lecture fakulti pendidikan 2011
TRANSCRIPT
Penaksiran dan Diagnosis Kanak-kanak Bermasalah
Penglihatan
Dr Safinaz Mohd KhialdinPensyarah & Pakar Oftalmologi
Jabatan OftalmologiPPUKM
• Visual impairment or low vision • reduction in vision that cannot be corrected
with standard glasses or contact lenses • reduces a person's ability to function at certain
or all tasks
Visual Impairment
• Functional limitation of the eye(s) or visual system
• Can manifest as• Reduced visual acuity • Reduced contrast sensitivity• Visual field loss• Photophobia• Diplopia• Visual distortion
Visual Impairment
• Clearness of vision• dependent on the
sharpness of the retinal focus within the eye
• the sensitivity of the interpretative parts of the brain.
Visual acuity
VISION TESTING IN CHILDREN
Contrast sensitivity
• How well your eyes function in dim light • How well you can distinguish objects from
similarly colored or shaded backgrounds.
• The total area in which objects can be seen in the peripheral vision while you focus your eyes on a central point.
Visual field
PHOTOPHOBIA – glaring
DIPLOPIA – double vision
VISUAL DISTORTION
• Definition:• Visual impairment : • visual acuity of less than 6/18, but equal or
better than 3/60 in the better eye• Visual field less than 20 degree from fixation
• Blindness: • visual acuity is less than 3/60 in the better eye• Visual field less than 10 degree from fixation
Visual Impairment
6/60
6/18
• HISTORY TAKING – SYMPTOMS
• EXAMINATIONS – SIGNS
• INVESTIGATIONS – CONFIRM DIAGNOSIS
EVALUATION & DIAGNOSISOF VISUAL IMPAIRMENT
• Ocular History• Diagnosis and onset of symptoms• Past, current, or planned surgeries or
treatments• Stability of vision• Family history of eye disease• Previous history of eye disease or vision
problems• Current or previous use of spectacles,
contact lenses, or low vision aids
EVALUATION & DIAGNOSIS: HISTORY
• Visual Functioning• Ability to read print and specific reading
needs (schooling)• Intermediate visual ability and needs (e.g.,
use of computer, reading music)• Distance visual ability and needs• Photophobia, glare sensitivity, and lighting
requirements
EVALUATION & DIAGNOSIS: HISTORY
• Medical History• General health review• Current medications• Hearing impairment or other disability• Developmental delay
EVALUATION & DIAGNOSIS: HISTORY
• EXAMINATION• Visual acuity• Visual field• Refraction• Eye movement• Detailed examination of the eye structures
EVALUATION & DIAGNOSIS: EXAMINATION
• To confirm eye problem• Ultrasound• CT scan
• To assess visual impairment• Contrast sensitivity testing• Colour vision testing• Visual evoked potential
EVALUATION & DIAGNOSIS: INVESTIGATIONS
Eye problems in children
Importance Early detection & treatment of peadiatric
ocular disease is critical Delay in diagnosis results in irreversible vision
loss Assessment should begin at birth
• Eye pathology : Structural impairment or damage to one or more parts of the eye
• Refractive errors: or an inability of the eye to sharply focus images on the back of retina
• Cortical visual impairments: damage to the part of the brain that interprets visual information
CAUSES OF VISUAL IMPAIRMENT IN CHILDREN
Eye problems in children causing visual
impairment
Anatomy of the eye
Congenital glaucoma
• Rare (1:10000), 65% males• Diagnosed shortly after birth or during 1st year of life• Improper development of the eye drainage channel• Leads high pressure in the eye• Causing damage to optic nerve and results in vision
loss• Symptoms:• Tearing • Photophobia (glaring)• Excessive squeezing of the eye• Buphthalmos (ox eye)
Leucocoria
• White eye reflex• Differential diagnosis• Retinoblastoma • Congenital cataract• Retinopathy of Prematurity• Coat’s disease• Persistent Hyperplastic Primary Vitreous
(PHPV)
1.Leucocoria: Retinoblastoma
Most common intraocular malignancy of childhood Rare (1 in 14000-20000) 3% of all childhood cancers Bilateral in 30-35% Age at diagnosis : 18 months (90% less than 3
years old) May be inherited
1.Leucocoria: Retinoblastoma
• Present with:• Leucocoria (white reflex)• Squint • Poor vision• Eye redness, pain• Proptosis : forward bulging of the eye• Systemic metastases• Incidental ocular exam
Retinoblastoma
• Sight threatening• Life threatening
• Treatment option• Radiotherapy• Chemotherapy• Surgical removal of the eye• Genetic counselling
2. Leucocoria: Cataract
Definition of cataract : Opacity involving the lens
Leucocoria: Cataract
Leading cause of blindness Interferes with normal
visual develoment Inherited –1/3 Associated with other
diseases – 1/3 Idiopathic – 1/3
Nuclear cataract
Lamellar cataract
Cortical cataract
CONGENITAL CATARACT
SECONDARY
Ocular - Anterior subcapsular – Atopic dermatitis
Systemic – oil droplet cataract – Galactossaemia
Vossius ring in traumatic cataract
Presentations of childhood cataract
Lack of visual interest Strabismus/squint Nystagmus : abnormal movement of the eye Developmental delay Associated with systemic/ ocular
abnormalities
Action
Prompt detection & dedicated screening Referral to Ophthalmologist (urgent) Why?
Monocular/ binocular cataract in infants results in significant visual deprivation
Early visual rehabilitation can prevent amblyopia (lazy eye)
• Eye disease that affects prematurely born babies
• Caused by disorganized growth of retinal blood vessels
• May be mild and resolves spontaneously• Severe cases can lead to scarring and retinal
detachment.
3. Leucocoria: Retinopathy of prematurity
Leucocoria: Retinopathy of prematurity
• Risk factor for ROP• Pre-term babies – screening• Low birth weight• Exposure to oxygen
• Screening of premature babies has to continue till school-going age• Risk of myopia, even with no ROP
Leucocoria: Retinopathy of prematurity
Strabismus/squint
• Definition: Deviation of the eyes so that their visual axes are no longer parallel
Causes of squint
• Muscle imbalance• Refractive errors• Ocular abnormalities – cataract, macular
scar, optic disc pathology• Special syndromes – Duanes, Brown• Associated disease – hydrocephalus,
cerebral palsy, meningitis
Other presenting features
• Symptoms• None• Noted by parents• Poor vision• Funny eye movements
• Signs • Poor vision• Abnormal head posture
Management for squint
• Refer to ophthalmologist (urgent)• Treatment of refractive errors• Treatment of amblyopia (lazy eye)• Ocular exercise• Surgery – mucsle imbalance
• Why? • Amblyopia (Lazy eye)• Loss of binocular single vision• Cosmetic blemish
REFRACTIVE ERROR
• Physiological condition whereby the refracting system of the eye does not focus objects on the retina
• A corrective lens has to be placed in front of the eye to enable a sharp image to be seen.
• Myopia• Hyperopia• Astigmatism
Refractive errors
Refractive errors
• Various presentations:• Squeezing eyes• Squint• Headache – ocular/ frontal/ diffuse• Tearing• Complains of tired eyes• Child is slow at school• Has problems with attentiveness• Strong family history of myopia or other refractive
error
• Importance: Untreated or undertreated will cause AMBLYOPIA
• Visual acuity screening in schools• Performed in Standard 1• Referral to
Ophthalmologist/Optometrist
Refractive errors
Amblyopia
• ‘Lazy eye’
• Definition: • Unilateral/ bilateral decrease of best corrected
visual acuity
• Is potentially reversible during the critical period (before 7-9 years old)
Critical period:Why is visual development
important?
• Sensory function continues to develop after birth• Requires proper visual stimulation• Normal vision – receptive cells, clear media and
normal retina• Normal alignment • Normal brain development
How does amblyopia develop?
• Brain receives stimuli from both eyes
• Child’s maturing brain will select the better image and ignore the blurry image• Vision not properly
developed in the bad eye (AMBLYOPE)
Causes of amblyopia
• Ammetropia (bilateral high refractive error)
• Anisometropia (large/ asymmetrical refractive error difference between eyes)
• Strabismic (squint)• Occlusional / form deprivation (media
problem)
Treatment
• Can be treated or reversed if detected earlier (critical period)
• Treat underlying condition – cataract, squint• Prescribe spectacles correction – refractive error• Force to use the amblyopic eye• Patching the good eye• Putting atropine eye drops to blur image in the
good eye
Visual pathway
• As a result of the damage to the brain.• Cerebral palsy• Seizure disorder• Hydrocephalus, Microcephaly
• Infants and children with cortical vision impairment• Delayed in reaching developmental milestones • Sensory motor & activities and social development.• Intellectual disability
Cortical visual impairments
The process of treatment and education that helps individuals who are visually disable•attain maximum function,• a sense of well being, •a personally satisfying level of independence, •optimum quality of life.
Visual Rehabilitation
• OPTICAL DEVICES• NON OPTICAL DEVICES• HOLISTIC APPROACH• Clinicians – ophthalmologist, peadiatrician,
optometrist• Teachers, Education ministry• Occupational therapist• Counsellors : psychologist, psychiatrist, social
worker• Vocational Rehabilitation centers
Visual Rehabilitation
• OPTICAL DEVICES
• Reduced Visual Acuity• Magnification for near• Magnification for distance
• Central visual field defect• Peripheral visual field defect• Reduced contrast sensitivity• Glare sensitivity
Visual Rehabilitation
HAND HELD MAGNIFIERS
MAGNIFICATION FOR NEAR
STAND MAGNIFIERS
SPECTACLE-MOUNTED MAGNIFIER
CLOSE-CIRCUIT TELEVISION SYSTEM
TELESCOPE
MAGNIFICATION FOR FAR
TREATMENT OF CENTRAL VISUAL FIELD LOSS
MODIFIED TEXT
• Training for eccentric viewing- avoid fixating using the fovea
• Using large print material
• Using prism relocation
TREATMENT OF PERIPHERAL VISUAL FIELD LOSS
MIRROR PRISMS
• Acts like a side mirror of a car• Able to view objects at the non-seeing area
of the eye when glancing into the mirror or prism
TREATMENT FOR REDUCED CONTRAST SENSITIVITY AND GLARE
TINTED LENSES
COLOUR CONTRAST
TYPOSCOPE : reduce reflected glare from printed pages
• NON-OPTICAL METHODS • Move CLOSER: use an angled reading desk• Use COLOUR to show objects more clearly• Use CONTRAST: eat white rice off a coloured plate• Pay attention to LIGHTING: sit near a window in
class• Make objects LARGER: write with larger letters• Use a LINE-GUIDE such as a ruler when reading
and writing.
Visual Rehabilitation
• Prognosis for success depends on:• Ocular condition• Vision loss – nature & extent• Patient – physical & mental abilities,
attitude, expectation, motivation• Clinician – attitude & motivation
Visual rehabilitation
THANK YOU