microphthalmia

Answer

Coloboma

Question 9

All are true about paralytic squint except?

Accepted Answer

Amblyopia

Answer

Unequal fixation

Answer

Vertigo

Answer

Head tilt

Question 10

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

Accepted Answer

Decreased visual acuity

Answer

Diplopia

Answer

Limited movement of the eyeball

Answer

Change in head posture

Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus — MCQs

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