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Thread: A 22-year-old woman has noticed blurry vision. On examination her pupils are equal in size.

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    Arrow Is the onset of presbyopia depends on amplitude of accommodation?

    Presbyopia - MCQS

    Question: 1

    1. The onset of presbyopia depends on:

    a. the size of the pupil

    b. task required

    c. sex of the patients

    d. the refractive state of the patients

    e. amplitude of accommodation


    Answer:

    [HIDE]
    A. True
    B. True
    C. False
    D. True
    E. True
    [/HIDE]
    -----------------------------------

    Reference:

    Presbyopia

    During middle age people experience blurred vision when reading or looking at objects close up.

    Presbyopia is a natural part of the ageing process resulting in a gradual decline in the ability to focus on close objects or to see small print. Presbyopia is due to the lens losing its flexibility, making it more difficult to focus on objects up close. This condition becomes evident in almost all people over the age of 45.

    Causes of Presbyopia

    In order for the eye to focus on an object, the lens changes shape depending on the distance of the object. For the eye to focus on an object up close, this will require the ciliary muscle (which controls the shape of the lens) to contract inorder for the lens to thicken and increase the focusing power to the eye. To focus on something at a distance the ciliary muscle relaxes, which causes the lens to flatten.

    With the natural ageing process the eye's lens stiffens, and it is less able to focus on objects up close. These changes occur within the proteins in the lens, causing the lens to become harder and less elastic. Age-related changes also take place in the ciliary muscle surrounding the lens.

    Diagnosis of Presbyopia

    As presbyopia comes on gradually with age (usually in the 40's onwards) most people don't notice small vision changes and delay seeking professional help until the focusing problems interfere with daily life. Many optometrists joke that patients seek help only when their arms become "too short," as they are unable to hold printed pages far enough away from them inorder to see clearly.

    Presbyopia will be diagnosed by an optometrist, ophthalmologist or eye care professional who will test your vision

    If the diagnosis is presbyopia, a test will be undertaken to determine the extent of the focusing problem and the appropriate lens prescription.

    Treatments for Presbyopia

    The most common form of treatment for presbyopia is with prescription or reading glasses. Long sighted glasses wearers with presbyopia will need to use bifocals. These are lenses for both distance vision and for observing objects close up.

    Bifocal contact lenses are another option which provide the convenience of contact lenses and the ability to see close up as well as far away.

    Another popular alernative is monovision where one eye is used for viewing in the distance, and the other eye for viewing things up close.

    It is also possible to postpone or slow down the hardening of the lens through good nutrition, aerobic exercise and a healthy lifestyle.

    Refractive surgery for presbyopia is an option that many people enquire about, however many procedures are in investigational stages. There is a lot of disagreement about the causes of presbyopia, and so many of the new procedures have little incommon with each other as they treat different possible causes.

    Procedures such as monovision LASIK eye surgery works well for many patients regardless of the cause of presbyopia.

    -----------------

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    Presbyopia - MCQS

    Question: 2

    Presbyopia occurs as a result of:

    a. loss of elasticity of the sclera

    b. sclerosis the lens fibres

    c. reduced elasticity of the lens capsule

    d. reduced anterior movement of the lens

    e. reduced contraction of the ciliary muscle


    Answer:

    [HIDE]
    A. False
    B. True
    C. True
    D. False
    E. True
    [/HIDE]
    -----------------------------------

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    Presbyopia - MCQS

    Question: 3

    The following are true about accommodation:

    a. it decreases with age

    b. in order to focus an object at a distance of 25cm, an emmetropic eye needs to use 4D of accommodation

    c. in order to focus an object at a distance of 25cm, an eye with -3.00D needs 2D of accommodation

    d. in order to focus an object at a distance of 25cm, an eye with +2.00D needs 6D of accommodation

    e. for comfortable near vision one-third of the accommodation should be kept in reserve


    Answer:

    [HIDE]
    A. True
    B. True
    C. False
    D. True
    E. True
    [/HIDE]
    -----------------------------------

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    Presbyopia - MCQS

    Question: 3

    The following are true about an emmetropic patient has an amplitude
    of accommodation of 6D.


    a. the near point is 33 cm

    b. in order to achieve comfortable reading he will need to keep 2D of
    his accommodation in reserve

    c. if the patient is emmetropic, he will require glasses for comfortable
    reading at 25cm

    d. if the patient is myopic, he will require glasses for comfortable reading
    at 25cm

    e. if the patient is hypermetropic, he will require glasses for comfortable
    reading at 25cm


    Answer:

    [HIDE]
    A. False
    B. True
    C. False
    D. Falsef
    E. True
    [/HIDE]
    -----------------------------------

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    Default A 22-year-old woman has noticed blurry vision. On examination her pupils are equal in size.

    Cranial Nerves- MCQs


    Question 1


    A 22-year-old woman has noticed blurry vision. On examination her pupils are equal in size. As the flashlight is shined from eye to eye, you see the pupil dilate when you shine the flashlight in the right eye. What is the most likely explanation for her blurry vision?


    A. She has myopia and needs glasses.
    B. She has a sympathetic denervation (Horner's syndrome) of her left eye.
    C. She has anisocoria
    D. She has a right optic nerve lesion.
    E. She has compression of the right oculomotor nerve.



    Answer:

    [HIDE]


    The correct answer is D.

    The patient has a relative afferent pupillary defect of the right eye. Because there is a lesion of the optic nerve in the affected eye less light is perceived therefore the pupil will dilate when the flashlight swings over to the involved eye. Deceased visual acuity is seen with lesions of the optic nerve.



    [/HIDE]

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    Cranial Nerves- MCQs


    Question 2


    A 12-year-old boy complains of side by side or horizontal double vision when looking to the left. When he looks to the left and the left eye is covered, the most peripheral image disappears. The cause of his diplopia is paralysis of which one of the following cranial nerves?


    A. Right 6th nerve.
    B. Left 6th nerve.
    C. Right 3rd nerve.
    D. Left 3rd nerve.
    E. Right 4th nerve.



    Answer:

    [HIDE]


    The correct answer is B.

    The eye cannot abduct so there is double vision when looking to the left. The false image is always the most peripheral image and is always from the abnormal eye. Covering the left eye eliminates the false or ghost image so it is the abnormal eye.


    [/HIDE]

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    Cranial Nerves- MCQs


    Question 3


    A 55-year-old diabetic male complains of double vision. On examination of his extraocular movements, you notice limited adduction, elevation, and depression of his right eye. The pupils are equal and reactive. The patient most likely has a lesion of which one of the following cranial nerves?


    A. Left 6th nerve.
    B. Right 6th nerve.
    C. Left 3rd nerve.
    D. Right 3rd nerve.
    E. Left 4th nerve.




    Answer:

    [HIDE]


    The correct answer is D.

    The right eye has limited range of motion for the muscles innervated by the 3rd nerve. The question is you mind should be why isn't the right pupil dilated as well? If the 3rd nerve lesion was caused by compression of the nerve then the parasympathetic fibers which travel on the outer side of the 3rd nerve are involved and there is always a dilated unreactive pupil associated with the palsy. Diabetes can cause a pupillary sparing 3rd nerve palsy because of infarction of an endoneurial vessel which does not affect the parasympathetic fibers on the outside of the nerve.


    [/HIDE]

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    Default

    Cranial Nerves- MCQs


    Question 4


    The patient's eyes do not turn in the opposite direction of head movement. Which one of the supranuclear gaze systems is affected?

    A. Frontal gaze center.
    B. Parietal-occipital gaze center.
    C. Vestibuloocular system.
    D. Occipital mesencephalic pathways.




    Answer:

    [HIDE]

    The correct answer is C.

    The vestibuloocular system keeps an image steady on the fovea during head movements.


    [/HIDE]

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    Cranial Nerves- MCQs


    Question 5


    The patient has difficulty with large amplitude eye movements needed to fix on a new target. Which one of the supranuclear gaze systems is affected?



    A. Frontal gaze center.
    B. Parietal-occipital gaze center.
    C. Vestibuloocular system.
    D. Occipital mesencephalic pathways.



    Answer:

    [HIDE]

    The correct answer is A.

    The frontal gaze center is for saccadic eye movements which are rapid eye movements used to bring new objects being viewed on to the fovea.

    [/HIDE]

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    Cranial Nerves- MCQs


    Question 6


    The patient has difficulty seeing objects 6 inches in front of nose. Which one of the supranuclear gaze systems is affected?



    A. Frontal gaze center.
    B. Parietal-occipital gaze center.
    C. Vestibuloocular system.
    D. Occipital mesencephalic pathways.





    Answer:

    [HIDE]

    The correct answer is D.

    The occipital mesencephalic pathways are important for vergence which is keeping an image on the fovea when the viewed object is moved near to the face.

    [/HIDE]

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