Strabismus (Types, Diagnosis, Treatment) MCQs

Ophthalmology · 33 free questions with answers & explanations.

1. A 3-year-old child is noted to have the right eye deviating inward. Cover test reveals that covering the right eye causes an outward movement of the left eye, and uncovering the right eye causes the right eye to move inward again. The child fixes with the left eye. This is best described as:
2. A 6-year-old hypermetropic child (+4.50 D in both eyes) develops esotropia that is fully corrected by wearing his spectacles. The AC/A ratio is normal. This is classified as:
3. A 5-year-old child has an exotropia with deviation of 30 prism diopters (PD) at near and 40 PD at distance. The increased deviation at distance is characteristic of which type of exotropia, and what does the distance-near disparity indicate?
4. A 4-year-old child is noted to have a hypertropia of the left eye that is greater when the chin is elevated and when the head tilts to the left. He holds his head tilted to the right and chin down. The most likely diagnosis is:
5. A 4-year-old child has right esotropia of 30 prism diopters for distance and near fixation. Cycloplegic refraction shows +4.0 D sphere bilaterally. With full refractive correction, the esotropia is fully eliminated. Which TYPE of esotropia is this, and what is the underlying mechanism?
6. A child has right superior oblique palsy (CN IV) confirmed by 3-step test. The head tilt is to the LEFT (away from affected eye). Which of the following best explains the pathophysiology of the head tilt in CN IV palsy?
7. In a child with right superior oblique palsy (CN IV palsy), the Parks-Bielschowsky three-step test will show which combination of findings?
8. Duane retraction syndrome type I is characterized by which specific pattern of eye movement abnormality?
9. In the management of accommodative esotropia with high AC/A ratio, the preferred optical correction approach is:
10. Brown's syndrome (superior oblique tendon sheath syndrome) shows a specific pattern on the three-step test for vertical diplopia. Which finding differentiates it from superior oblique palsy?
11. Duane's retraction syndrome Type I (most common type) results from which developmental anomaly?
12. In the Hirschberg corneal light reflex test, each millimeter of decentration of the corneal light reflex from the pupil centre corresponds to approximately how many prism diopters of deviation?
13. In Brown syndrome (superior oblique tendon sheath syndrome), the characteristic finding on forced duction test is:
14. In the management of infantile esotropia, the MOST critical determinant of sensory outcome (binocular single vision and stereopsis) is:
15. A patient has a large-angle esotropia and fusing none at distance. The 3-prism-dioptre (3Δ) base-out test for microtropia shows a movement suggesting the existence of which sensory anomaly?
16. In a 3-year-old child with constant left esotropia of 30 prism diopters and no refractive error, the Prism Adaptation Test (PAT) is performed before surgery. A child who shows full adaptation (manifest angle increases to 50 PD) benefits from surgery targeting the adapted angle because:
17. In the 4-diopter prism base-out test to detect microtropia (<10 PD), which response confirms the diagnosis of microtropia with identity?
18. In the Parks three-step test for diagnosing cyclovertical muscle palsy, a patient has: left hypertropia in primary position, worse on right gaze, and worse on left head tilt. The paretic muscle is:
19. In the surgical correction of a large-angle divergent strabismus (exotropia > 35 prism diopters), the preferred surgical approach is:
20. In a patient with left superior oblique palsy (CN IV palsy), the head tilt is typically to the right (away from the affected side). This compensatory head posture is assumed to:
21. The Parks three-step test is used to identify the paretic muscle in vertical strabismus. In a patient with right hypertropia that increases on left gaze and on head tilt to the right, which muscle is paretic?
22. A 6-year-old child presents with a head tilt to the left shoulder, chin down, and face turn to the right. Cover test reveals a right hypertropia that increases in left gaze and with right head tilt (Bielschowsky positive). The MOST likely diagnosis is:
23. A 5-year-old child with no glasses presents with esotropia measuring 30 prism dioptres (PD) at both distance and near. Cycloplegic refraction reveals +5.00 D hypermetropia bilaterally. After full refractive correction with spectacles, the esotropia reduces to 8 PD at near but 22 PD at distance. This is most consistent with:
24. In the Hirschberg corneal reflex test, the light reflex is centred in the right eye but displaced 2 mm nasally in the left eye. How much deviation and in which direction does the left eye have?
25. A 7-year-old girl has alternating exotropia with a deviation of 35 PD at distance and 20 PD at near. Stereopsis is reduced. She demonstrates the 'basic' type of intermittent exotropia (XT distance/near ratio close to 1). Before considering surgery, the most appropriate first-line non-surgical approach is:
26. In a patient with a right superior oblique (CN IV) palsy, which of the following Parks 3-step test findings would confirm the diagnosis?
27. In the cover-uncover test, movement of the covered eye as the cover is REMOVED indicates:
28. The Hirschberg test, used to estimate the angle of strabismus in a non-cooperative child, relies on which principle?
29. A 6-year-old child has a right esotropia of 30 PD at distance and near. Cycloplegic refraction reveals +4.50 D in both eyes. After full cycloplegic correction, the esotropia reduces to 10 PD. The residual deviation of 10 PD is non-accommodative. What type of esotropia is this?
30. A patient complains of diplopia that is worst when looking down and to the left. Bielschowsky's head tilt test is positive on tilting to the right shoulder. Parks three-step test identifies a right superior oblique palsy. What is the action of the superior oblique muscle in the primary position?
31. A child presents with an esotropia measuring 45 prism dioptres at distance and 20 prism dioptres at near. The near-distance disparity suggests which type?
32. Parks 3-step test identifies a paretic cyclovertical muscle. The three steps are: (1) hypertropia in primary position, (2) side of gaze increasing the deviation, (3) head tilt increasing the deviation. In a right hypertropia that increases in left gaze and on right head tilt, the paretic muscle is:
33. In accommodative esotropia managed with spectacle correction, a child wearing full cycloplegic refraction still shows residual esodeviation at near > distance. This suggests: