April 2011: C-15873 Paediatric Optometry Part 1

Detailed Answers
IMAGE A:
SPH CYL AXIS Prism VA BVD
R +5.00 ---- ---- ---- 6/6-2 12mm
L +3.00 ---- ---- ---- 6/6 12mm
C-15873 Paediatric Optometry Part 1
Professor Bruce Evans
April 2011
1. Which of the following is NOT an indication to fit contact lenses for the patient in Image A?
a. There will be reduced effects of aniseikonia from anisometropia
b. If there is strabismus when not wearing spectacles during sport
c. The patient does not wash their hands regularly e.g. meal times
d. Improved cosmetic appearance, confidence and social acceptance
The correct answer is C. Winn and colleagues demonstrated that, for all types of anisometropia,
aniseikonia is reduced with contact lens correction compared to spectacles. 1 Some children with
significant degrees of hypermetropia experience accommodative esotropia when their spectacles are
removed. In these cases, it is important to encourage refractive correction for as much of the waking
hours as possible and contact lenses can help achieve this for sport. Compared with spectacles,
contact lenses also improve children’s cosmetic appearance, confidence, and social acceptance. 2
This is particularly important because bullying can be a problem for spectacle wearers. 3 However,
contact lenses are not indicated for children who lack the necessary hygiene.
2. Which of the following is the MOST appropriate contact lens choice if the patient in image A
wants to wear them for gymnastics three times per week?
a. Silicone hydrogel continuous wear lenses
b. Rigid gas permeable lenses
c. Toric daily disposable soft lenses
d. Spherical daily disposable soft lenses

The correct answer is D. Spherical lenses (not toric) are appropriate for the prescription shown and
children adapt well to daily disposable lenses which have the advantage of not needing daily
cleaning. 4 Rigid gas permeable lenses are an option, but some children are discouraged by
discomfort during the early stages of adaptation. Continuous wear with silicone hydrogel lenses is
another option, but this modality is fitted less often to children because of the higher risk of
microbial keratitis.
3. When fitting contact lenses for the patient in Image A, which of the following statements is
TRUE?
a. They will accommodate more with spectacles compared to contact lenses
b. They will accommodate less with spectacles compared to contact lenses
c. A correction for back vertex distance is required for the left eye but not the right eye
d. Over-refraction will not be necessary after correction for back vertex distance
The correct answer is A. The ocular accommodation that is required through contact lenses is
different from that through spectacles. Spectacles induce less accommodation in myopes and more
accommodation in hyperopes than that exerted by an emmetrope, or the ametrope when wearing
contact lenses. A correction for back vertex distance is most important in the more hypermetropic
eye. But even if such a correction is made the patient should still be over-refracted to check the
optimal power for contact lenses.
IMAGE B:
SPH CYL AXIS Prism VA BVD
R +5.50 -0.25 180 ---- 6/6 12mm
L +5.00 ---- ---- ---- 6/6 12mm
4. What is the CORRECT description for the binocular vision anomaly shown in Image B?
a. Superior oblique palsy
b. Fully accommodative esotropia
c. Divergence weakness esotropia
d. Convergence weakness exotropia
The correct answer is B. The photographs show a right esotropia without spectacles, which is
straightened by refractive correction. This is a fully accommodative esotropia. 5
5. What is the CORRECT description for the refractive condition shown in Image B?
a. Anisometropic hypermetropia
b. Symmetrical hypermetropia
c. Pseudo over-accommodation

d. All the above
The correct answer is B. The prescription shows hypermetropia that is similar in each eye. This is
therefore symmetrical hypermetropia.
6. What is the MOST appropriate management option for the patient in Image B?
a. Use of spectacles only for near concentrated work
b. Full time wear of spectacles or contact lenses
c. Strabismus surgery
d. All the above
The correct answer is B. For accommodative esotropia, which is eliminated when the
hypermetropia is corrected, the only management is refractive correction. With this degree of
hypermetropia the patient is likely to need spectacles for distance vision as well as near, which will
help to prevent strabismus at distance. Strabismus surgery would be the wrong option. This is
because even if surgery could straighten the visual axes in childhood, then later when the
hypermetropia needed correction because accommodation reduces with age, refractive correction
could cause a secondary exotropia.
IMAGE C: Reproduced with kind permission from Professor David Thomson (Thomson Software
Solutions’ Test Chart 2000 Pro)
I II
III IV
7. A four-year-old patient attends for their first eye examination. Which of the charts shown in
Image C is the LEAST appropriate to use?
a. PANEL I
b. PANEL II
c. PANEL III
d. PANEL IV
The correct answer is D. an isolated optotype is the least appropriate target to use. One of the main
purposes of testing visual acuity in children is to detect strabismic amblyopia, which is most likely
to be detected if crowded rather than single optotypes are used. 5 Generally, it is better to use letters
that have been matched for legibility rather than pictures, but crowding is such an important factor
that it is probably preferable to use crowded pictures in preference to isolated letters.

8. Which one of the following is an advantage of the chart design shown in PANEL I of Image C?
a. The spacing of the optotypes and the lines follows a geometric progression
b. The same number of optotypes are presented on each line
c. There are equal crowding affects on each of the lines of acuity
d. All the above
The correct answer is D. Panel I shows a Bailey-Lovie design of letter chart. 6 Compared with
Snellen charts, the Bailey-Lovie design has several important advantages including the letter size
and inter-letter and inter-line spacing progress logarithmically from one line to the next and the
same number of optotypes are presented on each line. These features mean that there are similar
crowding effects and task difficulty on each line.
9. Which one of the following differences in chart design between the charts shown in PANEL I of
Image C and PANEL II of Image C is TRUE?
a. The optotypes in PANEL I are 5x4 in size whilst the optotypes in PANEL II are 5x5 in
size
b. The optotypes in PANEL I follow a logarithmic progression whilst the optotypes in PANEL
II follow an arithmetic progression
c. The optotypes in PANEL I have less crowding effects than the optotypes in PANEL II
d. The optotypes in PANEL I are suitable for children under the age of 4 years
The correct answer is A. The Bailey-Lovie chart uses letters that are slightly narrower than they are
tall (5x4) whereas the Kay pictures are 5x5 in dimensions, following the Sloan design. The
optotypes in both Panel I and Panel II follow a logarithmic progression and should induce similar
crowding effects although a casual inspection might suggest less inter-optotype spacing in panel I,
which could result in more crowding. It is easier to standardise the legibility of letters than pictures,
although pictures like the Kay ones or the Lea pictures (not show) may be necessary for some
children under the age of 4 years.
IMAGE D:
10. Which one of the following statements about the condition shown in Image D is FALSE?
a. This could be a congenital cataract
b. This could be retinoblastoma
c. This could be bilateral myopia
d. This could be a persistent pupillary hyperplastic vitreous
The correct answer is C. A white pupil (leukocoria) should always be taken seriously, although
sometimes a dilated fundoscopy shows this to be a false alarm. A true white pupil, like that shown
in the image, could have several causes, including congenital cataract, persistent pupillary
hyperplastic vitreous, retinal detachment, or of most concern retinoblastoma. Assuming that the
child is fixating the camera properly, it is not likely to be bilateral myopia.
11. What is the MOST appropriate management for the condition shown in Image D?
a. No management is required, review in 6 months
b. No management is required, review in 1 year
c. Routine referral to ophthalmology is required

d. Prompt referral to ophthalmology is required
The correct answer is D. Since there is a risk of retinoblastoma, a rapid referral is indicated. Even if
it is a less serious condition than retinoblastoma, like congenital cataract, then surgery as young as
possible will increase the probability of some usable acuity in this eye. 7
12. If the condition shown in Image D is corrected with phacoemulsification surgery, what is the
MOST likely management to be undertaken following surgery?
a. Refractive correction with occlusion of the operated eye
b. Refractive correction with occlusion of the good eye
c. Refractive correction without occlusion
d. No further management will be undertaken
The correct answer is B. If the white pupil is the result of a cataract then, even if early surgery takes
place, there is still likely to be dense deprivation amblyopia. If an intraocular implant is not used,
then the child will need contact lenses and occlusion. Even if an intraocular implant is used, then
there is still likely to be a residual refractive error so that the most likely outcome is refractive
correction and occlusion of the good eye.