1. Low Vision in Childhood
- How to apply neuroscience in optics -
Vassilis Kokotas, Optometrist, Ophth.D.c
37th Annual Meeting, 2011
Clinical Associate OEPF/COVD, U.S.A.
www.optometria.gr

2. Neonate or young baby
• Albinism
• Cerebral blindness
• Congenital cataract
• Congenital glaucoma
• Congenital idiopathic nystagmus
• Leber’s congenital amaurosis
• Macular coloboma
• Optic atrophy or hypoplasia
• Primary hyperplastic vitreous
• Retinoblastoma
• Retinopathy of prematurity

3. Childhood
• Best’s disease or vitelliform dystrophy
• Cone dystrophy
• Optic atrophy
• Retinitis pigmentosa
• Stargardt’s disease
• X-linked retinoschisis

4. Prognosis and rehabilitation
Pathology Visual Prognosis Visual Field Defects Visual Aids
(LogMAR)
Leber’s amaurosis LP – 1.0 Complete loss Vision substitution
Optic atrophy Variable. HM – 0.3 Paracentral scotomas Good with LVA
Optic disc hypoplasia Variable. Good or poor Variable Good with LVA
Cerebral blindness Variable, poor Difficult to test Poor with LVA. Enviromental
modifications
Delayed visual development Often normal Normal Good with LVA and/ or training
Albinism 1.0 – 0.5 Usually normal Good with LVA (distance)
Stargardt’s disease 50% > 0.1 / 50% < 0.1 Central scotoma Good with LVA
Cone dystrophy 1.0 – 0.6 Central scotoma Good with filters (red tint)
Best’s disease 1.0 Normal – Central scotoma Variable with LVA
Retinitis pigmentosa 1.3 - NLP Peripheral constriction and/ Good with LVA and CCTV
or central defect
X-linked retinoschisis 1.3 – 0.8 Peripheral and central Good with LVA
scotomas
A.J. Jackson, J.S. Wolffsohn (2007)

5. Low Vision Aids
Kids tend to reduce distance in order to gain magnification. But as they grow
older and accommodation lags they need to compensate with low vision aids.
Aphacic children need to be introduced to magnification as soon as possible.
Usually, they require higher amounts of magnification.
Children accept low vision aids and other visual modifications easier than
adults. They don’t experience emotions of loss and we meet less denial.
What looks a technological challenge for you, for kids is just a game.

6. Low Vision Aids
Eye – hand coordination is a very important factor that has to be developed
early with low to moderate magnification (table magnifiers, stand magnifiers,
magnifying rulers, etc).
Later, when head and ocular motor control is fine tuned magnifying glasses
can be used (monocular, prismatic binocular, special bifocals, etc).

7. Low Vision Aids
The use of hand held magnifiers can usually be incorporated for daily activities
when school starts. Combination with eyeglasses can provide patient with
higher magnificactions (with or without illumination, etc).
Telescopic systems can be used in a classroom environment too, although
hardly accepted due to aesthetic reasons (monocular, binocular, fixed,
removable, etc).

8. Low Vision Aids
CCTV and other electronic magnifiers can be used when good eye – hand
coordination has been established, although they are more necessary in
school years (colored, contrast enhancement, portable, etc).
New devices and software allow easy modification of size and spacing of
letters or even text to speech functions (e – readers, tablets, etc).

9. Definition of Vision
Clinicians experience the visual
process (apart from their own
vision) through testing and
therapy, thus each one creates
his/ her own model of vision.
“Vision is the ability of the organism
to derive meaning and direct
action, as triggered by light.”

10. Optics of our visual system
A good cell phone camera
can provide resolution up
to 5 Mpixel.
How many Mpixels is the
human eye?
Only 1 Mpixel…!!!

11. Multi-tasking,
simultaneous,
exchanging, parallel
processing systems.
Enriched by multi-sensory perception

12. Efferent pathway
represents about
8% of the optic
nerve. This
affects almost
90% of the flow
back to the brain.
Cortical feedback
to LGN may have
a role in
orientation tuning,
increasing
responses and
enhancing
contrast gain.
Enriched by efferent neural information

13. Window of attention & eye movements

14. The harder the task, the more central your window of
attention is and the more periphery is suppressed.
Window of attention & eye movements

15. Window of attention & eye movements

16. Enhancement
Optometric Vision Training
-Peripheral awareness
-Ocular motor dysfunctions
-Eye-hand coordination

17. Enhancement
Optometric Vision Training
-Binocular dysfunctions
-Accommodative dysfunctions
-Figure/ Ground
- Discrimination

18. Enhancement
Visual Imagery/ Visualization
Training
-Visual memory
-Visual attention
-Spatial perception

19. References
• A.J. Jackson, J.S. Wolffsohn. Low vision manual. Butterworth – Heinemann, 2007.
• Worgotter F, Nelle E, Li B, Funke J. The influence of corticofugal feedback on the temporal structure of
visual response of cat thalamic relay cell. J. Physiol. 1998;509:797-815.
• R.C. Peterson, J.S. Wolffsohn, M. Rubinstein, J. Lowe. Benefits of electronic vision enhancement
systems (EVES) for the visually impaired. Br. J. Ophthalmol. 2003;136:1129-1135.
• B.P. Rosenthal, R.G. Cole. Functional assessment of low vision. Mosby, 1996.
• Przybyszewski AW, Gaska JP, Foote W, Pollen DA. Striate cortex increases contrast gain of macaque
LGN neurons. Vis. Neurosci. 2000;17:485-494
• S.L. Macknik, S. Martinez-Conde. Sleights of mind. Henry Holt & Company, 2010.
• A. Robinson. Cunningham’s textbook of anatomy. Oxford University Press, 1931.
• D.N. Spinelli, K.H. Pribram, M. Weingarten. Centrifugal optic nerve responses evoked by auditory and
somatic stimulation. Exp. Neurol. 1965;12:303-319.
• C. Dickinson. Low vision. Principles and practice. Butterworth – Heinemann, 1998.
• W.V. Padula. Neuro-optometric rehabilitation. Optometric Extension Program Foundation, 1996.
• B. Silverstone, M.A. Lang, B. Rosenthal, E.E. Faye. The lighthouse handbook on vision impairment and
vision rahabilitation. Oxford University Press, 2000.
• E.B. Forrest. Visual imagery: An optometric approach. Optometric Extension Program Foundation, 1981.

20. Thank you!
E-mail: info@optometria.gr
Site: www.optometria.gr
37th Annual Meeting, 2011