Free Board Certified Ophthalmologist Pediatric Ophthalmology and Strabismus Questions and Answers — Questions and Answers
Question 1: A 10-month-old infant presents with persistent tearing and mattering of the right eye since birth, consistent with congenital nasolacrimal duct obstruction (CNLDO). Conservative management with massage and topical antibiotics has failed to resolve the symptoms. According to current evidence, what is the most appropriate next step in management?
- Continue conservative management and re-evaluate at 18 months.
- Perform nasolacrimal duct probing under general anesthesia. (Correct answer)
- Perform a dacryocystorhinostomy (DCR).
- Place a Crawford tube without initial probing.
Correct answer: Perform nasolacrimal duct probing under general anesthesia.
Spontaneous resolution of CNLDO is high in the first year of life, but the rate plateaus after 9-10 months. Probing is a highly successful first-line surgical intervention, with success rates declining after 12-15 months. Therefore, for a 10-month-old who has failed conservative therapy, probing is the most appropriate next step. DCR is reserved for failed probings or complex cases, and placing a tube without probing is not the standard initial procedure.
Question 2: A 5-month-old infant is diagnosed with infantile esotropia. Which of the following clinical features is most characteristic of this condition?
- A small, intermittent deviation that resolves with hyperopic correction.
- A large-angle, constant esotropia (>30 prism diopters). (Correct answer)
- Profound unilateral amblyopia with a strong fixation preference.
- Marked limitation of abduction due to sixth nerve palsy.
Correct answer: A large-angle, constant esotropia (>30 prism diopters).
Infantile esotropia is defined by its onset before 6 months of age and is characterized by a large, constant angle of deviation, typically greater than 30 prism diopters. While amblyopia can occur, cross-fixation is common, leading to equal vision in many cases. The refractive error is usually only mildly hyperopic, and glasses do not correct the deviation. Apparent abduction deficits can be seen due to cross-fixation, but true palsies are not characteristic.
Question 3: According to the American Academy of Pediatrics and American Academy of Ophthalmology screening guidelines, which of the following infants requires screening examinations for retinopathy of prematurity (ROP)?
- An infant born at 33 weeks gestation with a birth weight of 1800 grams.
- An infant born at 31 weeks gestation with a birth weight of 1600 grams.
- An infant born at 29 weeks gestation with a birth weight of 1200 grams. (Correct answer)
- An infant born at 32 weeks gestation with a birth weight of 1550 grams.
Correct answer: An infant born at 29 weeks gestation with a birth weight of 1200 grams.
Current ROP screening guidelines recommend examinations for all infants with a birth weight of less than 1500 grams or a gestational age of 30 weeks or less. An infant born at 29 weeks with a birth weight of 1200 grams meets both of these criteria and definitively requires screening. The other infants listed fall outside these primary screening parameters.
Question 4: A 4-year-old child is diagnosed with moderate amblyopia (20/60) in the left eye due to strabismus. After prescribing the appropriate spectacle correction, you plan to initiate occlusion therapy. Based on the Pediatric Eye Disease Investigator Group (PEDIG) Amblyopia Treatment Studies, what is the most appropriate initial patching regimen?
- Full-time patching of the right eye.
- Patching the right eye for 6 hours per day.
- Patching the right eye for 2 hours per day. (Correct answer)
- Alternate-day patching of the right eye.
Correct answer: Patching the right eye for 2 hours per day.
The PEDIG Amblyopia Treatment Studies demonstrated that for moderate amblyopia (defined as 20/40 to 20/80) in children aged 3 to 7 years, patching the sound eye for 2 hours per day is as effective as patching for 6 hours per day. This less burdensome regimen improves compliance while achieving similar visual outcomes. Full-time or 6-hour patching is typically reserved for severe amblyopia or as a next step if 2-hour patching fails.
Question 5: A patient presents with a new-onset vertical diplopia and a compensatory right head tilt. Examination reveals a left hypertropia that worsens in right gaze and with a right head tilt. Using the Parks-Bielschowsky three-step test, which muscle is paretic?
- Right superior rectus
- Left inferior rectus
- Right inferior oblique
- Left superior oblique (Correct answer)
Correct answer: Left superior oblique
Step 1: A left hypertropia implicates weakness in a left eye depressor (inferior rectus, superior oblique) or a right eye elevator (superior rectus, inferior oblique). Step 2: The hypertropia worsens in right gaze, which isolates muscles with primary vertical action in adduction (left superior oblique) or abduction (right superior rectus). Step 3: The hypertropia worsens with a head tilt to the right (ipsilateral to the hypertropic eye's paretic intorter). During a right head tilt, the right eye intorts (RSR, RSO) and the left eye extorts (LIO, LIR). A weak left superior oblique (an intorter) would cause the left superior rectus to be unopposed, worsening the hypertropia. All three steps point to a left superior oblique palsy.
Question 6: A 4-month-old infant presents with nystagmus and profoundly poor vision. Parents report the infant frequently pokes and presses on their eyes with their fists. This behavior, known as the oculodigital sign, is a pathognomonic feature of which of the following conditions?
- Achromatopsia
- Congenital stationary night blindness
- Leber congenital amaurosis (LCA) (Correct answer)
- Infantile nystagmus syndrome
Correct answer: Leber congenital amaurosis (LCA)
The Franceschetti oculodigital sign, which involves eye poking, pressing, and rubbing, is a characteristic and pathognomonic finding in infants with Leber congenital amaurosis (LCA). This behavior is thought to create phosphenes (mechanical stimulation of the retina causing a sensation of light), which may be the only visual stimulation these severely visually impaired infants can experience. While nystagmus is present in the other conditions, the oculodigital sign is most strongly associated with LCA.
Free Board Certified Ophthalmologist Pediatric Ophthalmology and Strabismus Questions and Answers
A 10-month-old infant presents with persistent tearing and mattering of the right eye since birth, consistent with congenital nasolacrimal duct obstruction (CNLDO).
Conservative management with massage and topical antibiotics has failed to resolve the symptoms.
According to current evidence, what is the most appropriate next step in management?