0. Anatomy and Function of the Eye and Ocular Disorders Part II
Developed by SKI-HI Institute Utah State University Winter 2011
For use in Training

1. The Human Eye retina macula fovea optic nerve optic disc choroid
vitreous humor
La Clinica Oculistica Virtuale

2. Choroid If deprived of its blood supply for
more than a few minutes, will die
Cannot be regenerated
Nourished by blood vessels that
enter eye near optic nerve and which spread across surface of
retina
Choroid supplies retina with
nourishment

3. Rod and Cone Cells Color vision Detail, reading vision Rods
More in the peripheral retina
Detect motion
Function at low luminance level…night vision
Gross forms and shadow
Cones
Color vision
Detail, reading vision 3 3

4. Night Vision and Night Blindness 4 4

5. Prematurity and ROP Factors causing ROP are: excessive
oxygen, prematurity, infection,
excessive exposure to light
Babies born today are more
premature and lower in weight
Aggressively treated and have a perilous neonatal period
full of numerous life sustaining procedures
Medical technology has increased survival, but not the
chances of ROP occurring
ROP a major cause of infant blindness in developed
countries
National Eye Institute, National Institutes of Health

6. The Disease Process in ROP
Baby born early, retina has not
vascularized yet—blood vessels
grow from optic nerve head
to outer reaches of retina
Growth stops for a while
Then oxygen causes them to
grow wildly, tangle and grow
into vitreous, not to edges
Vessels hemorrhage, scar tissue
forms and vitreous contracts,
damaging retina and causing
detachments
National Eye Institute, National Institutes of Health

7. Stages of ROP 1 2 3 4 5 Stage Description of Retina No abnormality
No abnormality 1
Minor changes in periphery of retina; some irregular
blood vessels; see white band between area of retina with and area without blood vessels 2
Same characteristics as stage 1; now area without
blood vessels looks silvery gray and opaque; band has
Increased in height and width 3
Band now forms a thick ridge; lots of blood vessels near
the ridge and spreading into vitreous 4
Peripheral retina starts to pull away, moderate detachment 5
Advanced or total retinal detachment

8. Zones of ROP Described as if retina were the face of a clock
ROP in zone 1 more serious
as it may involve the macula,
affecting central or reading
vision
ROP in zone 1, at 1-2 o’clock
position, retinal changes don’t
involve the macula; are
further away

9. Treatment of ROP Observation/Monitoring
Most babies with ROP get better on their own
For most, disease can get worse fast and without treatment,
half will end up blind
Surgical Treatments
May be used alone or in combination
laser photocoagulation
cryotherapy-freezing
surgical repair
Length of time between detachment
and surgery is crucial to restoring
vision

10. Vision Impairment in ROP
Baby’s vision can vary from near normal to total blindness, depending on how changes had progressed
prior to diagnosis and treatment
ROP sometimes spontaneously regresses or cures itself and retina returns to near normal; rarely happens after stage 3
Children with ROP may later develop myopia or near sightedness, strabismus, cataracts, nystagmus, astigmatism, microphthalmia, or blue-yellow color deficits
In the adult years, may develop further myopia,
cataracts, closed-angle glaucoma or further detachment

11. Other Disabilities and ROP
70 % of infants born under a pound in weight and
3 months premature have additional disabilities such as:
Brain damage
Cerebral Palsy
Seizures
Hearing Loss
Learning disabilities
Cortical/Cerebral
Visual Impairment
Sensory Issues

12. Other Retinal Conditions
Macular Degeneration
Retinitis Pigmentosa
Ushers
Leber’s Amaurosis
Coloboma
CHARGE
Rubella
CMV 12

13. Retinoblastoma A slow growing malignant tumor that arises from retina
Hereditary or non-hereditary; one or both eyes
Both types gradually fill the eye then extend through the optic nerve to the brain or into sclera and surrounding tissue
Pupil appears white or glows,
strabismus present, eye inflamed
Discovered before age of three;
diagnosed by ultra-sound, MRI, CT
Treatment: may remove the eye; in some cases chemo
or radiation is used; high survival rate
Cataracts may result from treatment

14. Traumatic Retinal Detachment/Hemorrhage
Shaken Baby Syndrome (SBS)
Infant forcefully shaken
Retina detaches as result of direct traumatic injury or secondary complication of bleeding in the eye
Visual impairment due to retinal detachment, optic atrophy or damage to visual pathways in the brain
Head Injury
Similar destruction as SBS, most commonly occurring
in car accident

15. Other Infections Toxoplasmosis
Infection of eye that is the result of maternal exposure
during pregnancy to a parasite in cat feces
Can affect the brain as well as the eyes
Toxocara
Acute inflammatory response inside eye in response to a
parasite in dog feces
Causes cataracts, inflammation of vitreous
Herpes
Blood-born viral infection transmitted during pregnancy or delivery that can cause severe damage to brain and
retina

16. Loss of Color Vision More common in males than females
Three types of color photoreceptors in the retina—red, green, and blue cones; defect may lie in ay of these
Most common: an inability to distinguish reds and greens
Present in both eyes and remains constant over time
Occasionally accompanies retinal disease or exposure to toxic materials that damage cones
No known treatment

17. Loss of Color Vision Simulated
Normal
Red
Blue
(rare)
Green
graphics.cornell.edu

18. Myopia or near sightedness
Normal vision
Myopia or near sightedness
eyeatlas.com 19

19. Hyperopia or far sightedness
Astigmatism
eyeatlas.com 20

20. Glasses Can’t Fix Every Eye Problem!
Dr. Lea Hyvärinen, Helsinki, Finland 21

21. Eyes in Constant Motion
Human eye is in constant state of vibration, oscillating back and forth at rate of 60 per second
Serve to refresh the image cast on rods and cones at back of eye
Without these microsaccades,
staring fixedly causes distortions
Rods and cones respond best to
changes in color and luminance
These saccades are so small they are imperceptible to others
In many children with poor vision, these
microsaccades are exaggerated, so
we see them as nystagmus
Saccades of eye looking
at a photo of a face
Artlex.com

22. Nystagmus Involuntary rhythmic, jerky eye movement
Vertical, horizontal or rotary
May decrease with age
Slightly blurs vision, central vision decreased
May hold objects closer to eyes
May turn head slightly to use null point
Increases with fatigue, stress, excitement
Dr. Lea Hyvärinen, Helsinki, Finland 23

23. Difficulties with Saccades When Reading
Children with conditions such as nystagmus or strabismus
may have inefficient reading saccades
Eye movements may be bigger; less room for error
They may struggle and lose their place
Enlarging the print may help
Using a finger or line marker to keep their place may help
Presenting print on computer line by line or in shorter lines
Use of finger to keep place Use of paper as line marker
to keep place

24. Random or Roving Eye Movements
Sign of poor acuity; takes good acuity to fixate
As if eyes are trying to find a target, but can’t quite focus on it well

25. Medications That Cause Double or Blurred Vision
May include antidepressants, antidiabetic drugs,
barbiturates, cortisones, sedatives, and tranquilizers
Contact physician if any changes are noticed when using
such drugs
The side effects can interfere with vision
Many children with multiple disabilities are on seizure medications which can cause visual side effects (blurring, less alert, double vision).
Great handout on this on website:
under Resources, Vision Module, Session 4, handout I

26. The Visual System
Wps.prenhall.com

27. Normal Optic Nerve optic nerve macula
National Eye Institute, National Institutes of Health

28. Hydrocephalus
Increased fluid in the ventricles or water spaces of the brain
Put pressure on optic nerve fibers
Prolonged high pressure causes
permanent damage
Putting in shunt to drain fluid soon enough can minimize the damage
Decreased visual functioning can be a
sign of shunt failure
Child with Shunt
Optic nerve head in back
of the eye of 2 year old
child with hydrocephalus

29. Brain Bleeds Around the Ventricles
Optic radiations pass by and around the lateral ventricles
Low birthweight premature babies may suffer brain bleeds in the ventricles
These bleeds can damage the optic radiations, resulting in vision loss
Severity of vision loss depends on the extent of the bleed, treatment, other
medical issues, etc.
Lateral Ventricle
Optic
Radiations
Lateral Ventricle
(other views)
Grade III Bleed
in the Lateral
Ventricals

30. Optic Nerve Atrophy (ONA)
Loss of blood supply to optic nerve with accompanying gradual vision loss
Optic disc is pale when examined
Change in visual acuity and peripheral field may occur before change in the disc is evident; nerve
cells of retina may stop functioning
before the nerve atrophies
Degenerative condition following
normal function
Not normally diagnosed in infancy

31. Optic Nerve Hypoplasia (ONH)
Small optic nerves with normal size blood vessels
Varying degrees of visual acuity and field losses
Associated with CNS anomalies
-agenesis of corpus callosum (failure of two halves of brain to connect)
-endocrine disorders
Incidence increasing, possibly as result of
drugs, alcohol, tobacco use of mother before
birth while pregnant
Booklet on ONH from the
Blind Childrens Center in
Los Angeles, CA

32. Septo Optic Dysplasia de Morsier syndrome
A congenital malformation syndrome manifested by:
- hypoplasia (underdevelopment) of the
optic nerve
- hypopituitarism
- absence of the septum pellucidum (a
midline part of the brain)
In a severe case, this results in pituitary hormone deficiencies, blindness, and mental retardation
There are milder degrees of each of the three problems, and some children only have one or two of the three
emedicine.com

33. Delayed Visual Maturation
Type I: child with normal general/neurological development and
no underlying pathology; by 3-6 months, child has a rapid
improvement of vision to normal or near-normal levels
Type II: associated with systematic disorders of mental retardation;
vision usually improves, but takes longer and there may be
continued loss of vision
Type III: associated with other ocular disorders such as albinism,
cataracts or aniridia; vision worse than expected from
disease alone with mean age of recovery at 20 weeks;
onset of nystagmus precedes recovery which is complete
by 8 months; also depends on visual abilities and other
characteristics of the child