2. • Severe visual impairment and blindness in children have many etiologies and may be
caused by multiple defects affecting any structure or function along the visual pathways
• The most common causes occur during the prenatal and perinatal time periods; the
cerebral-visual pathways, optic nerve, and retinal sites are most often affected.
• Perinatal/neonatal causes include retinopathy of prematurity, hypoxia–ischemia, and
infection
• Severe visual impairment starting in older children may be due to central nervous
system or retinal tumors, infections, hypoxia–ischemia, injuries, neurodegenerative
disorders, or juvenile idiopathic arthritis.
INTRODUCTION
3.
4. Visual impairment includes low vision as well as blindness.
VISUAL IMPAIRMENT
ETIOLOGY :
• Refractive error remains the prime in causing avoidable and reversible blindness in
children.
• Hyperopia afflicts virtually every neonate and declines gradually to reach minimal
proportions in the preschool age group
• Myopia ranges from 4.5% to 10.5% with incidence increasing from 4.5% in preschool
age to 10.5% at 9–13 years, coinciding with pubertal growth spurt echoing in elongation
of eyeball
• Other causes are corneal, lenticular, retinal, glaucomatous and congenital anomalies.
5. COMMON PROBLEMS OF EYE
Red eye
pain in eye
watering eye
wobbly eye and
eye with poor vision
A FEW INDICATORS OF AN EYE PROBLEM IN CHILD
Excessive tearing: This may indicate blocked tear
ducts
Red or encrusted eye lids: This could be a sign of an
eye infection Constant eye turning: This may signal a
problem with eye muscle control
Extreme sensitivity to light: This may indicate an
elevated pressure in the eye or keratitis
Appearance of a white pupil: This may indicate the
presence of an eye cancer or a cataract
12. AMBLYOPIA
This is a decrease in visual acuity, unilateral or bilateral, that occurs in visually immature children
as a result of a lack of a clear image projecting onto the retina
• The unformed retinal image may occur secondary to a deviated eye (strabismic amblyopia)
• an unequal need for vision correction between the eyes (anisometropic amblyopia)
• a high refractive error in both eyes (ametropic amblyopia)
• a media opacity within the visual axis (deprivation amblyopia).
Amblyopia is usually asymptomatic and can avoid detection until vision screening, which may
delay diagnosis as screening programs often target school-age children.
13.
14. MYOPIA
• Parallel light rays from distant objects are focused in front of the retina, whereas diverging
rays from near objects focus on the retina without any requirement for accommodation.
• This error ensues as a consequence of a large globe (axial myopia) or increase curvature of
refractive medium (steep cornea, curvatural myopia).
• Myopia usually progresses with age at a rate of 1 D/year to stabilize during adolescence
15. DIPLOPIA
• Diplopia, or double vision, is generally a result of a misalignment of the visual axes.
• Occluding either eye relieves the diplopia if it is binocular in origin.
• Affected children commonly squint, cover 1 eye with a hand, or assume an abnormal
head posture (a face turn or head tilt) to alleviate the bothersome sensation.
• These behaviors, especially in preverbal children, are important clues to diplopia
TYPES : 1. MONOCULAR DIPLOPIA
2. BINOCULAR DIPLOPIA
16.
17. ASTIGMATISM
• Astigmatism is a result of defocusing of rays in one direction due to variations in
symmetry of corneal and rarely lenticular curvatures.
• Measured in cylinders (Dcyl), it is a common entity in children up to 3 years of
age and resolves spontaneously by 3–5 years.
18. AMAUROSIS
• Amaurosis is partial or total loss of vision; the term is usually reserved for profound
impairment, blindness, or near blindness
• When amaurosis exists from birth, primary consideration in the differential diagnosis must be
given to developmental malformations, damage consequent to gestational or perinatal
infection, anoxia or hypoxia, perinatal trauma, and the genetically determined diseases that
can affect the eye itself or the visual pathways
• Amaurosis that develops in a child who once had useful vision has different implications. In
the absence of obvious ocular disease (cataract, chorioretinitis, retinoblastoma, retinitis
pigmentosa), consideration must be given to many neurologic and systemic disorders that can
affect the visual pathways
19. CLINICAL MANIFESTATIONS OF AMAUROSIS
• Impairment of vision vary with the age and abilities of a child, the
mode of onset, and the laterality and severity of the deficit. The
first clue to amaurosis in an infant may be nystagmus or strabismus,
• Timidity, clumsiness, or behavioral change may be the initial clues
in the very young. Deterioration in school progress and indifference
to school activities are common signs in an older child. School-age
children often try to hide their disability and, in the case of very
slowly progressive disorders, may not themselves realize the
severity of the problem; some detect and promptly report small
changes in their vision.
20. STRABISMUS
• Strabismus, or misalignment of the eyes, is one of the most common eye
problems encountered in children, affecting approximately 4% of children
younger than 6 yr of age
• The word strabismus means “to squint or to look obliquely
21. SUPPRESSION
• In the presence of strabismus, diplopia occurs secondary to the same image falling on
different regions of the retina in each eye.
• In a visually immature child, a process may occur in the cortex that eliminates the disability
of seeing double.
• This is an active process and is termed suppression. It develops only in children.
• Although suppression eliminates the annoying symptom of diplopia, it is the potential
awareness of a second image that tends to keep our eyes properly aligned.
• Once suppression develops, it may allow an intermittent strabismus to become constant or
strabismus to redevelop later in life, even after successful treatment during childhood.
22. NYCTALOPIA
• Nyctalopia, or night blindness, is vision that is defective in reduced
illumination.
• It generally implies impairment in function of the rods, particularly
in dark adaptation time and perceptual threshold.
• Stationary congenital night blindness may occur as an autosomal
dominant, autosomal recessive, or X-linked recessive condition.
• It may be associated with myopia and nystagmus.
• Children may have excessive problems going to sleep in a dark
room, which may be mistaken for a behavioral problem
• it occurs also in vitamin A deficiency or as a result of retinotoxic
drugs such as quinine
