Aravind Eye Hospital & Postgraduate Institute of Ophthalmology Etiology of congenital Cataract Dr.P.VijayalakshmiChief Paediatric Ophthalmology & Strabismus

Cataract blindness in children  Constitutes 10-40% of childhood blindness  Dandona et al (India)-15%  Rahi et al (India)-12%  Tailor et al (USA)-15%

Cataract blindness in children Study by Rahi et al (India, blind school) Unoperated cataract-40% Uncorrected aphakia & amblyopia -40% Unsuccessful surgery / post operative complications-20 %

Etiology and Development of the lens  Lens structures include embryonal, fetal nuclei, cortex, lens epithelium & lens capsule  Because of the layered development of the lens the timing of intrauterine insult can be judged by the location of the opacity  Since lens and other anterior segment structure interrelated during development the abnormalities many times coexist

Etio Pathogenesis  Water soluble proteins - the crystallins (90%)  Water insoluble proteins  Membrane proteins (MIP)  Cytoskeletal proteins  Oxidative damage of the crystallins causes cataract  Genes encoding all the crystallins have been mapped in humans

Etiology & laterality  Only 60% of Bilateral cataract and 40% of Unilateral cataract can be established with specific etiology  Others are undetermined

Congenital cataract Hereditary, genetic Metabolic Secondary Embryodisgenesis Etiology

Etiology  Hereditary factors  Non hereditary factors

Hereditary form  Isolated hereditary congenital cataracts  Cataracts associated with ocular disorder  Cataract associated with autosomal syndrome  Cataract associated with metabolic disorder

Isolated Hereditary Cong. Cataract ( inheritance)  Autosomal dominant  Most common  Variable expressivity with high penetrance  Different morphology in families and in individuals  Autosomal recessive  Less common responsible for metabolic disorders

Isolated Hereditary Cong. Cataract ( inheritance)  X-linked inheritance - 3 forms  Dense cataract in affected male Sutural cataract in carrier female  Associated with microcornea and microphthalmos  Cataract & dental anamolies ( Nancy Horan syndrome)

Hereditary  New mutation (50%)  Familial (8-23%) Dominant & recessive  Chromosomal trisomy 21,13,31,18,32, turners  Systemic disease- lowes, Hallerman shreif, conradis, potters, sticklers,cockayne

Isolated Hereditary Cong. cataract (Morphology)  Pulverulent  Anterior polar  Posterior polar  Nuclear  Lamellar  Sutural  Blue dot cataract  Total cataract

Pulverulent Cataract  Inherited as autosomal dominant - 2 types  Zonular pulverulent cataract (Coppock cataract)  Central pulverulent cataract  Typically bilateral & symmetrical  Genes located at Chromosome 1q, 2q & 13q  Mutated genes - connexin 50 & crystalins

Anterior polar cataract  Inherited as autosomal dominant  Opacity situated at the anterior pole of the lens  Minimal effect on visual acuity  Usually unilateral & stationary  Gene located at chromosome 17p

Posterior polar cataract  Inherited as autosomal dominant or autosomal recessive  Small opacity at post capsule  Can cause gross visual impairment  Can present as posterior lentiglobus  Gene located at chromosome 1p 36

Nuclear cataract  Inherited as AD, AR or X-linked  Opacification of central zone of lens specifically the region between the anterior & posterior sutures  Usually bilateral with variable density  gene located at chromosome 21 q  Mutated gene -  crystelins

Lamellar Cataract  Inherited as autosomal dominant  Lamella of lenticular opacification sandwitched between clear nucleus and cortex  Usually bilateral with variable density  Gene located at chromosome 2q

Sutural cataract  Inherited as X-linked trait  Opacities of lens sutures  Seldom impairs vision  Gene located at chromosome 17q

Blue dot cataract  Autosomal dominant  Multi coloured dot like opacities  Genes located at 17q and 22q

Total cataract  Autosomal dominant  Complete opacification of lens  Usually bilateral and often begins as lamellar or nuclear cataract  Gene located at chromosome 10q  Mutated gene Pitx 3

Cataract associated with Ocular disorders Anterior segment disorders  Aniridia  Anterior segment dysgenesis  Peter’s anomaly  Microcornea  Microphthalmia  Coloboma  Posterior lenticonus

Cataract associated with Ocular Disorder Posterior segment disorder  Mittindorf’s dot  PHPV  Retinitis pigmentosa  Lebers congenital amaurosis Contd..

Cataract associated with Autosomal syndrome  Chondrodysplasia punctata (AD, AR or x-linked)  Hallerman -shrief syndrome (AD or AR)  Myotonic dystrophy (AD)  Neurofibromatosis type II (AD)

Cataract associated with Autosomal syndrome  Stickler syndrome (AD)  Bardt- Biedl syndromes (AR)  Cockayane syndrome (AR)  Usher disease (AR)  X - linked - Alport’s syndrome  Marfan’s syndrome Contd..

Cataracts associated with Metabolic disorder  Galactosemia (AR)  G6PD deficiency (AR)  Hypocalcemia (X-linked)  Lowe syndrome (X-linked)  Fabry disease (X-linked)

Cataract associated with Chromosomal anomalies  Down syndrome (Trisomy 21)  Trisomy 10q, 13, 18 & 20p  Turner syndrome (XO)  Chromosome translocation 3:4, 2:14, 2:16

Non hereditary factors  Maternal illness  Maternal drugs  Maternal nutrition  Prematurity  Radiation  Photocoagulation  Steroid intake  Trauma Acquired

Maternal illness  Intrauterine infections caused by Rubella virus, Toxoplasmosis, Cytomegalo virus, Herpes Zoster and Simplex

Rubella cataract  Caused by the virus getting into the developing lens  Characterised by central nuclear cataract usually bilateral  Associated ocular findings are microcornea, glaucoma, keratitis and retinopathy  Systemic associations are deafness and mental retardation

Aetiology of nontraumatic Cataract in children (0-15 yrs) in South India CaseNo. of eye % Hereditary Cong.Rubella Syndrome Secondary Others30.8 Undermined Total BJO 1996; 80:

Aetiology of cataract in Infants in South India CauseNo of eyes% Hereditary1818 congenital Rubella syndrome2525 Embryogenesis44 Secondary66 Undetermined4747 Total BJO ; 80 :

Morphological characteristics of Nontraumatic cataract in infants MorphologyRubellaNon Rubella Total Lamellar Total03939 Nuclear25530 Post polar044 Mixed01616 Total BJO ; 80 :

Childhood cataract study Bilateral cases 70% of cases were bilateral  Mean age at 1st presentation 5.5 yrs  60% of children had a manifest squint  44% of children had nystagmus

Why do children come so late? Reasons given by parent for Delay Child unfit 3% Advised to delay 30% Father away 5% No money 24% No time 7% Unaware treatment available 15% Too young 7% Other 9%

Why do children come so late? Advise from health professional Do not require hospital visit 4% Unknown 11% Go to hospital now 46 % Delay visit for few months 27% Delay visit atleast one year 12%

Conclusion  Most of the cataracts in children are potentially preventable  Significant cataracts are due to Rubella virus  Autosomal recessive inheritance needs to be studied in detail

Recommendations  Parents and teachers to be educated  Create awareness among paramedical & medical staff involved in treating children  Develop a network between pediatrician, general ophthalmologist and paediatric ophthalmologist to achieve a good referral system

Recommendations  By proper immunisation and health education, Rubella etiology can be eradicated  Should insist that children before getting admitted to blind school have consultation with paediatric ophthalmologist  Train more paediatric ophthalmologists & to setup more paediatric ophthalmic units

Screening of children  A pediatrician or family physician should examine a new born eye  All infants by 6 months of age should be screened for ocular health by an ophthalmologist  By age 3 years all children should have their visual acuity estimated  Screening at school should become a routine procedure every year in all schools