KMU Past Paper Practice

Question:

A 3-year-old child is brought because the parents suspect an eye deviation, but the child is unable to cooperate with formal cover testing. A torchlight is directed toward both eyes and the corneal light reflections are found to be asymmetrical. What is the main value of this finding?

Correct Answer:
It provides a rapid estimate of manifest ocular misalignment

Explanation: The Hirschberg corneal light-reflex test is particularly useful in young children because asymmetric reflections provide a quick estimate of manifest strabismus when formal measurements are difficult.

Question:

An infant develops a large constant inward deviation during the first few months of life. Ocular movements are full, and appropriate refractive correction does not abolish the deviation. Which diagnosis best fits this pattern?

Correct Answer:
Infantile esotropia

Explanation: A large constant esotropia beginning in early infancy with full motility and little dependence on accommodation is characteristic of infantile esotropia.

Question:

A 6-year-old child has a persistent inward deviation associated with markedly reduced vision in one eye. Refraction does not explain the deviation, and ocular examination reveals a structural cause of poor vision. What should be a central part of management?

Correct Answer:
Identify and treat the ocular cause of visual impairment

Explanation: Sensory strabismus results from failure of binocular fusion due to poor vision; therefore, the underlying ocular disorder and visual potential must be addressed before alignment alone.

Question:

A 12-year-old child with intermittent exotropia is examined while fixing both a distant target and a near target. The ophthalmologist measures the deviation at both distances. What is the main reason for doing this?

Correct Answer:
To determine whether the size of deviation changes with fixation distance

Explanation: Comparing near and distance deviations helps characterize exotropia because its magnitude and binocular control may differ according to fixation distance.

Question:

A child with intermittent exotropia has been followed for one year. The deviation is now present for longer periods, control is deteriorating, and stereopsis is becoming poorer despite appropriate optical correction. Which management principle is most appropriate?

Correct Answer:
Consider strabismus surgery because binocular control is deteriorating

Explanation: Increasing frequency of exotropia, worsening control and declining stereopsis indicate loss of binocular stability and support consideration of surgical alignment.

Question:

A 5-year-old child with unilateral squint has significantly poorer visual acuity in the deviating eye. The examiner performs a detailed anterior segment and fundus examination. What is the most important reason for this step?

Correct Answer:
To exclude ocular pathology causing sensory strabismus

Explanation: Reduced vision may be the cause rather than merely the consequence of strabismus, so ocular examination must exclude structural disease responsible for loss of fusion.

Question:

A child with a treated squint has equal visual acuity in both eyes. The ophthalmologist next assesses stereopsis. What additional information does this test mainly provide?

Correct Answer:
Quality of binocular visual function

Explanation: Stereopsis reflects coordinated binocular vision and therefore helps assess the functional effect of squint beyond monocular visual acuity alone.

Question:

A 36-year-old patient develops an acquired incomitant squint and adopts a persistent abnormal head position while walking. Visual acuity is normal in both eyes. Why can this posture reduce symptoms?

Correct Answer:
It places the eyes in a gaze position where image separation is smaller

Explanation: Patients with incomitant strabismus may adopt a compensatory head posture that keeps gaze away from the position producing maximal ocular misalignment and diplopia.

Question:

A patient develops binocular diplopia, proptosis and restricted ocular movement. The movement pattern does not correspond to one ocular motor nerve. Which management approach is most appropriate?

Correct Answer:
Evaluate and treat an underlying orbital restrictive process

Explanation: Proptosis plus mechanically restricted motility suggests orbital disease; management must address the underlying restrictive process rather than treating diplopia alone.

Question:

A patient has a complete third cranial nerve palsy. The affected eye rests outward and downward, but some abduction remains possible. Which intact extraocular muscle mainly accounts for the outward component of the eye position?

Correct Answer:
Lateral rectus

Explanation: The lateral rectus is supplied by CN VI and remains functional in isolated CN III palsy, so its unopposed abduction contributes to the characteristic outward position.

Question:

A 58-year-old patient presents with ophthalmoplegia and complete drooping of the upper eyelid due to third cranial nerve dysfunction. Weakness of which muscle is directly responsible for the eyelid finding?

Correct Answer:
Levator palpebrae superioris

Explanation: CN III supplies levator palpebrae superioris; loss of its motor supply produces the marked ptosis seen in a complete third nerve palsy.

Question:

A patient with third cranial nerve palsy has a dilated pupil with poor reaction to light. Which functional pathway has been disrupted to produce this finding?

Correct Answer:
Parasympathetic pathway to the pupillary constrictor

Explanation: Parasympathetic fibers traveling with CN III supply the pupillary constrictor pathway; their dysfunction causes mydriasis and impaired light reaction.

Question:

A young man develops an isolated trochlear nerve palsy after a significant head injury. Which anatomical feature helps explain the vulnerability of this nerve to trauma?

Correct Answer:
Its long intracranial course

Explanation: The trochlear nerve has a long intracranial course and is therefore particularly susceptible to injury during significant head trauma.

Question:

A 35-year-old patient develops troublesome vertical diplopia after an intercurrent illness. Old photographs show a longstanding mild head tilt, but the patient previously had no diplopia. Examination now demonstrates a unilateral superior oblique weakness. Which explanation is most likely?

Correct Answer:
Decompensated congenital fourth nerve palsy

Explanation: A congenital fourth nerve palsy can remain compensated for years; longstanding head tilt on old photographs supports a pre-existing palsy that has later decompensated.

Question:

A patient with trochlear nerve palsy describes one image as tilted relative to the other. Loss of which normal action of the affected muscle best explains this torsional component of diplopia?

Correct Answer:
Intorsion

Explanation: The superior oblique contributes to intorsion; loss of this action produces torsional misalignment so the two images may appear tilted relative to each other.

Question:

A patient with right sixth cranial nerve palsy turns the face toward the right while viewing distant objects. What is the main purpose of this compensatory posture?

Correct Answer:
To reduce the need to look into the weak lateral rectus field

Explanation: Turning the face toward the affected side allows the eyes to remain relatively away from the direction requiring maximal abduction, thereby reducing diplopia.

Question:

A 64-year-old patient with an isolated sixth cranial nerve palsy reports that horizontal diplopia is substantially more troublesome when looking at distant road signs than while reading. Which physiological requirement best explains this pattern?

Correct Answer:
Divergence is more important for distant fixation

Explanation: Sixth nerve palsy impairs abduction, so the patient’s difficulty becomes more evident during distant fixation when relative divergence of the visual axes is required.

Question:

A previously healthy 15-year-old develops a new unilateral abduction deficit and horizontal diplopia. There is no history of diabetes or hypertension and no longstanding childhood squint. What is the most appropriate clinical principle?

Correct Answer:
Evaluate for an underlying neurological or intracranial cause

Explanation: A new sixth nerve palsy in a young patient should not be assumed to be benign microvascular disease; the clinical context warrants investigation for neurological causes.

Question:

During routine assessment, a student’s eyes appear aligned while both are open. When binocular fusion is interrupted, one eye drifts from alignment but resumes its normal position when fusion is restored. Which physiological mechanism normally keeps this deviation hidden?

Correct Answer:
Binocular fusion

Explanation: A heterophoria is a latent tendency to deviate that remains controlled while binocular fusion is active and becomes visible only when fusion is interrupted.

Question:

The parents of a child with strabismus ask whether eye exercises should be prescribed routinely instead of defining the type of deviation. Which principle regarding orthoptic treatment is most appropriate?

Correct Answer:
It is useful in selected disorders of binocular control rather than every squint

Explanation: Orthoptic therapy has a selective role in appropriate binocular-control disorders; it does not replace accurate diagnosis, refractive correction or treatment of underlying disease.