Aravind Eye Hospital & Postgraduate Institute of Ophthalmology and Etiology of Congenital Cataract Morphology and Etiology of Congenital Cataract Dr.P.Vijayalakshmi MS.DO Chief,Paediatric Ophthalmology

Introduction Cataractogenesis

Development of the lens

 ns structures include embryonal, fetal nuclei, cortex, lens epithelium & lens capsule  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

Classification Morphological Classification   Anterior  Posterior  Central  Diffuse

  Anterior   Anterior polar cataract   Anterior pyramidal cataract   Anterior capsular cataract   Posterior   Posterior polar cataract   Posterior cortical cataract   Posterior lenticonus   Mittindorf’s dot   PHPV

 Central  Nuclear  Lamellar  Sutural  Diffuse  Blue dot cataract  Total cataract  Membranous cataract

Anterior polar cataract  Small opacity less than 3mm in size  Located at the anterior of the lens  Located at the anterior pole of the lens  90%sporadic, 10%autosomal dominant  Usually unilateral and stationary  No significant visual symptoms

Anterior pyramidal cataract  Conical opacity with apex of the cone into the anterior chamber  Conical opacity with apex of the cone projecting into the anterior chamber  Measures 2-2.5mm in diameter  Usually bilateral  Occurs sporaidically

Anterior capsular cataract  located at the centre of anterior capsule  Opacity located at the centre of anterior capsule  Can be associated with anterior segment disorder like persistant pupillary membrane  Can also be secondary to inflammation and trauma to the eye

Posterior polar cataract  Small opacity at posterior capsule  as autosomal dominant and recessive form  Inherited as autosomal dominant and recessive form  Can cause gross visual impairment  Can be associated with Mittindorf’s dot

Posterior cortical cataract  Opacity located at the posterior capsule  Can be secondary to posterior segment disorder like PHPV  Also be secondary to trauma and inflammation

Posterior lenticonus  Thinning and protrusion of center of the capsule posteriorly  Thinning and protrusion of center of the posterior capsule posteriorly  Associated with posterior lenticular opacity  Characterised by late onset

Nuclear cataract  Embryonic on fetal nuclear opacity  Congenital onset,  Congenital onset, Non- progressive  Can be unilateral or bilateral  Autosomal dominant inherritance  Associated with microphthalmos and microcornea  Common presentation of intrauterine infections like rubella virus

Lamellar cataract  Lenticular opacity between clear nucleus and cortex  Lenticular opacity sandwitched between clear nucleus and cortex  Cataract develops in layers  Associated with peripheral cortical riders  Usually bilateral with variable density  Inherited as autosomal dominant

Sutural cataract  Opacities of lens sutures  Seldom impairs vision  Inherited as X- linked trait

Blue dot cataract  Characterised by multicoloured small dot opacities  Characterised by multicoloured small dot like opacities  Inherited as autosomal dominant  Visually asymptomatic  Commonly seen in young adults and in Down’s syndrome

Total cataract  Complete opacification of the lens  Usually bilateral  Can progression of anyone above said partial cataracts  Can be progression of anyone above said partial cataracts  Autosomal dominant inheritance  Can also be the result of posterior segment diseases, inflammations and trauma

Membranous cataract  Fibrotic lens opacity where both the fuse together  Fibrotic lens opacity where both the capsules fuse together  because of the re- absorption of lens protein  May be due to long standing total cataract

Etiology  factors  Hereditary factors  Non hereditary factors

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

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

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

associated with Autosomal syndrome 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)

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

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

associated with Chromosomal anomalies 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

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

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

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

Conclusions  Still 50% of congenital cataracts are to be idiopathic  Still 50% of congenital cataracts are considered to be idiopathic  Most of the causes are potentially preventable  Location of opacity can be a clue to the time of intrauterine insult

Conclusions  To a certain extent morphology of the cataract can tell something about etiology  Autosomal recessive inheritance needs to be studied in detail