infantile cataract Flashcards
define aphakia
the state of having no lense
what is Pseudophakia
the state of having an intraocular lens in situ
when may aphakia and Pseudophakia be observed
these conditions may be observed following surgery
- infantile cataract
traumatic cataract
senile cataract
and this can be bilateral/unilateral
what is the prevelance of infantile cataract
1.9-4.2 per 10,000 live birth in the western world
7.4 per 10, 000 live birth in Asia
what is the most common cause of treatable blindness in childreen
bilateral infantile cataract is the most common cause of treatable blindness
accounts for 5-20% of blindness in children worldwide
does cataract have an hereditary element
22% of cataract in childhood is inherited
mutation screening identified 200 locus and more than 100 causative genes
what is the ateiology of bilateral infantile cataract
idiopathic - most cases
hereditary without systemic disease - approximately 1/3 od cases (autosomal dominant , autosomal recessive or x linked
majority being inherited In an autosomal dominant pattern
metabolic disorders are rare (galactosemia and hypocalcemia) ,
bilateral infantile cataract combined with systemic abnormalities there are many inherited disorders including trisomy 21 , turners syndrome , carniofacial or skeletal deformities , myopathies , neurological disturbances , many of these children have associated mental retardation
intrauterine infections , rubella , toxoplasmosis , cytomegalovirus virus , herpes infections , varicella , syphillis
what are the aetiologies for unilateral infantile cataract
idiopathic- most cases
heriditary and or systemic diseases are rare causes
lentconus/ lentiglobyus and persistent feral vasculature (pfv) may be noted in some
associated ocular disease
micropthalmua , anterior segment dysgrensis , persistent foetal vasculature
heriditary and or systemic disease e
rare ateiology
very low birth weight less than 1500 gram is associated with unilateral cataract
other causes of cataract in childhood include
trauma
juvenile ocular inflammatory diseases
uveitis
what are the different types of cataract
different types of cataract
nuclear
cortical
lamellar
anterior polar cataract
anterior subcapsualr cataract
sutural cataract
posterior cataract
posterior letinconus/lentiglobus
traumatic cataract
what is the most common type of cataract
nuclear 54% is the most common type followed by cortical 25% these two are also associated with posterior capsular opacities
what associated ocular conditions are commonly seen with infantile cataract
associated ocular conditions commonly seen with infantile cataract
- persistent fetal vasculature- PFV- developmental abnormality of the primary virtuous and hyaloid vascular system
risk of developing glaucoma - early surgery indicated
anterior segment dysgensis
anriidia
iris colomboma
lens coloboma
what is the management of infantile cataract
early adequate and aggressive therapy allows for the best visual outcome
multidisciplanry approach
early referral
detailed pre-op investigation
early surgery
mulitdisciplanry post- op care
delivery of care - argued designated centres provide a higher concentrated level of speciality care
what presenting signs and symptoms may someone with infantile cataract present with
leukocoria
poor vision/poor visual behaviour
nystagmus
strabismus
micropthalmos
who is involved in the multidisciplinary pre- op investigation
pads - general development of child
signs of metabolic disease or other conditions
any dysmorphic features
ophthalmologist - to check for a red reflex
unilateral or bilateral cataract
density and position of cataract
associated ocular conditions
Examination under aneesthesiia
normal iop in infants is 10 mmhm
geneticist - for genetic counselling
how are optometrist and vision scientists involved in the pre- op investigation
Optometrist
Refractive error
Microphthalmos high hypermetropia
Vision Scientist
Pattern / flash VEP’s
Can detect inter-ocular acuity differences
Disadvantages
Expensive
Time consuming
Not widely available
what is the role of orthoptist pre - operatively
Detailed case history
Ask parents regarding visual behaviour
Visual assessment
Response to light switched on / off
Ability to fixate & follow in all positions of gaze
Fixation patterns (steady / unsteady)
FCPL cards
Presence of deviation
Esotropia / exotropia
Common in unilateral cases
CT: maybe only possible by CR’s only
Presence of nystagmus
Rowing eye movements
Large amplitude, low frequency & pendular waveform typical
Presence of BSV
Relate to age (usually infants <3/12 old)
Measure deviation
PRT / Hirshberg / Krimsky
what information needs to be relayed to parents
Bilateral cataract bilateral stimulus deprivation i.e. surgery essential
Unilateral cataract: parents choice whether to treat
Must inform parents therapy involves
Surgery
Potential post-op complications
Possible need for further surgery
Occlusion until 7 yrs of age
Optical correction for life
Frequent hospital visits especially for 1st 7 yrs of life
when should active management be discarded
Poor GH - systemic disease
Severe other ocular disease
ROP
Toxoplasmosis
Absent flash VEP
Parents refuse post-op occlusion/ child and/or parents are unlikely to manage post-op occlusion
Marked microphthalmos
Severe PFV (persistent fetal vasculature)
Mental retardation non-compliance with post-op therapy
what are options for surgery
Options
Remove lens (lensectomy) APHAKIC
Remove lens + IOL implant
PSEUDOPHAKIC
Posterior capsulotomy with anterior vitrectomy and IOL implant is the surgery of choice in pediatric patients
when is surgery indicated in older children
if partial cataract which does not greatly impede on visual axis , orthoptist and ophthalmologist may closely observe only
frequently seen in lamellar cataracts
when is surgery indicated in infants
surgery for dense infantile cataract is reccommded as early as possible
ideally within the first 6-8 weeks of life
what surgical techniques are used for cataracts
Lensectomy + use of aphakic contact lenses has been the ‘gold standard’ method of managing infantile cataract
Small incision lens extraction, anterior vitrectomy & posterior chamber IOL implant
Preferred method in paediatric patients
IOL in infants (<1 years of age) is controversial
Some infants are left aphakic
Bilateral infantile cataracts
Surgery on BE at the same time / within 1 week to avoid amblyopia
what are the advantages of having g an intrauouclar lens implant and disadvantages
- no difference in image size/ optical abberations
overcome handling/wearing problems associated with contact lenses
disadvantages
require near refraction
intracoular power lens calculation difficult due to large myopic shift especially first 12-18 months of life
posterior capsular opacification very common
what is the intaocular lens power caculation surgery technique
Aim: insert IOL that will render patient emmetropic
No universally accepted paediatric formulae
Under-correction of the emmetropic IOL
calculation advocated
Literature suggest ~6-10D under-correction in infants to allow for myopic shift
IOL power usually range between +24-29 D in infants
what proportion of adults and children will be left aphakik
only a small proportion of adults and older children will be left aphakik post op
which patients may be unsuitable for intrauouclar lens implants and left aphakik post op
patients that may be suitable for iol implant and left aphakik post op include
Traumatic cataract
Glaucoma
High myopia
Severe uveitis
Previous retinal detachment
Corneal opacities
Aphakia in fellow eye
Complications during cataract surgery
vitreous loss with/without loss of capsular bag, choroidal bleeding &/or anterior chamber loss
what are post surgery complications that can occur
post capsular opacification
treated with yag laser capsuolotomy
Pupil decentration /
pupil capture
Iris damage
Retinal detachment
Post-op inflammation – endophthalmitis
what is the most sight threatening glaucoma complication and what are the risk factors
2° glaucoma/aphakic glaucoma
Common complication & most sight threatening
Most develop later onset ‘chronic’ OAG
Onset varies from months to decades
Risk factors
Surgery <2 months old
Microcornea
Nuclear cataract
PFV
Retained lens material & need for 2° surgery
Acute glaucoma
Excessive inflammation pupillary block & iris bombe
what complications occur only after having intraoucalr implants
Posterior capsular opacification
IOL decentration
Shrinkage of capsular bag
how are patients managed post operatively
immediate post op
topical treatment to avoid post open inflammation and synchenia formation
optical correction of aphakia - essential to limit severity of amblyopia and allow development of bincularity
options - contact lens
spectacles are unnaceptbale in unilateral cataract , due to anieskonia , peripheral image distortion and weight imbalance
fit contact lenses in theatre or within 1st few days post op
define anisekonia
Aniseikonia is the difference in image size perceived between the eyes from unequal magnification.
how are aphakic eyes optically corrected
Lens power
Usually b/w +20 to +35D
Aim to overcorrect by
~3D (<1 year)
~2D (1-2 years)
~1D (>2 years)
Aged ~3 years child given reading glasses / bifocals
Glasses must be prescribed for use when CL’s are not in place
how are Pseudophakic eyes corrected
May give optical over-correction (1.5-3D) immediate post-op to provide clear near vision
Aged 2-3 years require near Rx (usually bifocal)
how old does a child have to be remove contact lenses
Children >6 years of age can successfully care for, insert and remove their own CL’s provided they receive a step-by-step training scheme using child friendly language (Dewsbery, 2004)
what are the disadvantages of contact lense wear for post op management
Problems
Non-compliance
Frequent loss
Frequent CL-checks and change of CL
Rapid change of refractive error in young children
Potential side-effects
‘Red eye’
Keratitis
hypoxic corneal ulceration
corneal vascularisation
what are the advantages of contact lense wear as an option for post op management
Advantages
Well tolerated by most (>90%)
Pt’s prefer CL over aphakic glasses
Severe side-effects uncommon
when is intraocular lens surgery indicated
Controversial < 1 year
Infant Aphakia Treatment Study Group (2014)
Examined unilateral cataract cases who had surgery < 6 months.
Follow up until 5 years.
Similar outcomes:
Visual acuity and prevalence of strabismus
IOL implant group had more adverse events and/or required additional surgery
Conclusion: IOL implant surgery reserved for those unable to cope with CL wear
what type of amblyopia do pts with infantile cataract have
Stimulus deprivation amblyopia is more severe & less reversible than
strabismic/anisometropic amblyopia
The reversibility of amblyopia depends on:
Stage of maturity of the visual system at which the abnormal experience began
Duration of stimulus deprivation
Age at which therapy was initiated
what is the main goal of orthoptic management
Amblyopia therapy
Most critical period for visual development
Thought stimulus deprivation before the age of 2-3 months may
severe & permanent visual loss & development of nystagmus
If visual deprivation occurs after 2-3 months
Amblyopia is reversible to some extent
what does the visual outcome of amblyopia therapy depend on
Visual outcome depends on:
Age of onset
Unilateral versus bilateral cataract
Other ocular abnormalities/ diseases
Timing of surgery
Post-operative complications
Outcome of amblyopia therapy
Several studies suggest that better visual outcomes are attained when surgery is performed before 6-8 weeks of age
No difference in visual acuity at 1 ye
how is amblyopia therapy initiated in unilateral cataracts
Unilateral cataracts
Start occlusion as soon as media is clear & optically corrected
Often needs to be intensive
Maintenance occlusion required until 6-7 years of age!
Compliant pt’s who had early Sx might stop occlusion earlier
Occlusion regime is controversial
Some advocate 25% to 50% of patching of waking hours, others 80%
how is amblyopia therapy initiated in bilateral cataracts
Alternating occlusion
Occlusion if 1 eye more amblyopic
how is the presence of nystagmus treated
Presence of nystagmus
Optical penalisation (+3.00DS)
Optical penalization is a treatment for nystagmus that involves using corrective lenses to blur the vision in one eye. This can help to reduce the severity of nystagmus and improve visual function.
The presence of nystagmus can be treated with optical penalization of +3.00DS in the following ways:
Full-time optical penalization: This involves wearing the corrective lenses all the time, including when reading and watching television. This can be the most effective treatment for nystagmus, but it can also be the most challenging to adjust to.
how long is occlusion therapy done in these patients
Occlusion therapy until 7 yrs old!
Achieving long-term compliance
Problem as child gets older & having maintenance occlusion
Compliance rates reported varies 35%-100%
Leaflets: parents understanding
Diary
Frequent monitoring & encouragement
Infantile cataract family help groups
Optical penalisation - opaque CL / +3.00DS
Main factors of achieving optimum VA:
Compliance with optical correction and amblyopia therapy
how strabismus associated with infantile cataracts post operativley- is it higher in unilateral or bilateral cases
Surgery is recommended to be performed before 6-8 weeks to get maximum visual outcome. The same is the case to minimise motor outcomes such as strabismus and nystagmus
The frequency of strabismus is higher in unilateral cataracts (50-90%) compared to bilateral cataracts (40-60%). The prevalence of strabismus may be largely related to the position of the opacity and duration and density of form deprivation. Those with minor opacities such as lamellar, sutural, sectorial and polar cataracts are less likely to develop strabismus (Forster et al. 2004).
what Is the prevalence of strabismus in different groups of treatment for infantile cataract
The Infant Aphakia Treatment Study (IATS) is a multicenter, randomised controlled clinical trial study in the USA comprising of 114 infants
Timing of surgery 2 strata groups:28-48 days (<6 weeks) vs 49-210 days (>6 weeks to 7 months)
Prevalence of strabismus pre-op and post-op same in IOL and aphakia group
Prevalence of strabismus pre-op: 25%
43% esotropia and 57% exotropia
Early Sx: 6% had strabismus pre-op
Late Sx: 39% had
strabismus pre-op
Concluded strabismus is more likely to develop in infants who undergo surgery after 6 weeks of age (critical period for development of BSV! Birch et al )
what is the likelihood of developing bsv post op
Bilateral cataract more likely to demonstrate BSV than unilateral cataract pt’s.
Commonly, only gross stereopsis present
Early surgery higher chance of binocularity with stereoacuities of 50-310’’(Lloyd et al. 1995)
Better binocular functions may be observed with IOL implant than aphakic CL correction (de Decker et al. 1993)
describe the association between nystagmus development and the treatment of infantile cataract
Nystagmus may be present before the cataract surgery, and frequently presents as roving eye movements. However nystagmus may first develop after the surgery. A higher proportion of bilateral cataract cases develop nystagmus. The later the surgery is performed (later than 2-3 months) the more likely nystagmus will develop.
Some believe the presence of manifest nystagmus indicates poor visual prognosis after cataract surgery while others suggest that good outcome can be achieved, at least in some patients (Rabiah et al. 2002).
The majority of children experiencing profound form deprivation as a result of dense opacities such as nuclear, posterior lenticonus, PHPV and posterior polar cataracts ultimately exhibit nystagmus. The most common type of nystagmus recorded by eye movement equipment is manifest-latent nystagmus (MLN) (Forster et al. 2004). The critical period for steady fixation and ocular alignment may be less than 3 weeks of life which further support the need for early surgery (Forster et al. 2004). The nystagmus intensity may dampen in some children following cataract surgery (Rabiah et al. 2002)
Some unilateral cataract cases (children and adults) with no perception of light (PL) or PL only may develop nystagmus (usually vertical) in the affected eye only. This is known as the Heiman-Bielschowsky phenomenon
what happens if cataract is left untreated
Many opacities do not change with time
A few reabsorb spontaneously
rubella, PFV or particular syndromes
Another few may swell, inducing pupillary block & glaucoma
Small opacities can have relatively minor effect on visual development
Treatment may involve optical correction and occlusion only
Monitor closely
