Strabismus, Strabismus, Amblyopia & Amblyopia & LeukocoriaLeukocoria
Dr. Hessah Alodan, Dr. Hessah Alodan,
Pediatric Opthalmology Dept, Pediatric Opthalmology Dept, KAUHKAUH
Why Two Eyes ?Why Two Eyes ?
You can demonstrate to a patient the difference in their field or their child's field with one eye compared to two. With two eyes you can also demonstrate the peripheral field and the central fusion.
Why Two Eyes ?Why Two Eyes ?
Total binocular field is nearly 170 degrees (varies according to configuration of orbits)
Left Eye Monocular
Binocular
Right Eye Monocular
Why Two Eyes ?Why Two Eyes ?Two Pencils Test
With both eyes open the patient who uses both eyes producing stereopsis can put his pencil accurately on the examiner's pencil if stereopsis is present
The same person with one eye closed or with manifest strabismus or no stereopsis will miss the examiner's pencil initially and place it correctly only after the second or third try.
Visual Axis
Imaginary line between fovea and the object
Binocular Vision
If the visual axises from both eyes intersect at the object, binocular vision occurs
Sensory Fusion
Supper imposed images from each corresponding retinal area in binocular cells at the level of the occipital cortex
1. Same images2. Similar in size3. Similar in clarity
Motor Fusion
Ability to physically move the eyes so that they are pointing in the same direction allowing the corresponding areas of the retina in each eye to be pointing at the object of regard
Visual Axes Misalignment lead to:
1.Confusion
Superimposition of the two different images stimulating corresponding retinal points
2.Diplopia
One object stimulating two none corresponding retinal points
Compensatory mechanism to misalignment of VA :
1.Suppression
Subconscious active neglect of one eye input that occurs only when both eyes are open
2.Amblyopia
Action of extraocular muscles
Muscle Action
All obliques
Abduct
Horizontal Recti
Adduct
All superior muscles
Intort
All inferior
muscles Extort
Action Muscles
Dextroelevation
OD: Superior RectusOS: Inferior Oblique
Dextrodepression
OD: Inferior Rectus OS: Superior Oblique
Levoelevation
OD: Inferior Oblique OS: Superior Rectus
Levodepression
OD: Superior Oblique OS: Inferior Rectus
Right gaze
OD: Lateral Rectus OS: Medial Rectus
Left gaze
OD: Medial Rectus OS: Lateral Rectus
What is Strabismus ?What is Strabismus ?
Ocular misalignment due to abnormality in binocular vision or anomalies in neuromuscular control of ocular motility
Classification of Strabismus:
According to fusion status
1. Phoria Latent tendency of the eye to deviate and
controlled by fusional mechanism
2. Intermittent Phoria Fusion control is present part of the time
3. TropiaManifest misalignment of the eye all the time
Classification of Strabismus:
According to fixation
1. Alternating Spontaneous alternation of fixation from one
eye to the other
2. Monocular Preference of fixation with one eye
Classification of Strabismus:
According to type of deviation
1. Horizontal Esodeviation Exodeviation
2. Vertical Hyperdeviation Hypodeviation
3. Torsional Incyclodeviation Excyclodeviation
4. Combined
Classification of Strabismus:
According to age of onset
1. Congenital
2. Acquired
Classification of Strabismus:
According to variation of the deviation with gaze position or fixing eye
1. Comitant Same deviation in different direction of gaze
2. IncomitantVariable deviation in different direction of
gaze usually in paralytic or restrictive type of strabismus
Examination
1. History
2. Inspection
3. Assessment of monocular eye function
Visual acuity
Preverbal children
CSMOKNPreferential lookingVisual evoked potential
Examination
Assessment of monocular eye function
Visual acuity
Verbal children
Symbol testsSingle illiterate EAllen pictures H O T V letters
Examination
Assessment of binocular eye function
1. Hirschberg test
2. Krimski’s test
3. Cover test
4. Alternate cover test
5. Prism cover test
Examination
Fundoscopy
Cycloplegic refraction
• Tropicamide
• Cyclopentolate
• Atropin
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Type of Strabismus
Esotropia
• Pseudoesotopia • Infantile esotropia• Accommodative esotropia • Partially accommodative esotropia
Pseudoesotropia
• Occur in patients with flat broad nasal bridge and prominent epicanthal fold
• Gradually disappear with age
• Hirschberg test differentiate it from true esotropia
Infantile Esotropia
• Common comitant esotropia occur before six month of age
• Deviation is often large more than 40 prism diopter
• Frequently associated with nystagmus and inferior oblique over action
• Treatment
Correction of refractive errorTreat amblyopiaSurgical correction of strabismus
Accommodative Esotropia
• Occur around 2 ½ years of age
• Start as intermittent then become constant
• High hypermetropia
• Treatment
Full cycloplegic correctionTreat amblyopia
Partially Accommodative Esotropia
• Improve partially with glasses
• Treatment
Full cycloplegic correctionTreat amblyopiaSurgical correction of strabismus
Type of Strabismus
Exotropia
• Intermittent exotropia • Constant exotropia • Sensory exotropia
Intermittent exotropia
• Onset of deviation within the first year of age• Closing one eye in bright light • Usually not associated with any refractive error • Usually not associated with amblyopia
• Treatment
Correction of any refractive error Surgical correction of strabismus
Constant exotropia
• Maybe present at birth or maybe progress from intermittent exotropia
• Treatment
Correction of any refractive errorCorrection of amblyopia Surgical correction of strabismus
Sensory exotropia
• Constant exotropia that occur following loss of vision in one eye e.g trauma
• Treatment
Correction of any organic lesion of the eyeCorrection of amblyopia Surgical correction of strabismus
Types of Strabismus
Paralytic strabismus
• 6th nerve palsy • 4th nerve palsy• 3rd nerve palsy
6th Nerve Palsy
• Incomitant esotropia
• Limitation of abduction
• Abnormal head position
4th Nerve Palsy
• Congenital or acquired
• Hypertropia of the affected eye with excyclotropia
• Abnormal head position
3rd Nerve Palsy
• Congenital or acquired
• Exotropia with Hypotropia of the affected eye
• In children caused by: trauma, inflammation, post viral and tumor
• In adult caused by: aneurysm, diabetes, neuritis, trauma, infection and tumor
Special Types of Strabismus
• Duane strabismus
• Brown syndrome
• Thyroid opthalmopathy
Duane Syndrome
• Limitation of abduction
• Mild limitation of adduction
• Retraction of the globe and narrowing of the palpebral fissure on adduction
• Upshoot or downshoot on adduction
• Pathology faulty innervation of the lateral rectus muscle by fibers from medial rectus leading to co-contraction of the medial rectus and lateral rectus muscles
Brown Syndrome
• Limitation of elevation on adduction
• Restriction of the sheath of the superior oblique tendon
• Treatment needed in abnormal head position or vertical deviation in primary position
Thyroid Ophthalmopathy
• Restrictive myopathy commonly involving inferior rectus, medial rectus and superior rectus
• Patients presents with hypotropia, esotropia or both
Surgery of Extraocular Muscle
• Recession : weakening procedure where the muscle disinserted and sutured posterior to its normal insertion
Surgery of Extraocular Muscle
• Resection : strengthening procedure where part of themuscle resected and sutured to its normal insertion
Complication of Extraocular Muscle Surgery
• Perforation of sclera
• Lost or slipped muscle
• Infection
• Anterior segment anesthesia
• Post operative diplopia
• Congectival granuloma and cyst
AmblyopiaAmblyopia
What is Amblyopia ?
Amblyopia refers to a decrease of vision, either
unilaterally or bilaterally, for which no cause can
be found by physical examination of the eye
Pathophysiology of Amblyopia
amblyopia is believed to result from disuse from inadequate foveal
or peripheral retinal stimulation and/or abnormal binocular
interaction that causes different visual input from the foveae
No retinal changes - ERG OK
Afferent pupil response has been reported but not common
Lateral geniculate layers subserving amblyopic eyes atrophic
Cortical ocular dominance columns representing amblyopic eye less responsive to stimulus and show changes microscopically
Amblyopia
Three critical periods of human visual acuity development have
been determined. During these time periods, vision can be
affected by the various mechanisms to cause or reverse
amblyopia. These periods are as follows:
• The development of visual acuity from the 20/200 range to
20/20, which occurs from birth to age 3-5 years.
• The period of the highest risk of deprivation amblyopia, from a few months to 7 or 8 years.
• The period during which recovery from amblyopia can be obtained, from the time of deprivation up to the teenage years or even sometimes the adult years
Amblyopia
Diagnosis of amblyopia usually requires a 2-line difference of
visual acuity between the eyes
Crowding phenomenon: A common characteristic of
amblyopic eyes is difficulty in distinguishing optotypes that
are close together. Visual acuity often is better when the
patient is presented with single letters rather than a line of
letters
to 20/70
An amblyopic eye with 20/70 full line vision
may be able to see as well20/30 viewing a single optotype
Causes of Amblyopia
Many causes of amblyopia exist; the most important causes are as follows:
Anisometropia
• Inhibition of the fovea occurs to eliminate the
abnormal binocular interaction caused by one
defocused image and one focused image.
• This type of amblyopia is more common in
patients with anisohypermetropia than
anisomyopia. Small amounts of hyperopic
anisometropia, such as 1-2 diopters, can
induce amblyopia. In myopia, mild myopic
anisometropia up to -3.00 diopters usually
does not cause amblyopia.
Causes of Amblyopia
Strabismus
The patient favors fixation strongly with one eye and does not alternate fixation. This leads to inhibition of visual input to the retinocortical pathways.
Incidence of amblyopia is greater in esotropic patients than in exotropic patients
Alternation with alternate suppression avoids amblyopia
Causes of Amblyopia
Visual deprivation
Amblyopia results from disuse or understimulation of the retina. This condition may be unilateral or bilateral. Examples include cataract, corneal opacities, ptosis, and surgical lid closure
Deprivation Amblyopia
Bilateral Deprivation Amblyopia
Causes of Amblyopia
Organic
Structural abnormalities of the retina or the optic nerve
may be present. Functional amblyopia may be
superimposed on the organic visual loss
Causes of Amblyopia
Ametropic Amblyopia
Uncorrected high hyperopia is an example of this bilateral amblyopia.
Treatment
The clinician must first rule out an organic cause and
treat any obstacle to vision (eg, cataract, occlusion
of the eye from other etiologies).
Remove cataracts in the first 2 months of life, and
aphakic correction must occur quickly
Treatment of anisometropia and refractive errors must occur next
The next step is forcing the use of the amblyopic eye by occlusion therapy
LeukocoriaLeukocoria
Causes of LeukocoriaCauses of Leukocoria
CataractCataract RetinoblastomaRetinoblastoma ToxocariasisToxocariasis Coat´s diseaseCoat´s disease ROPROP PHPVPHPV Retinal detachmentRetinal detachment ColobomaColoboma Retinal dysplasiaRetinal dysplasia Norrie´s diseaseNorrie´s disease
• opacification of the lens.
• Congenital cataracts usually are diagnosed at birth.
• If a cataract goes undetected in an infant,
permanent visual loss may ensue.
cataractcataract
Unilateral cataracts are
usually isolated sporadic
incidents
• Bilateral cataracts are often inherited and associated with other diseases.
•They require a full metabolic, infectious, systemic, and genetic workup.
•The common causes are hypoglycemia, trisomy (eg, Down, Edward, and Patau syndromes), myotonic
dystrophy, infectious diseases
(eg, toxoplasmosis, rubella, cytomegalovirus, and herpes simplex [TORCH]), and prematurity
RETINOBLASTOMARETINOBLASTOMA
CLINICALCLINICAL
MANIFESTATIONSMANIFESTATIONS Leukocoria (60%)Leukocoria (60%) Strabismus (20%)Strabismus (20%)
OTHER- Uveitis, Orbital OTHER- Uveitis, Orbital
cellulitis, Hyphaema, cellulitis, Hyphaema, Heterochromia, Heterochromia, Glaucoma, Bupthalmos Glaucoma, Bupthalmos
Retinoblastoma is the most common intraocular tumor of Retinoblastoma is the most common intraocular tumor of childhood.childhood.
RETINOBLASTOMARETINOBLASTOMA
RetinoblastomaRetinoblastoma The disease is bilateral in approximately 30% of cases. The disease is bilateral in approximately 30% of cases.
The average age at diagnosis is 18 months and 90% of The average age at diagnosis is 18 months and 90% of
patients are diagnosed before the age of 3 years. Less patients are diagnosed before the age of 3 years. Less
than 10% of retinoblastoma suffers have a family history than 10% of retinoblastoma suffers have a family history
of the disorder, 90% of cases areof the disorder, 90% of cases are sporadic sporadic. Of the . Of the
sporadicsporadic cases, the responsible mutation is in a germ cases, the responsible mutation is in a germ
cell in 25% of cases and in a somatic cell in 75% of cell in 25% of cases and in a somatic cell in 75% of
casescases
GENETICSGENETICS
Retinoblastoma gene is a recessive oncogene of 180,000 kilobases.Retinoblastoma gene is a recessive oncogene of 180,000 kilobases.
Located chromosome- 13q14Located chromosome- 13q14
Knudson Knudson two hittwo hit hypothesis: hypothesis:
Germinal cells have one defective and one normal RB gene.Germinal cells have one defective and one normal RB gene.
A somatic mutation results in loss of the normal RB gene and hence retinoblastoma develops A somatic mutation results in loss of the normal RB gene and hence retinoblastoma develops
(somatic mutations occur frequently enough in the developing retina, therefore lesions usually (somatic mutations occur frequently enough in the developing retina, therefore lesions usually
affect both eyes)affect both eyes)
In addition, the first child of a parent who had had a unilateral retinoblastoma has a 4% chance In addition, the first child of a parent who had had a unilateral retinoblastoma has a 4% chance
of developing the diseaseof developing the disease
PATHOLOGYPATHOLOGY
Arise in primitive photoreceptor cells.Characteristic histology:Arise in primitive photoreceptor cells.Characteristic histology:
Retinoblastomas are composed of poorly differentiated neuroblastic Retinoblastomas are composed of poorly differentiated neuroblastic
cells with scanty cytoplasm and prominent basophilic nuclei.cells with scanty cytoplasm and prominent basophilic nuclei.
The tumour proliferates rapidly, with a tendency to outgrow its blood The tumour proliferates rapidly, with a tendency to outgrow its blood
supply and undergo spontaneous necrosis. Necrotic tumour being supply and undergo spontaneous necrosis. Necrotic tumour being
eosinophilic stain pink.eosinophilic stain pink.
Characteristic Flexner-Wintersteiner rosettes represent an attempt Characteristic Flexner-Wintersteiner rosettes represent an attempt
at retinal differentiation. Histologically, a ring of cuboidal cells is at retinal differentiation. Histologically, a ring of cuboidal cells is
seen surrounding a central lumen. Cuboidal tumour cells with seen surrounding a central lumen. Cuboidal tumour cells with
basally oriented nuclei arranged around a central lumen.basally oriented nuclei arranged around a central lumen.
RetinoblastomaRetinoblastomaCalcification is another
feature of retinoblastomas,
usually occurring in necrotic
areas. Calcium stains with
H&E. It is worth identifying
calcium in suspect eyes by
ultrasound, or CT scan to
differentiate retinoblastomas
from other tumours.
MANAGEMENTMANAGEMENT EMPIRICAL GENETIC COUNSELLINGEMPIRICAL GENETIC COUNSELLING
ENUCLEATIONENUCLEATION
unilateral, poor visual prognosisunilateral, poor visual prognosis
PLAQUEPLAQUE
4-12mm +/- vitreous seeding4-12mm +/- vitreous seeding
EXTERNAL BEAMEXTERNAL BEAM
>12mm, multiple foci, only eye>12mm, multiple foci, only eye
LASERLASER
consider- indirect, xenon arcconsider- indirect, xenon arc
cryotherapy if <2dd in sizecryotherapy if <2dd in size
CHEMOTHERAPY, if intracranial extensionCHEMOTHERAPY, if intracranial extension
Non-Retinoblastoma Non-Retinoblastoma MalignanciesMalignancies
Unfortunately, children who have genetic retinoblastoma Unfortunately, children who have genetic retinoblastoma
and survive their primary intraocular cancer have a and survive their primary intraocular cancer have a
substantially increased risk of death from one or more substantially increased risk of death from one or more
nonretinoblastoma malignancies over the course of their nonretinoblastoma malignancies over the course of their
lifetimes, up to 35% of children who have had a bliateral lifetimes, up to 35% of children who have had a bliateral
retinoblastoma and external beam radiation therapy will retinoblastoma and external beam radiation therapy will
develop a second cancer by age 25 yearsdevelop a second cancer by age 25 years
Congenital retinal Congenital retinal telangiectasis (Coats' telangiectasis (Coats'
disease)disease) Congenital retinal telangiectasis (Coats' disease) is an Congenital retinal telangiectasis (Coats' disease) is an
idiopathic retinal vascular disorder that usually affects idiopathic retinal vascular disorder that usually affects
young male patients unilaterally in their first or second young male patients unilaterally in their first or second
decade of life.. Patients may present with decreased decade of life.. Patients may present with decreased
vision, as well as strabismus or leukocoria in children. vision, as well as strabismus or leukocoria in children.
The hallmark feature of congenital retinal telangiectasis The hallmark feature of congenital retinal telangiectasis
is localized fusiform aneurysmal dilations of the retinal is localized fusiform aneurysmal dilations of the retinal
vessels reminiscent of tiny light bulbsvessels reminiscent of tiny light bulbs
Persistent hyperplastic Persistent hyperplastic primary vitreous (PHPV)primary vitreous (PHPV)
Persistent hyperplastic primary vitreous (PHPV) is a Persistent hyperplastic primary vitreous (PHPV) is a
congenital anomaly in which the primary vitreous fails to congenital anomaly in which the primary vitreous fails to
regress in utero. Highly vascular mesenchymal tissue regress in utero. Highly vascular mesenchymal tissue
nurtures the developing lens during intrauterine life. In nurtures the developing lens during intrauterine life. In
PHPV, the mesenchymal tissue forms a mass behind the PHPV, the mesenchymal tissue forms a mass behind the
lens.lens.
Persistent hyperplastic Persistent hyperplastic primary vitreous (PHPV)primary vitreous (PHPV)
A gray-yellow retrolental membrane may produce A gray-yellow retrolental membrane may produce
leukocoria, with the subsequent suspicion of leukocoria, with the subsequent suspicion of
retinoblastoma. retinoblastoma.
In PHPV, the globe is white and slightly microphthalmic. In PHPV, the globe is white and slightly microphthalmic.
Patients have no history of prematurity or oxygen Patients have no history of prematurity or oxygen
administration.administration.
RETINOPATHY OF PREMATURITY RETINOPATHY OF PREMATURITY (ROP)(ROP)
Vasoproliferative retinopathy affecting premature infants Vasoproliferative retinopathy affecting premature infants
exposed to high oxygenexposed to high oxygen
INCIDENCEINCIDENCE
Prematurity (<32/40)Prematurity (<32/40)
Birth weight (30% < 1000gm affected)Birth weight (30% < 1000gm affected)
Oxygen durationOxygen duration
90% ROP regresses spontaneously, 5% blindness90% ROP regresses spontaneously, 5% blindness
Signs include:
• neovascularization,
• fibrous bands
• retinal detachments
• vitreous hemorrhage
• leukocoria
RETINOPATHY OF PREMATURITY RETINOPATHY OF PREMATURITY (ROP)(ROP)
Retinal detachment in Retinal detachment in childhoodchildhood
Retinal detachment in childhood can be confused with Retinal detachment in childhood can be confused with
retinoblastoma, and vice versa. The possibility of an retinoblastoma, and vice versa. The possibility of an
underlying retinoblastoma should always be considered underlying retinoblastoma should always be considered
when a child presents with retinal detachment and when a child presents with retinal detachment and
vitreous hemorrhage, even when a history of trauma is vitreous hemorrhage, even when a history of trauma is
obtained. obtained.
Risk factors:Risk factors:
Trauma Trauma
SurgerySurgery
vitreous detachmentvitreous detachment
high myopiahigh myopia
retinal breaks or tears retinal breaks or tears
retinal vascular diseaseretinal vascular disease
history of detachment in the other eyehistory of detachment in the other eye
Retinal detachment in Retinal detachment in childhoodchildhood
SymptomsSymptoms
flashes of lightflashes of light
floatersfloaters
curtain-like decrease in visioncurtain-like decrease in vision
Retinal detachment in Retinal detachment in childhoodchildhood
COLOBOMACOLOBOMA
Optic Disc ColobomaOptic Disc Coloboma Due to failure of closure of Due to failure of closure of
foetal fissure inferiorlyfoetal fissure inferiorly
May be isolated disc or May be isolated disc or
associated chorioretinal associated chorioretinal
colobomacoloboma
Usually sporadic, some ADUsually sporadic, some AD
Can be bilateralCan be bilateral
Visual acuity varies from Visual acuity varies from
normal to NPL.normal to NPL.