Board Certified Ophthalmologist Pediatric Ophthalmology and Strabismus Questions and Answers — Questions and Answers
Question 1: A 4-month-old infant presents with a constant, large-angle esotropia of 50 prism diopters that has been present since birth. Cycloplegic refraction reveals +2.00 D sphere in both eyes. The fundus exam is normal. What is the most appropriate next step in management?
- Prescribe full cycloplegic correction and re-evaluate in 6-8 weeks.
- Begin alternate-day patching of the dominant eye to treat presumed amblyopia.
- Proceed with bilateral medial rectus muscle recessions. (Correct answer)
- Observe the patient for spontaneous resolution until 6 months of age.
Correct answer: Proceed with bilateral medial rectus muscle recessions.
For infantile esotropia, which is a constant, large-angle deviation presenting before 6 months of age, surgical correction is the definitive treatment. While any significant refractive error should be corrected first, a hyperopia of +2.00 D is not considered high enough to be the primary cause of such a large deviation. Observation is not appropriate for a constant, large-angle strabismus. Early surgical alignment, typically between 6 and 24 months of age, offers the best chance for developing some level of binocular vision.
Question 2: Which of the following is the primary mechanism by which atropine penalization treats amblyopia?
- It paralyzes the extraocular muscles of the sound eye, preventing fixation.
- It causes a miotic pupil in the sound eye, degrading the retinal image through diffraction.
- It blurs near vision in the sound eye by paralyzing accommodation, forcing the use of the amblyopic eye. (Correct answer)
- It stimulates accommodation in the amblyopic eye, improving its focusing ability.
Correct answer: It blurs near vision in the sound eye by paralyzing accommodation, forcing the use of the amblyopic eye.
Atropine is a cycloplegic agent that paralyzes the ciliary muscle, thereby inhibiting accommodation. When instilled in the non-amblyopic (sound) eye, it causes significant blurring of near vision, making it difficult for the child to use that eye for near tasks. This 'penalizes' the sound eye and encourages the brain to use the amblyopic eye, thereby treating the amblyopia.
Question 3: A 6-year-old child presents with a complaint of an abnormal head posture, specifically a chin-up position. On examination, there is a marked limitation of elevation of the left eye when it is in the adducted position (looking up and to the right). Elevation in abduction is normal. What is the most likely diagnosis?
- Inferior oblique palsy
- Superior rectus palsy
- Brown syndrome (Correct answer)
- Duane retraction syndrome Type 2
Correct answer: Brown syndrome
Brown syndrome is characterized by a restrictive strabismus due to a tight or inelastic superior oblique tendon. The hallmark clinical sign is a limitation of elevation in adduction. Patients are often orthotropic in primary position but may adopt a chin-up head posture to maintain binocularity and avoid the field of restriction.
Question 4: A 5-year-old child undergoes vision screening and is found to have visual acuity of 20/80 in the right eye and 20/20 in the left eye. The child has no manifest strabismus. Cycloplegic refraction is +6.00 D sphere in the right eye and +1.50 D sphere in the left eye. What is the most likely cause of the decreased vision in the right eye?
- Strabismic amblyopia
- Deprivation amblyopia
- Meridional amblyopia
- Anisometropic amblyopia (Correct answer)
Correct answer: Anisometropic amblyopia
Anisometropic amblyopia occurs when there is a significant difference in refractive error between the two eyes (anisometropia). The brain favors the eye with the clearer image (the left eye in this case) and suppresses the input from the eye with the blurred image (the highly hyperopic right eye), leading to amblyopia. The +4.50 D difference between the eyes is a classic setup for this condition.
Question 5: An A-pattern esotropia is characterized by a horizontal deviation that is:
- Greater in downgaze than in upgaze.
- Greater in upgaze than in downgaze. (Correct answer)
- Equal in upgaze and downgaze but greater than in primary position.
- Associated with overaction of the inferior oblique muscles.
Correct answer: Greater in upgaze than in downgaze.
Alphabetical patterns describe a change in the horizontal deviation in vertical gaze. In an A-pattern, the eyes converge more in upgaze and diverge more in downgaze, resembling the shape of the letter 'A'. Therefore, an A-pattern esotropia will have a larger esotropia measurement in upgaze compared to downgaze.
Question 6: A 4-year-old boy presents with an intermittent exotropia that is well-controlled, occurring less than 50% of waking hours, primarily at distance when he is tired. His visual acuity is 20/20 in each eye, and stereopsis is excellent when his eyes are aligned. Refractive error is plano. Which of the following is the most appropriate initial management strategy?
- Immediate bilateral lateral rectus muscle recession.
- Prescription of over-minus lenses to stimulate accommodative convergence.
- Part-time occlusion of the dominant eye for 2-3 hours per day.
- Observation with follow-up in 6 months to monitor for progression. (Correct answer)
Correct answer: Observation with follow-up in 6 months to monitor for progression.
For a well-controlled intermittent exotropia in a young child with good visual acuity and stereopsis, observation is a very reasonable initial approach. Surgery is typically reserved for deviations that are poorly controlled (manifest >50% of the time), increasing in frequency, or associated with a loss of stereopsis or development of a suppression scotoma. While occlusion and over-minus lenses are sometimes used, observation is the most common and appropriate first step when control is good.
