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Introduction. Opacity in lens Can be: Visually significant or not Stable or Progressive Congenital or Acquired Unilateral or Bilateral Partial or Complete Congenital: incidence 6/10 000
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Introduction • Opacity in lens • Can be: Visually significant or not Stable or Progressive Congenital or Acquired Unilateral or Bilateral Partial or Complete • Congenital: incidence 6/10 000 10% of childhood blindness
Classification : Acquired cataracts • Systemic diseases : Diabetes mellitus : Myotonic dystrophy : Atopic dermatitis : Neurofibromatosis 2 • Ocular diseases : Chronic anterior uveitis : High myopia : Fundus dystrophies eg Retinitis pigmentosa • Drugs : Corticosteroids : Chlorpromazine • Trauma : Blunt : Sharp
Congenital cataracts: Bilateral • Genetic Mutation : Autosomal Dominant • Metabolic : Galactosaemia : Lowe : Hypoparathyroidism : Fabry • Infective : TORCH organisms • Chromosomal : Trisomy 21 (Down) : Trisomy 18 (Edward) : Trisomy 13 (Patau) • Skeletal : Hallerman-Streiff : Nance-Horan • Ocular anomalies : Aniridia : Anterior segment dysgenesis syndrome • Idiopathic : in 50%
Congenital Cataracts • Responsible for nearly 10% of all visual loss in children worldwide • Approximately 0.03% of newborns have some form of congenital cataract • Most are not associated with additional developmental problems • Around one fifth of these patients have a family history of congenital cataract but in up to half of all cases there is no family history
Congenital cataract surgery Cataract surgery in children, although complex and time consuming , can have excellent results. Unilateral or bilateral Cause : usually no cause is found
Cataract Types 1)Polar Cataract 2)Lamellar Cataract 3)Sutural Cataract 4)Coronary Cataract 5)Cerulean Cataract 6)Nuclear Cataract 7)Capsular Cataract 8)Membranous Cataract
5)Cerulean Cataract(Blue Color) • Cerulean cataracts are opaque areas that develop in the lens of the eye that often have a bluish or whitish color. They may be present at birth or develop in very early childhood, but may not be diagnosed until adulthood.[1] They are usually bilateral and progressive.[2] Infants can be asymptomatic, but may also be visually impaired from birth and develop nystagmus and amblyopia.[2] In adulthood, the cataracts may progress, making lens removal necessary.[1] Cerulean cataracts may be caused by mutations in several genes, including the CRYBB2, CRYGD, and MAF genes, and are inherited in an autosomaldominant manner. No treatment is known to prevent cerulean cataracts, but frequent evaluations and cataract surgery are typically required to prevent amblyopia as the opacities progress.
Unilateral cataract • Unilateral cataracts are more likely to cause visual loss because of the competition between the two eyes
Congenital cataracts: Unilateral • Sporadic, no family history • Ocular anomalies : Persistent fetal vasculature(PHPV) • Cause identified in only 10%
Etiology There is no benefit in doing a large number of tests and investigations on all children with cataract. It is better to take a careful history. • Family history • Any illnesses or drugs used during the pregnancy • Pediatric consultation • Intra – uterine infection ( rubella , cytomeygalovirus , syphilis) • Hereditary systemic disorders Downs syndrome Turners syndrome , Stickler syndrome
Etiology of Pediatric Cataracts • Hereditary • Autosomal dominant form most common • Genetic and Metabolic Diseases • Down syndrome • Marfan’s syndrome • Myotonic Dystrophy • Maternal Infections • Rubella, Syphilis, Toxoplasmosis, Varicella
Rubella VirusRubella virus is the pathogenic agent of the disease Rubella, and is the cause of congenital rubella syndrome when infection occurs during the first weeks of pregnancy. Humans are the only known host of this virus.Rubella virus is the only member of the genus of Rubivirus and belongs to the family of Togaviridae, whose members commonly have a genome of single-stranded RNA of positive polarity which is enclosed by an icosahedral capsid.The molecular basis for the causation of congenital rubella syndrome are not yet completely clear, but in vitro studies with cell lines showed that Rubella virus has an apoptotic effect on certain cell types. There is evidence for a p53-dependent mechanism.
Syphilis BacteriaTreponemapallidum is a Gram-negative spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta and yaws. The treponemes have a cytoplasmic and outer membrane. This bacterium can be detected with special stains, such as the Dieterle stain.
Stickler syndromeStickler syndrome (hereditary progressive arthro-ophthalmopathy) is a group of genetic disorders affecting connective tissue, specifically collagen. [1] Stickler syndrome is a subtype of collagenopathy, types II and XI. Stickler syndrome is characterized by distinctive facial abnormalities, ocular problems, hearing loss, and joint problems. It was first studied and characterized by Gunnar B. Stickler in 1965.
Turner syndrome or Ullrich–Turner syndrome (also known as "Gonadal dysgenesis"[1]:550), 45,X, encompasses several conditions in human females, of which monosomy X (absence of an entire sex chromosome, the Barr body) is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent (unaffected humans have 46 chromosomes, of which two are sex chromosomes). Normal females have two X chromosomes, but in Turner syndrome, one of those sex chromosomes is missing or has other abnormalities.
Common symptoms of Turner syndrome include: • Short stature • Lymphedema (swelling) of the hands and feet • Broad chest (shield chest) and widely spaced nipples • Low hairline • Low-set ears • Reproductive sterility • Rudimentary ovaries gonadal streak (underdeveloped gonadal structures that later become fibrosed) • Amenorrhoea, or the absence of a menstrual period • Increased weight, obesity • Shield shaped thorax of heart • Shortened metacarpal IV • Small fingernails
Characteristic facial features • Webbed neck from cystic hygroma in infancy • Coarctation of the aorta • Bicuspid aortic valve • Poor breast development • Horseshoe kidney • Visual impairments sclera, cornea, glaucoma, etc. • Ear infections and hearing loss • High waist-to-hip ratio (the hips are not much bigger than the waist) • Attention Deficit/Hyperactivity Disorder or ADHD (problems with concentration, memory, attention with hyperactivity seen mostly in childhood and adolescence) • Nonverbal Learning Disability (problems with math, social skills and spatial relations) • Other features may include a small lower jaw (micrognathia), cubitus valgus,[8] soft upturned nails, palmar crease, and drooping eyelids. Less common are pigmented moles, hearing loss, and a high-arch palate (narrow maxilla). Turner syndrome manifests itself differently in each female affected by the condition, therefore, no two individuals will share the same features.
When to operate • If a child is behaving and developing normally, do not operate , but keep under review. • Do not be misled by the red reflex as children may see remarkably well despite a copsular cataract through which no red reflex is visible
Loss of accommodation by surgery 3) Removing a cataract in a child removes their ability to accommodate.
The visually significant cataract • In central visual axis, bigger than 3mm • Posterior cataract • No clear zones in between • Retinal details not visible with direct ophthalmoscope • Nystagmus or strabismus present • Poor central fixation after 8 weeks
Treatment • Surgery: Cataract extraction and intraocular lens implantation for visually significant cataract • By 6 weeks of age • Bilateral cases: 1 week apart • Non visually significant cases : careful observation, possible pupillary dilation
Surgery • Cataract surgery in children is very different to a cataract surgery in adults. • Children do not have a hard lens nucleus so it can be removed by aspiration alone. • Anterior vitrectomy is necessary after complete lens aspiration. • An intact rim capsule is necessary.
IoL insertion It is possible to insert an ioL at the time of surgery or later as secondary procedure. Anterior capsule of a child is much more elastic than an adult lens. So capsulorhexis is more difficult.
Post capsule If the capsule is left intact , it will opacify.
Lensectomy It is belter to do lensectomy under 5 years of age and ECCE on older children for less risk of amblyopia. So vision lost from capsule opacity can be regained.
How to prevent amblyopia In infants it is essential to correct aphakia as soon as possible after surgery. • One option is to implant an IoL when the cataract is removed. • Second option is contact lens . • Third option is wearing glasses .
Problems with IoL At birth the human lens is more spherical than in adults. It has a power of about 30 D, which compensate for the shorter axial length of a baby's eye. This decreases to about 20 – 22 D by the age of five. So an Iol which gives normal vision to an infant will lead to significant myopia when he or she is older.
IoL correct power ? Since corneal power of the cornea and axial length of the globe, changes are most rapid during the first few years of life and this makes it almost impossible to predict the correct power of lens for IoL in any infant.
IoL Implantation IoL implantation has become quite routine for older children, but it is still very controversial in younger children, particularly those under two years old.
Post operative care In children the surgery is only the beginning of a prolonged course of treatment for prevention of amblyopia.
