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 primary treatment for traumatic cataract in children?

Lensectomy. **Explanation:** The primary treatment for traumatic cataract in children is **Lensectomy**, often combined with an anterior vitrectomy. This approach is preferred because children have a highly reactive uveal tissue and a thick, elastic posterior capsule. Simple extracapsular techniques frequently lead to rapid development of **Posterior Capsule Opacification (PCO)** and severe inflammatory membranes, which are highly amblyogenic. Lensectomy (removal of the lens, including the capsule) ensures a clear visual axis, which is critical for preventing stimulus-deprivation amblyopia in the developing visual system. **Analysis of Options:** * **A. ECCE + IOL:** While standard in adults, ECCE in children carries a high risk of PCO and "Elschnig pearls." While IOLs are increasingly used in older children, the surgical priority in traumatic cases (especially with capsular rupture or vitreous loss) remains the clearance of the visual axis via lensectomy. * **C & D. Contact Lenses and Glasses:** These are methods for **refractive rehabilitation** (correcting aphakia) after the cataract has been surgically removed. They do not treat the cataract itself. **High-Yield Clinical Pearls for NEET-PG:** * **Amblyopia Risk:** The "golden period" for visual development is up to age 7-8. Any delay in treating a pediatric traumatic cataract leads to irreversible amblyopia. * **Surgical Technique:** In children <6 years, **Primary Posterior Capsulotomy (PPC)** and **Anterior Vitrectomy** are mandatory during cataract surgery to prevent PCO. * **Rosette Cataract:** The classic morphology of a traumatic cataract (concussion injury) is a flower-shaped or rosette cataract. * **Vossius Ring:** A circular ring of iris pigment on the anterior lens capsule, a pathognomonic sign of blunt trauma.

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: Oculocardiac reflex is seen in which surgery?

Strabismus surgery. **Explanation:** The **Oculocardiac Reflex (OCR)**, also known as the **Aschner-Dagnini reflex**, is a trigemino-vagal reflex triggered by pressure on the eyeball or traction on the extraocular muscles. **Why Strabismus Surgery is the correct answer:** Strabismus surgery involves significant manipulation and traction of the extraocular muscles (most commonly the **medial rectus**). This traction stimulates the long and short ciliary nerves, sending afferent signals via the **Ophthalmic division of the Trigeminal nerve (CN V1)** to the ciliary ganglion and then to the sensory nucleus of the trigeminal nerve. The efferent limb is carried by the **Vagus nerve (CN X)**, leading to bradycardia, arrhythmias, or even cardiac arrest. **Analysis of Incorrect Options:** * **Cataract Surgery:** While OCR can theoretically occur during any orbital procedure (like peribulbar blocks), it is significantly less common than in strabismus surgery because there is no direct traction on the extraocular muscles. * **VSD and Valvular Surgery:** These are cardiac surgeries. While they involve the heart, they do not involve the trigeminal-vagal pathway initiated by ocular stimulation. **High-Yield Clinical Pearls for NEET-PG:** * **Reflex Pathway:** Afferent = Trigeminal Nerve (V1); Efferent = Vagus Nerve (X). (Mnemonic: **5 and 10 reflex**). * **Clinical Presentation:** Bradycardia (most common), junctional rhythm, or asystole. * **Management:** The first step is to **stop the surgical stimulus** (release the muscle). If bradycardia persists, administer **Intravenous Atropine**. * **Fatigability:** The reflex is known to "fatigue" or diminish with repeated stimulation. * **Risk Factor:** Hypercarbia and acidosis increase the incidence of OCR.

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: How does retinoblastoma spread?

Optic nerve. **Explanation:** Retinoblastoma is the most common primary intraocular malignancy of childhood. The primary and most significant route of spread is via the **optic nerve**. **Why Optic Nerve is the Correct Answer:** The tumor cells invade the lamina cribrosa and travel along the optic nerve to reach the subarachnoid space. Once in the cerebrospinal fluid (CSF), the tumor can spread to the brain and leptomeninges. This is why the length of the optic nerve resected during enucleation is a critical prognostic factor; a "positive margin" at the cut end of the nerve significantly increases the risk of intracranial metastasis. **Analysis of Incorrect Options:** * **Vascular Invasion (A):** While retinoblastoma is highly vascular and can spread hematogenously to distant sites like bone marrow, lungs, and liver, this typically occurs later or in specific endophytic patterns. It is not the primary characteristic route compared to the optic nerve. * **Direct Invasion (B):** The tumor can grow through the sclera into the orbit (exophytic growth), but the sclera acts as a relatively tough natural barrier. This is less common than neural spread. * **Lymphatic Spread (D):** The eye lacks a traditional lymphatic drainage system. Lymphatic spread only occurs if the tumor involves the conjunctiva or eyelids, draining to the preauricular and submandibular nodes. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presentation:** Leukocoria (60%), followed by strabismus. * **Flexner-Wintersteiner Rosettes:** Pathognomonic histological feature (indicates photoreceptor differentiation). * **Homer-Wright Rosettes:** Seen in retinoblastoma but also in neuroblastoma and medulloblastoma. * **Calcification:** A hallmark sign on CT scan (helps differentiate from Coats' disease). * **Trilateral Retinoblastoma:** Bilateral RB associated with a pinealoblastoma.

Q: Amplitude of accommodative convergence is:

Altered by weak cycloplegics. **Explanation:** The **AC/A ratio (Accommodative Convergence/Accommodation)** represents the amount of convergence (in prism diopters) triggered by one diopter of accommodation. **Why Option A is Correct:** The AC/A ratio is a relatively stable, innate characteristic of the synkinetic reflex. However, it can be altered by drugs that affect the ciliary muscle. **Weak cycloplegics** (like Tropicamide or Homatropine) increase the AC/A ratio. This occurs because the drug induces a partial paralysis of the ciliary muscle; to achieve a specific amount of accommodation, the brain must send a much stronger neural signal (increased effort). Since convergence is linked to this neural effort rather than the physical change in the lens, the resulting convergence is disproportionately high. **Analysis of Incorrect Options:** * **Option B:** Lenses and prisms change the *demand* for accommodation or convergence, but they do not change the underlying AC/A ratio (the relationship between the two). * **Option C:** While the **amplitude of accommodation** decreases significantly with age (Presbyopia), the **AC/A ratio** remains remarkably constant throughout life until the very late stages of presbyopia. * **Option D:** Orthoptic exercises (like pencil push-ups) improve the *fusional* convergence (the ability to maintain single vision) but do not change the innate AC/A ratio. **High-Yield Clinical Pearls for NEET-PG:** * **Normal AC/A Ratio:** 3:1 to 5:1. * **High AC/A Ratio:** Often associated with **Accommodative Esotropia**. * **Gradient Method:** The most accurate way to measure the AC/A ratio using lenses. * **Miotics (e.g., Pilocarpine):** These *decrease* the AC/A ratio because they facilitate peripheral accommodation, requiring less central effort.

Question 1

A patient presented with his head tilted towards the left. On examination, he was having left hypertropia which increased on looking towards the right or medially. Which muscle is most likely paralyzed?

Accepted Answer

Left superior oblique

Answer

Left inferior oblique

Answer

Right superior oblique

Answer

Right inferior oblique

Question 2

Which of the following statements is FALSE regarding Duane's retraction syndrome?

Accepted Answer

Narrowing of the palpebral fissure on attempted adduction

Answer

Fibrous tightening of lateral or medial rectus muscles

Answer

Congenital ocular motility defect

Answer

All of the above

Question 3

Large angle Kappa gives rise to which type of squint?

Accepted Answer

Pseudo squint

Answer

Manifest squint

Answer

Latent squint

Answer

Periodic squint

Question 4

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 5

What is the primary treatment for traumatic cataract in children?

Accepted Answer

Lensectomy

Answer

Extra-capsular cataract extraction with intraocular lens implantation (ECCE + IOL)

Answer

Contact lens

Answer

Glasses

Question 6

Ocular lesions of rubella include all of the following except?

Accepted Answer

Congenital megalocornea

Answer

Congenital cataract

Answer

Congenital glaucoma

Answer

Optic atrophy

Question 7

Oculocardiac reflex is seen in which surgery?

Accepted Answer

Strabismus surgery

Answer

Cataract surgery

Answer

Ventricular Septal Defect surgery

Answer

Valvular surgery

Question 8

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 9

How does retinoblastoma spread?

Accepted Answer

Optic nerve

Answer

Vascular invasion

Answer

Direct invasion

Answer

Lymphatic spread

Question 10

Amplitude of accommodative convergence is:

Accepted Answer

Altered by weak cycloplegics

Answer

Altered by lenses and prisms

Answer

Decreased in older people

Answer

Altered by orthoptics

Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus — MCQs

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