Cindy Niangsuanbawi, B. Optom

Optometry Intern, Dr. Shroff’s Charity Eye Hospital, New Delhi, India

 

A well-developed normal crystalline lens is transparent which focuses the light entering the eye onto the retina. Cataract means opacity of the transparent lens, which can cause a decrease in vision and may lead to blindness if left untreated. You might have noticed the eyes of your grandparents becoming cloudy as they become older and may complain of diminution of vision. This is due to degenerative changes of the already-formed normal lens. 

As we go through the ageing process in life, our lens also ages with time. We can say that cataract is very common in middle aged and old people. But a new-born baby child can also develop cataracts due to some disturbances in the development of the crystalline lens. When the disturbance occurs before birth, it is called congenital cataract and developmental cataract may occur from infancy to adolescence.

Listed below are a few of the aetiologies of congenital and developmental cataract.

  1. Idiopathic: Any unknown cause.
  2. Heredity: It can be inherited with or without systemic diseases. The most common with systemic diseases is Down syndrome,(1) Lowe syndrome, Norrie syndrome, Cerebrovasculo-facial syndrome, and Stickler Syndrome.(2)
  3. Maternal factors: The mother may have history of illness, infection (like rubella, toxoplasmosis etc), drugs ingestion (corticosteroids, thalidomide) and maternal exposure to radiation can also cause congenital cataract. (3)
  4. Foetal/infantile: Deficiency of oxygen owing to placental haemorrhage, birth trauma, metabolic disorders, malnutrition in early infancy, and some are associated to other ocular abnormalities such as microphthalmos, aniridia or microcornea. (4)
  5. Trauma (Birth trauma): Any history of trauma can also cause cataract in infants.

 

Table 1: Morphological classification of congenital and developmental cataract according to the effects on vision.(3-8)

Visually significant congenital cataract Visually insignificant Congenital cataract
Polar Cataract:

  • Anterior polar cataract: Due to developmental anomaly
    of anterior chamber and corneal perforation.
  • Posterior polar cataract : It may be associated with
    Persistent hyaloid artery remnants (Mittendorf dot), Posterior lenticonus and Persistent
    hyperplastic primary vitreous (PHPV)
Capsular cataract

  • Anterior (rare and does not grow)
  • Posterior ( may be associated with persistent hyaloid
    artery)
Nuclear

  • Total nuclear cataract : It involves the embryonic and
    foetal nucleus
Nuclear

  • Partial nuclear cataract :It involves the embryonic
    nucleus characterised by a small rounded powdery opacity lying exactly in the centre of the
    lens.
Cortical cataract:

  • Lamellar/Zonular cataract : It is the most common type
    of congenital cataract causing visual impairment.
Generalised cataract:

  • Coronary cataract : Clubbed shaped opacities arranged
    radially in the periphery
  • Blue dot cataract: Multiple bluish dots situated in the
    periphery.
Generalised cataract:

  • Total congenital cataract: It is due to maternal
    rubella infection in the first trimester. The lens matter may remain soft or can even liquefy
    (congenital Morgagnian cataract).
  • Congenital rubella cataract may occur alone or as part
    of the classical rubella syndrome which consists of:
  • Ocular defects
  • Ear defects(deafness )
  • Heart defects

Congenital Membranous cataract :Due to total or partial absorption of congenital cataract, only thin
membranous cataract remains.

Sutural cataract:(punctate opacities in various shapes around the y sutures)

  • Floriform cataract ( arranged like the petals of a
    flower)
  • Coralliform cataract (arranged in the form of a coral)
  • Spear-shaped cataract (Looks like scattered crystalline
    needles)
  • Anterior axial embryonic cataract (as fine dots near
    the anterior Y-suture)

Regardless of the aetiology, early diagnosis in congenital cataracts is the key to reach good visual function. Late diagnosis and treatment may lead to irreversible deprivation of vision, amblyopic eye, severe visual impairment, or blindness. Prompt treatment and management of a visually significant cataract is necessary to allow proper development of the lens.

Spreading awareness among pregnant women in the community, prenatal imaging diagnosis by ultrasound and regular eye screening in children is needed for early detection. Prompt management and treatment can have a tremendous impact on the life of a child with cataract and their families.

 

References:

  1. Roizen, N. J., Mets, M. B., & Blondis, T. A. (1994). Ophthalmic disorders in children with Down syndrome. Developmental Medicine & Child Neurology, 36(7), 594-600.
  2. Santana, A., & Waiswo, M. (2011). The genetic and molecular basis of congenital cataract. Arquivos brasileiros de oftalmologia, 74, 136-142.
  3. Livingston, P. M., Carson, C. A., & Taylor, H. R. (1995). The epidemiology of cataract: a review of the literature. Ophthalmic epidemiology, 2(3), 151-164.
  4. Basak, S. K. (2019). Essentials of ophthalmology. Jaypee Brothers Medical Publishers.
  5. Taylor, D. (1998). Congenital cataract: the history, the nature, and the practice. Eye, 12(1), 9-36.
  6. Heijl, A., & Leske, M. C. (2007). Cataract epidemiology. Ophthalmology, 114(1), 201.
  7. Fakhoury, O., Aziz, A., Matonti, F., Benso, C., Belahda, K., & Denis, D. (2015). Epidemiologic and etiological characteristics of congenital cataract: study of 59 cases over 10 years. Journal Français d’Ophtalmologie, 38(4), 295-300.
  8. Benso C, Belahda K, Denis D.  Fakehoury O, Aziz A, Matonti F, Epidemiologic and etiology characteristic of congenital cataract.