Pediatric Ophthalmology and Strabismus Practice Questions

Q: Which extraocular muscle is commonly lost during squint surgery?

Medial Rectus (MR). **Explanation:** The **Medial Rectus (MR)** is the most common muscle to be "lost" or slipped during squint surgery. A "lost muscle" occurs when the muscle detaches from the globe and retracts posteriorly into the orbital fat, often disappearing behind Tenon’s capsule. **Why the Medial Rectus?** 1. **Lack of Fascial Attachments:** Unlike the other recti, the MR lacks significant fascial connections to the oblique muscles or the orbital wall. For example, the Superior Rectus is attached to the Levator Palpebrae Superioris, and the Inferior Rectus is attached to the Inferior Oblique. 2. **Short Tendon:** The MR has a relatively short tendon, making it harder to grasp if it slips. 3. **Posterior Retraction:** Once detached, the MR tends to retract deep into the medial orbital space, making surgical retrieval difficult. **Analysis of Incorrect Options:** * **Lateral Rectus (LR):** While it can slip, it is less common than the MR because it has some stabilizing fascial attachments to the orbital wall (check ligaments). * **Superior Rectus (SR):** It is rarely lost because it is anatomically coupled with the **Levator Palpebrae Superioris (LPS)** muscle via a common fascial sheath. * **Superior Oblique (SO):** This muscle has a very long tendon and a unique course through the trochlea, making it nearly impossible to "lose" in the same manner as the recti. **High-Yield Clinical Pearls for NEET-PG:** * **Slipped Muscle vs. Lost Muscle:** A *slipped* muscle remains within its original capsule/sheath, whereas a *lost* muscle retracts out of its sheath. * **Clinical Sign:** A lost muscle results in a significant limitation of ocular motility in its field of action and a large secondary deviation. * **Management:** If a muscle is lost during surgery, the immediate step is to use the **Maddox wing** or imaging (CT/MRI) post-operatively to locate it. Surgical retrieval often requires an operating microscope.

Q: All of the following are causes of leukocoria except?

Coloboma of optic disc. **Explanation:** **Leukocoria**, or a "white pupillary reflex," occurs when an intraocular pathology reflects light back through the pupil instead of the normal red reflex. **Why Coloboma of the Optic Disc is the correct answer:** While a coloboma of the **choroid** is large enough to reflect light and cause a white reflex, a coloboma of the **optic disc** is typically too small and localized to the posterior pole to produce a generalized leukocoria. It usually presents with visual field defects or is discovered during routine fundoscopy rather than as a white pupil. **Analysis of Incorrect Options:** * **Retinoblastoma:** The most common primary intraocular malignancy in children and the **most common cause** of life-threatening leukocoria. It must be ruled out first in any child presenting with a white reflex. * **Retinopathy of Prematurity (ROP):** In advanced stages (Stage 4 and 5), cicatricial changes and total retinal detachment create a dense white retrolental membrane, leading to leukocoria. * **Coloboma of the Choroid:** This is a congenital defect in the fusion of the embryonic fissure. It results in a large area of bare, white sclera in the inferior fundus. Because of its significant surface area, it reflects light prominently, causing a clinical white reflex. **NEET-PG High-Yield Pearls:** * **Differential Diagnosis of Leukocoria (The "White Pupil"):** Remember the mnemonic **"CRUMB"** — **C**ataract (Congenital), **R**etinoblastoma/ROP, **U**veitis (Toxocariasis), **M**ers (Persistent Hyperplastic Primary Vitreous/PHPV), **B**eats (Coats’ Disease). * **Most common cause of Leukocoria:** Congenital Cataract. * **Most dangerous cause:** Retinoblastoma. * **Key distinction:** Choroidal coloboma is usually located **infero-nasally** (due to the site of embryonic fissure closure).

Q: In ophthalmology, what is the effect of muscle resection?

Strengthening of the muscle. In strabismus surgery, procedures are broadly classified into **strengthening** and **weakening** procedures. **Explanation of the Correct Answer:** **Resection** is a **strengthening procedure**. During this surgery, a segment of the extraocular muscle tendon or muscle belly is removed, and the remaining muscle is reattached to its original insertion site. This effectively shortens the muscle. According to the length-tension relationship, shortening the muscle increases its effective pull and rotational force on the globe, thereby "strengthening" its action. **Explanation of Incorrect Options:** * **A. Weakening of the muscle:** This is achieved through **Recession**. In recession, the muscle is detached and moved posteriorly from its original insertion, effectively slackening the muscle and reducing its pull. * **C. Muscle paralysis:** This is a pathological state (e.g., 3rd, 4th, or 6th nerve palsy) or can be temporarily induced by Botox injections, but it is not the intended physiological result of a resection. * **D. No effect:** Resection significantly alters the mechanical advantage of the muscle; it never results in "no effect." **High-Yield Clinical Pearls for NEET-PG:** * **Recession = Weakening:** Moving the muscle *backward* (e.g., Recess the Medial Rectus for Esotropia). * **Resection = Strengthening:** Shortening the muscle (e.g., Resect the Lateral Rectus for Esotropia). * **Faden Operation (Posterior Fixation Suture):** A unique procedure that weakens a muscle only in its field of action without changing the primary position. * **Inferior Oblique:** Most commonly managed by weakening procedures (recession, myectomy, or anteriorization) rather than resection.

Q: Amaurotic cat's eye reflex is not seen in which of the following conditions?

Glaucoma. **Explanation:** The **Amaurotic Cat’s Eye Reflex (Leukocoria)** refers to a whitish pupillary reflex instead of the normal red reflex. It occurs when an intraocular pathology reflects light back through the pupil. **Why Glaucoma is the Correct Answer:** In pediatric cases, **Congenital Glaucoma (Buphthalmos)** typically presents with a **cloudy or hazy cornea** due to edema, an enlarged eyeball, and photophobia. It does not involve an intraocular mass or membrane behind the lens; therefore, it does **not** cause a white pupillary reflex (Leukocoria). **Analysis of Incorrect Options:** * **Cataract:** Congenital cataract is one of the most common causes of leukocoria. The opacification of the crystalline lens directly blocks the red reflex, creating a white appearance. * **Cyclitic Membrane:** This is a layer of inflammatory fibrovascular tissue formed behind the lens (often following chronic endophthalmitis or trauma). This retrolental membrane reflects light, causing a cat's eye reflex. * **Retrolental Fibroplasia (Retinopathy of Prematurity):** In advanced stages (Stage 5), total retinal detachment and the formation of a dense fibrovascular mass behind the lens result in a classic white reflex. **NEET-PG High-Yield Pearls:** 1. **Most Common Cause of Leukocoria:** Congenital Cataract. 2. **Most Common Life-Threatening Cause:** Retinoblastoma (must be ruled out in every case of pediatric leukocoria). 3. **Differential Diagnosis (Mnemonic: "COATS"):** **C**ataract, **C**oats’ disease, **O**cular toxocariasis, **A**strocytic hamartoma, **T**ersons/Persistent **T**hyperplastic primary vitreous (PHPV), **S**carring (Retrolental fibroplasia). 4. **Glaucoma vs. Leukocoria:** Remember that Glaucoma causes a "Large Blue Eye" (due to scleral thinning/uveal show), not a "White Pupil."

Q: Duane syndrome involves dysfunction of which extraocular muscle?

Lateral rectus. **Explanation:** **Duane Retraction Syndrome (DRS)** is a congenital cranial dysinnervation disorder characterized by the **agenesis or hypoplasia of the Abducens nerve (CN VI) nucleus**. Because the Abducens nerve normally supplies the **Lateral Rectus (LR)**, this muscle is primarily affected. In DRS, the Lateral Rectus fails to receive its normal innervation. Instead, it is paradoxically innervated by branches from the **Oculomotor nerve (CN III)**. This leads to "co-contraction" of both the Medial Rectus and the Lateral Rectus during adduction, causing the classic clinical sign of **globe retraction** and narrowing of the palpebral fissure. **Analysis of Incorrect Options:** * **A & B (Superior/Inferior Oblique):** These muscles are involved in vertical and torsional movements. While "upshoots" or "downshoots" can occur in DRS due to the leash effect, the primary muscle dysfunction and the underlying neurogenic defect involve the LR. * **D (Superior Rectus):** This muscle is supplied by the Oculomotor nerve. While CN III is involved in the aberrant innervation of the LR in Duane syndrome, the Superior Rectus itself functions normally. **High-Yield Clinical Pearls for NEET-PG:** * **Huber’s Classification:** * **Type I (Most Common):** Limited abduction (most frequent). * **Type II:** Limited adduction. * **Type III:** Limited both abduction and adduction. * **Key Signs:** Globe retraction on adduction, narrowing of palpebral fissure, and compensatory head tilt. * **Association:** Often associated with **Goldenhar Syndrome**. * **Inheritance:** Mostly sporadic; if familial, it is usually Autosomal Dominant (DURS1/DURS2 genes).

Q: Extraretinal fibrovascular proliferation at the ridge between normal and avascular retina is characteristic of which grade of Retinopathy of Prematurity (ROP)?

Grade 3. **Explanation:** Retinopathy of Prematurity (ROP) is a vasoproliferative disorder of the retina in preterm infants. The International Classification of Retinopathy of Prematurity (ICROP) defines the severity of the disease through five distinct stages: * **Stage 3 (Correct Answer):** This stage is characterized by **extraretinal fibrovascular proliferation**. The hallmark is the growth of new, abnormal vessels (neovascularization) extending from the ridge into the vitreous. This is a critical stage as it indicates a high risk of progression to retinal detachment. **Analysis of Incorrect Options:** * **Stage 1:** Characterized by a thin, flat, white **demarcation line** separating the vascularized retina from the avascular retina. There is no height or thickness to this line. * **Stage 2:** The demarcation line progresses into a **ridge** that has height, width, and volume. However, the proliferation remains intraretinal (within the ridge). * **Stage 4:** Defined by **subtotal retinal detachment**. It is further divided into 4A (extra-foveal) and 4B (foveal involvement). Stage 5 represents total retinal detachment. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Criteria (India):** Birth weight **<1750g** or Gestational Age **<34 weeks**, or infants with an unstable clinical course. * **Screening Timing:** First screening should be done at **4 weeks** post-natal age (or 3 weeks if born <28 weeks). * **Plus Disease:** Characterized by arterial tortuosity and venous dilation in the posterior pole; it indicates active, severe disease. * **Treatment:** Laser photocoagulation or Anti-VEGF (Ranibizumab/Bevacizumab) is typically indicated for "Type 1 ROP" (e.g., Stage 3 with Plus disease in Zone I or II).

Question 1

All of the following are true about paralytic strabismus EXCEPT:

Accepted Answer

Primary deviation = Secondary deviation

Answer

Binocular diplopia

Answer

False orientation

Answer

False projection

Question 2

Dissociated vertical deviation is seen in which condition?

Accepted Answer

Congenital esotropia

Answer

AV dissociation

Answer

Infantile esotropia

Answer

Superior oblique palsy

Question 3

Brown's syndrome simulates paresis of which extraocular muscle?

Accepted Answer

Inferior oblique

Answer

Superior oblique

Answer

Superior rectus

Answer

Inferior rectus

Question 4

Which extraocular muscle is commonly lost during squint surgery?

Accepted Answer

Medial Rectus (MR)

Answer

Lateral Rectus (LR)

Answer

Superior Rectus (SR)

Answer

Superior Oblique (SO)

Question 5

All of the following are causes of leukocoria except?

Accepted Answer

Coloboma of optic disc

Answer

Coloboma of choroid

Answer

Retinopathy of prematurity

Answer

Retinoblastoma

Question 6

In ophthalmology, what is the effect of muscle resection?

Accepted Answer

Strengthening of the muscle

Answer

Weakening of the muscle

Answer

Muscle paralysis

Answer

No effect on the muscle

Question 7

Amaurotic cat's eye reflex is not seen in which of the following conditions?

Accepted Answer

Glaucoma

Answer

Cataract

Answer

Cyclitic membrane

Answer

Retrolental fibroplasia

Question 8

Defect in amblyopia lies in which structure?

Accepted Answer

Lateral geniculate body

Answer

Afferent pupillary reflex

Answer

Rods and cones

Answer

Retina

Question 9

Duane syndrome involves dysfunction of which extraocular muscle?

Accepted Answer

Lateral rectus

Answer

Superior oblique

Answer

Inferior oblique

Answer

Superior rectus

Question 10

Extraretinal fibrovascular proliferation at the ridge between normal and avascular retina is characteristic of which grade of Retinopathy of Prematurity (ROP)?

Accepted Answer

Grade 3

Answer

Grade 1

Answer

Grade 2

Answer

Grade 4

Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus — MCQs

On this page

Practice by Chapter

Want unlimited practice?