MCQs for MRCOphth II
 

1. True statements about the circle of least confusion include:

a. it is the clearest image that a spherocylindrical lens can produce

b. it is located at a point corresponding to the spheroequivalent of a
    spherocylindrical lens

c. it is in the mid point of the Sturm's interval

d. it is increased if the distance between the two focal lines of a
    spherocylindrical lens is increased

e. the shape of the circle of least confusion is influenced by the shape of
    the spherocylindrical lens

Answer1.    a. T    b.T    c.T    d.T    e.TCircle of least confusionis the clearest image that an astigmatic eye or a spherocylindrical lens can produceis located at the point corresponding to the spherocylindrical lensis situated between the two focal lines of a spherocylindrical lens andtherefore mid-point of the Sturm's intervalis increased in size if the distance between the two focal lines of a spherocylindrical lens is increasedits shape is influenced by the shape of the spherocylindrical lens.The circle is circular if the lens is circular otherwise it will takes on the shape of the lens

2. The following are true:

a. simple myope can be corrected fully with minus sphere only

b. simple myopic astigmatism can be corrected fully with a minus sphere
    lens and a minus cylindrical lens

c. compound myopic astigmatism can be corrected fully with a plus
    sphere lens and a minus cylinder

d. simple hyperopic astigmatism occurs when one principal meridian is on
    the retina and the other is behind the retina

e. mixed astigmatism occurs when one principal meridian is on the retina
    and the other is behind the retina

Answer2.    a.T    b.F   c.F    d.T    e.TSimple myopia correctable with minus sphere lens onlySimple hyperopia correctable with plus sphere lens onlySimple myopic astigmatism correctable with plano sphere with minus cylinderSimple hyperopic astigmatism correctable with plano sphere with plus cylinder or plus sphere of same poweras minus cylinderCompound myopic astigmatism correctable with minus sphere with minus cylinderCompound hyperopic astigmatism correctable with plussphere with plus cylinder or plus sphere with minus cylinder of less magnitude than the sphereMixed astigmatism correctable with plus sphere with minus cylinder of greater magnitude than the sphere

3. True statements about ultrasound include:

a. the ultrasound used in diagnosis has a frequency of greater
    than 20 kHz

b. piezoelectric effect is used to emit ultrasound as well as analysing
    the echo

c. ultrasound is propagated as a transverse wave through a medium

d. ultrasound travels faster through vitreous than the lens

e. ultrasound with longer wavelength penetrates the tissue deeper
    than one with shorter wavelength

Answer3.    a.T    b.T    c.F    d.F    e.TUltrasound:acoustic wave with frequencies greater than 20 kHzthe transducer of the ultrasound contain a crystal whichemits the sound wave when excited by an electrical signal (piezoelectric effect), the sound emitted is reflected by the bodytissue which then acts on the crystal to produce an electrical signal(again a piezoelectric effect). The signal is analysed by a computer to produce an imageit is propagated a a longitudinal wave consisting of alternatingcompression and rarefraction of molecules as it travels through a mediumthe velocity is dependent on the medium and is faster in solidthan liquid mediumwith longer wavelength penetrates deeper into the tissue but has a poorer resolution than shorter wavelength

4. The following are true about Hess's test:

a. ocular dissociation is necessary

b. it can be used to calculate the amount of ocular deviation

c. a visual acuity of better than 6/12 is essential for the testing

d. the eye with restricted movement usually has a smaller field on the the
    Hess's chart

e. it can be used to test the field of binocular single vision.

Answer4.    a.T    b.T    c.T    d.T    e.FHess's test:used to measure and classifying ocular movement disorderscan be used to calculate the amount of ocular deviation because each small squares on the Hess's chart subtends5 degrees at a working distance of 50 cm foveal fixation isnecessary for the test and therefore a visual acuity of betterthan 6/12 is essentialrestricted eye movement gives rise to smaller field on the Hess's chart

5. True statements about dissociated vertical deviation include:

a. it is unilateral in 90% of the cases

b. it is associated with infantile esotropia

c. it is caused by inferior oblique overaction

d. it can be diagnosed with Bielschowsky darkening wedge test

e. it can be demonstrated with Bagolini filter bar

Answer5.    a.F    b.T    c.F    d.T    e.TDissociated vertical deviation:describe the elevation of the eye when the light entering it is reducedit is associated with infantile esotropia and is bilateral in the majorityof the cases though asymmetricalthe cause is unknownit can be diagnosed by cover test in which the occluded eye shows elevation but returns to its original position when the occluderis removed. Bielschowsky darkening wedge test and Bagolinifilter bar can also be used as they reduced the amount of light entering the eye

6. The following about Fresnel's prism are true:

a. its power is determined the thickness of the base

b. the visual acuity is affected by the power of the prism

c. it is normal fitted to the front of the spectacle

d. the maximum prismatic power than an adult can tolerate is usually
    around 15 dioptres

e. dividing the strength of the prism between the two eyes improves the
    comfort of the patient

Answer6.    a.F    b.T    c.F    d.F    e.TFresnel's prismis composed of contiguous small prisms which have thesame apex angle the power is determined by the apex anglethe visual acuity is affected by increased prismatic powerit can be used as an adhesive for the spectacle and is usuallyfitted on the posterior surfacethe maximum prismatic power than most adult can tolerate is 30 dioptrespatient's comfort can be improved if the prism strength (especially if high power) is divided between the two eyes.

7. Regarding the fusional reserves:

a. the horizontal fusional reserve is higher than the vertical fusional reserve

b. the positive fusional reserve is higher for distance than near

c. the positive fusional reserve is affected by the subject's
    accommodative reserve

d. the horizontal fusional reserve decreases with age

e. the vertical fusional reserve is decreased in patient with reduced
   accommodative reserve

Answer7.     a.T    b.F    c.T    d.T    e.FFusional reserve:refers to the amount of prism that needs to be placed in front of the eye to induce diplopiathe horizontal fusional reserve can be positive (the amount of base-out prism required to induce diplopia) or negative (the amount of base-in prism required to induce diplopia)the positive fusional reserve is affected by the accommodative reserve and therefore decreases with age. It is higher for near than for distancethe horizontal fusional reserve is higher than the vertical fusionalreserve. The vertical fusional reserve is measured by placing a base-up prism before one eye and base-down before theother until fusion is broken. Accommodative reserve is not involved in vertical fusional reserve

8. In the normal eye, resolution:

a. depends on cone separation

b. is 6/6 or better

c. depends on the size of the pupil

d. is about 10 minutes of arc

e. can be tested with the Sheridan-Gardner test

Answer8.     a.T    b.T    c.T    d.F    e.TResolution:is the least separation of two images so that they are seenas separate and is affected by the cone separationin normal subject is 6/6 or betteris dependent on the size of the pupil. A small pupil causes increased diffraction and therefore reduced resolution, pupil of about 2.5 mm is best for resolution above which optical aberration can affect the resolving poweris 1 minute of arc in normal subjectcan be tested with Sheridan-Gardner test which is a modified form of Snellen chart for testing children and the illiterate

9. The vernier acuity (hyperacuity):

a. is the ability of  the eye to detects  two images placed close together

b. depends on the separation of cone

c. in normal eye is less than 8 seconds of arc

d. requires the presence of binocular single vision

e. is used when performing applanation tonometer

Answer9.    a.F    b.F    c.T    d.F    e.TVernier acuity:is the determination of the eye to detect a break in a line andthis may be as little as 3 to 5 seconds of arcis not determined by cone separation because the normal acuityis only a fraction of the width of the cone, the mechanisminvolves in Vernier acuity is still unclear does notrequires binocular single vision is required in using optical instruments such as keratometer or applanation tonometer

10. True statements about diffraction include:

a. diffraction is increased when light passes through a smaller than a
    bigger aperture

b. diffraction is increased with shorter than longer light wavelength

c. diffraction which occurs when the light passes through the pupil is
    referred to as Fraunhofer diffraction

d. produces an Airy's disc which affects the resolving power of the eye

e. produces an Airy's disc which is bigger in a smaller than a bigger pupil

Answer10.    a.T    b.T    c.T    d.T    e.TDiffraction:occurs when a light passes through a gap or round objectproduces a change in the direction of the light waveis increased with smaller than bigger pupilis increased with longer wavelength than shorter wavelengths, and therefore red light diffracts more than blueFraunhofer diffraction refers to the production of an interference pattern by diffraction through a single slit (pupil) and this givesan Airy's discthe Airy's disc affects the resolving power of the eye. The minimumresolvable distance is about the radius of the Airy discthe Airy's disc is increased with a smaller pupil than a bigger pupil.The resolving power is therefore decreased with a smaller pupil

11. Spasm of accommodation:

a. can masquerade myopia

b. results in presbyopia

c. occurs more frequently in hypermetropia

d. causes convergence insufficiency

e. can be alleviated by miotics

Answer11.    a.F    b.F    c.T    d.F    e.FAccommodation spasm:can masquerade hypermetropia by the moving the far point forwarddoes not cause presbyopia which is caused by accommodationinsufficiencymore common in hypermetropia due to the attempted accommodative effort to bring the far point to he front accommodation is closely linked to convergence. In accommodation spasm, there is esotropia which is variablecan be alleviated by mydriatic

12. The following are true about schematic eye:

a. it contains six cardinal pints

b. the cornea has a higher refractive power than the lens

c. the cornea has a higher refractive index than the lens

d. the anterior focal point is longer than the posterior point

e. the posterior lens surface has a larger radius of curvature than the
    anterior lens surface

Answer12.    a.T    b.T    c.F    d.F    e.FSchematic eye:is a modified eye which is used to represent the optical system of the eyeit has a primary and secondary focal points, two principal points and twonodal points totalling six cardinal pointsthe cornea accounts for 2/3 of the total eye powerthe cornea has a higher refractive power than the lens but a lower refractive index than the lensthe anterior focal points is about 17.00 mm and that of the posterior focal point which is 22.60 mmthe posterior lens surface is more curved than the anterior lens surface and therefore smaller radius of curvature

13. Image distortion from a cylindrical lens can be minimized by:

a. decreasing the vertex distance

b. by reducing the cylinder power

c. using a toric contact lens

d. using plus cylinder lens

e. rotating the axis towards 90 or 180 degrees

Answer13.    at    b.T    c.T    d.F    e.TImage distortion from cylindrical lens can be reduced by:reducing the vertex distanceusing minus cylinder spectacle lensusing toric contact lensreducing the power of the cylinderrotating the axis towards 90 or 180 degrees

14. During streak retinoscopy, the following are true about the point of
       neutrality:

a. the reflex moves rapidly

b. the reflex becomes dimmer

c. moving towards the patient produces against movement in all meridians

d. the retinal and the peephole of the retinoscope forms the conjugate
    points

e. the retinoscopic refraction is complete

Answer14.    at    b.F    c.F    d.T    e.FAt the point of neutrality:the reflex moves rapidlythe reflex becomes brightermoving towards the patient produces with movement in all meridiansthe retina and the peephole of the retinoscope are conjugate in all meridiansthe working distance needs to be taken into account and therefore the refraction is not complete

15. Compared with soft contact lens, rigid gas permeable contact lens:

a. is suitable for intermittent wear

b. gives a better vision

c. has a greater diameter

d. is more resistant to wear and tear

e. is not suitable for keratoconus

Answer15.    a.F    b.T    c.F    d.T    e.F Hard contact lens:requires sometimes to get use to and is not suitablefor intermittent usegives a better visionhas a smaller diameter
 

16. Regarding accommodation:

a. half of the amplitude should always remain in reserve to avoid fatigue

b. the accommodative amplitude decreases by about 1.5D every 4
    years between the age of 40 and 48

c. accommodation decreases with age because the zonules become
    less elastic

d. movement of the cornea occurs during accommodation

e. accommodation can not occur in the absence of convergence

Answer16.    a.T       b.T    c.F    d.F    e.FAccommodation:occurs in response to blurred imagescan occur in the absence of convergencedecreases with age and is believed to be caused by the reduced deformity and elasticity of the lens proteinthe iris, len, vitreous and retina move during accommodationbut not the cornea

17. Stenopaeic slit:

a. is used to determine the power of the sphere

b. can determine the best vision in a certain axis

c. can help determine the position of an iridotomy in corneal
    scarring

d. can affect the visual acuity by the width due to the effect of
    diffraction

e. in a patient with astigmatism can improve the vision

Answer17.    a.F    b.T    c.T    d.T    e.TStenopaeic slit:can be used to determine subjective astigmatic refractive error, especially when the retinoscopic reflex is dim. The power can then be deducted by adding spherical power to the best visual acuitycan be used to locate the two meridians of astigmatismgives the best visual acuity when it is in the axis of the astigmatism and may be used to decide where iridotomy need to beperformed in corneal scarring to allow light passagecan be considered as an elongated pinhole and the narrower the slitwidth the more diffraction can occur which can affect the visual acuity

18. The following are true about Hertel's exophthalmometer:

a. the measurement may be affected by the presence of strabismus

b. the foot plate should rest on the lateral canthus rather than the
    orbital for accurate reading

c. patients of African origin has a higher normal reading than European

d. a difference in readings between the two eyes of up to 5 mm is
    normal in up to 50% of the population

e. can be used to monitor the progress of Grave's eye disease

Answer18.    .at    b.F    c.T    d.F    e.THertel's exophthalmometer:used to document and monitor the progress of proptosismeasure the distance from the orbital rim to the corneal apexand therefore the foot plates should rest on the orbital rimin the presence of strabismus, the corneal apex becomes deviated and reading can become inaccuratein Caucasian, the normal value is 15 to 17mm with a range of 11 to 21 mm; in African, this may range from 12 to 24 mma difference of 2 mm between the two eyes should be regarded as significant

19. The astronomical telecsope:

a. has an eye piece which has minus power

b. the separation of the eye piece and the objective piece is the sum
    of the focal lengths

c. the secondary focal point of the objective lens falls at the primary
    focal point of the eyepiece

d. the image is erect

e. the emergent rays are parallel

Answer19.    a.F    b.T    c.T    d.F    e.TAstronomical telescope:consists of two positive lenses (objective and eye pieces)the separation between the lenses are the sum of their focal lengthsthe image produced is invertedthe focal point of the objective lens conincides with the primaryfocal point of the eyepiecethe emergenct rays are parallel

20. Myopic shift occurs in:

a. keratoconus

b. spasm of the ciliary body

c. staphyloma

d. lens subluxation

e. brittle diabetes

Answer20.    a.T    b.T    c.T    d.T    e.TMyopic shift:occurs when the far point is moved forwardoccurs in keratoconus because the increased curvature of the cornea increase the refractive powerspasm of the ciliary body increases accommodation which bringsthe far point forwardstaphyloma occurs in conditions such as myopia or rheumatoid arthritis and moves the retina away from the far pointforward lens subluxation causes the far point to move forwardpoorly controlled diabetes mellitus can cause lens swelling resulting in increased refractive power

21. The following are true about magnifying glasses:

a. the angular magnification of a hand-held magnifier with a power
    of +20.00D is 5 X

b. Fixed stand magnifiers are designed to be used with a reading add

c. according to Kestenbaum's rule, a low vision patient with a Snellen
    acuity of 6/36 will required +6.00D add for reading

d. the visual field is increased by increasing the lens-eye position

e. the hand-held magnifier is normally placed 25 cm from the object.

Answer21.    a.T    b.T    c.T    d.F    e.TMagnifying glassesthe hand-held magnifier is normally placed 25 cm fromthe object and therefore the angular magnification is given by the formula D/4 where D is the dioptre power of the magnifier.Therefore for a +20.00D magnifier, the magnification is 5Xthe fixed stand magnifiers are designed so that thestand height is less than the principal focal length of the lens.This produces divergent light from the image. In a presbyopicpatient this should be used with reading glassesKestanbaum's rule is used to estimate the power of the additionneeded to read ordinary newsprint which is usuallyN7 or 8 in low vision patients. The power is obtained by divingthe denominator the Snellen visual acuity fraction by its numerator. Therefore, a patient with visual acuity of 6/36 will require an add of +6.00Dthe visual field and magnification are increased when the lens-eyeposition is reduced.

22. The following diseases are associated with myopia:

a. Stargardt's disease

b. Stickler's syndrome

c. juvenile retinoschisis

d. Marfan's syndrome

e. congenital glaucoma

Answer22.    a.F    b.T    c.F    d.T    e.TOther diseases associated with myopia include:Down's syndromeMarfan's syndromehomocystinuriaWeill-Marchesani's syndromeEhlers-Danlos syndromeStickler's syndromePierre-Robin's syndromePader-Will's syndromecongenital glaucoma

23. The range of stereoscopic vision as measured by the following tests
      are true:

a. 3000 to 60 seconds of arc with the Frisby's test

b. 3000 to 40 seconds of arc with the Titmus test

c. 480 to 15 seconds of arc with the TNO test

d. 1200 to 600 seconds of arc with the Lang stereostest

e. 3000 to 15 seconds with the synotophore

Answer23.    a. F    b.T    c.T    d.T    e.FStereoscopic visionis the awareness of disparity and therefore depth perceptionnormal is around 60 seconds of arccan be measured by various tests:Frisby's test        600 to 15 seconds of arcTitmus test        3000 to 45 seconds of arcTNO test            480 to 15 seconds of arcLang stereostest      1200 to 600 seconds of arcsynotophore        720 to 90 seconds of arc

24. With regard to the visual field:

a. lead poisoning causes cecocentral scotoma

b. tobacco amblyopia typically produces central scotoma

c. optic disc pit causes arcuate scotoma

d. retinoschisis causes binasal hemianopia

e. optic neuritis can cause homonymous hemianopia

Answer24.    a.T    b.F    c.T    d.T    e.FVisual fields:cecocentral scotoma is typically seen in toxic optic neuropathy such as tobacco-alcohol amblyopia, ethambutol and lead poisoningoptic disc pit can produce arcuate scotomabilateral retinoschisis in the temporal quadrants can cause binasal hemianopia homonymous hemianopia suggestsretrochiasmal lesion.

25. True statements about ametropia include:

a. myopia is commoner among school children than pre-school children

b. the incidence of hypermetrope increases with age

c. the antero-posterior diameter of the eye ball is increased in axial
   myopia

d. in refractive hypermetrope the refractive power of the eye is too
    strong

e. a hypermetropic patient is unable to focus on as a near a point as
    a myopic patient

Answer25.    a.T    b.T    c.T    d.F    e.TAmetropia:myopia is commoner among school children than pre-school childrenthe incidence of hypermetropia increases with agein axial myopia, the refractive power is normal bu the antero-posteriordiameter is increased. In refractive myopia, theantero-posterior diameter is normal but the refractive power is increasedin axial hypermetropia, the refractive power is normal but the antero-posterior diameter is increase. In refractive hypermetrope, the antero-posterior diameter is normal but the refractive power is decreasedin hypermetropia, the patient needs more accommodative power to bring a near object into focus and therefore he has a reduced amount of accommodative power to focuson as near a point as a myopic patient

26. True statements about the lens effectivity include:

a. it is equivalent to the back vertex power

b. it is affected the index of refraction of the lens material

c. in a hypermetropic patient wearing weak plus lenses, the effective
    power of the lens can be increased by moving the lens forward

d. a patient who is fully corrected with -10.00D spectacles at a vertex
    distance of 10 mm can be corrected a -9.00 D soft contact lens

e. a patient who is fully corrected with -10.00 D spectacles at a
    vertex distance of 10 mm will need a -15..00 D lens if the
    spectacles are now moved to 20 mm away from the eye.

Answer26.    a.F    b.F    c.T    d.T    e.FLens effectivity:refers to a change in the optical effect of a lens when its positionbefore the subject's eye is alteredis affected by the distance of the lens from the eyein a hypermetropia with weak plus lens, the image fallsbehind the eye. By moving the lens forward, the image isbrought forwards the lens effectivity is increased the formula below is used to calculate the lens effectivity:FX = F1/ (1-dF1)FX = power of lens needed at the lens position in dioptresF1= power of the original lens in dioptresd= distance moved in metres, it is negative when moved away from the eye and positive whenmoved towards the eyea patient who is fully corrected with -10.00D spectacles at a vertex distance of 10mm:the contact lens can be calculated with the above formula:FX = -10.00 / 1-(0.01)(-10.00)because the contact lens is apposed to the cornea thedistance moved is +0.01mFx = -9.10 D which is about -9.00Dthe lens required when the lens is moved to 20 mmFX= =10.00/1-(-0.01)(-10.00) because the lens is moved away from the eye the difference in distance is -0.01FX= -11.1D which is about 11.0D

27. The following are true when a patient changes from spectacle to contact
       lens:

a. more accommodation is required when a myope changes from
    spectacle to contact lenses

b. less accommodation is required when a hypermetrope changes from
    spectacles to contact lenses

c. a myope with esophoria at near will experienced increased esophoria
    when changes from spectacles to contact lens

d. a myope requires more fusional convergence when using spectacle
    than using contact lenses

e. contact lenses are better than spectacles for presbyopic myopia

Answer27.    a.T    b.T    c.T    d.F    e.FContact lenses vs spectacles:when a patient changes from spectacles to contact lenses thereis a change in the demands on accommodation and convergencea hyperope who wears glasses will need more accommodative effort per dioptre of accommodation than a myope who wearsglasses. When contact lenses are used, a hyperope needs to use less accommodation whereas a myope requires more accommodationa myope with esophoria will requires more accommodation and therfore more convergence when using contact lensesrather than glasses. This results in more esophoriaglasses for myope can be regarded as having a base-in prism andtherefore less fusional convergence is neededbecause contact lenses in myope requires more accommodationand convergence it can be precipitates problem for presbyope

28. The following are true about indirect ophthalmoscopy:

a. the aerial image of the retina is formed between the subject's eye and
    the condensing lens

b. the aerial image of the retina is an inverted real image

c. in an emmetrope, a 30D condensing lens produces a larger retinal
    images than a 20D lens

d. in an emmetrope, a 30D condensing lens gives a larger visual field
    than a 20D lens

e. for a given condensing lens, the aerial image of a hypermetropic retina
    is larger than a myope.

Answer28.    a.F    b.T    c.F    d.T    e.TIndirect ophthalmoscopy:the aerial image of the retina is an inverted real image which is situatedbetween the condensing lens and the examiner's eyethe stronger the condensing lens, the smaller the magnification of theretinal imagethe stronger the condensing lens, the larger the field of viewmyopic eye results in a lower magnification but a wider field of view than a hypermetropic eye

29. The following are true about ophthalmoscope:

a. the image is laterally transposed with the indirect ophthalmoscope

b. the teaching mirror on the indirect ophthalmoscope works on the
    principles of total internal reflection

c. the magnification of the retina with the direct ophthalmsscope is about
    15X

d. refractive error has a more significant effect with the direct
    ophthalmoscope

e. the field of view is larger with he indirect ophthalmoscope

Answer29.    a.T    b.T    c.T    d.T    e.Tthe image in indirect ophthalmoscope is vertically and horizontally transposedthe teaching mirror works on the principal of internal reflectionthe magnification with the direct ophthlamoscope is about 15Xthe magnification with a indirect ophthalmoscope using a 20D is about 3X.refractive error has a greater effect with direct ophthalmoscopethe field of view is larger with indirect than direct ophthalmoscope ( 6 degrees vs 25 degress)

30. With regard to Bagolini's glasses:

a. the test is only useful for adult

b. contain two lenses one with striation set at 90 degrees and the other
    at 180 degrees

c. amblyopia in one eye always result in perception of only one line

d. a cross is only seen in subjects with binocular single vision

e. can be used to test the presence of abnormal retinal correspondence
    when combined with cover / uncover testing

Answer30.    a.F    b.F    c.F    d.T    e.TBagolini's glassescontain two lenses with striation (optical principles similar to Maddox rods)one with striations at 45 degrees and the other at 135 degreesit can be used in children who can describe what they seea spotlight stimulus is used, an if there is a no suppression, the subject will see two diagonal lines crossing at above orbelow the light sourcebinocular single vision is needed for the perception of a crossamblyopia  depending on the severity will result in either absenceof one line (if dense) or part of the line (if mild)if a cross were seen when the cover / uncover test shows an ocular deviation, the subject has harmonious, abnormalretinal correspondence.